Tiller angle of rice （Oryza sativa L.） is an important agronomic trait that contributes to grain production, and has long attracted attentions of breeders for achieving ideal plant architecture to improve grain yiel...Tiller angle of rice （Oryza sativa L.） is an important agronomic trait that contributes to grain production, and has long attracted attentions of breeders for achieving ideal plant architecture to improve grain yield. Although enormous efforts have been made over the past decades to study mutants with extremely spreading or compact tillers, the molecular mechanism underlying the control of tiller angle of cereal crops remains unknown. Here we report the cloning of the LAZY1 （LA1） gene that regulates shoot gravitropism by which the rice tiller angle is controlled. We show that LA1, a novel grass-specific gene, is temporally and spatially expressed, and plays a negative role in polar auxin transport （PAT）. Loss-of-function of LA1 enhances PAT greatly and thus alters the endogenous IAA distribution in shoots, leading to the reduced gravitropism, and therefore the tiller-spreading phenotype of rice plants.展开更多
Polyamines are implicated in regulating various developmental processes in plants, but their exact roles and how they govern these processes still remain elusive. We report here an Arabidopsis bushy and dwarf mutant, ...Polyamines are implicated in regulating various developmental processes in plants, but their exact roles and how they govern these processes still remain elusive. We report here an Arabidopsis bushy and dwarf mutant, bud2, which results from the complete deletion of one member of the small gene family that encodes S-adenosylmethionine decarboxylases （SAMDCs） necessary for the formation of the indispensable intermediate in the polyamine biosynthetic pathway. The bud2 plant has enlarged vascular systems in inflorescences, roots, and petioles, and an altered homeostasis ofpolyamines. The double mutant of bud2 and samdcl, a knockdown mutant of another SAMDC member, is embryo lethal, demonstrating that SAMDCs are essential for plant embryogenesis. Our results suggest that polyamines are required for the normal growth and development of higher plants.展开更多
The ratio of auxin and cytokinin plays a crucial role in regulating aerial architecture by promoting or repressing axillary bud outgrowth. We have previously identified an Arabidopsis mutant bud2 that displays altered...The ratio of auxin and cytokinin plays a crucial role in regulating aerial architecture by promoting or repressing axillary bud outgrowth. We have previously identified an Arabidopsis mutant bud2 that displays altered root and shoot architecture, which results from the loss-of-function of S-adenosylmethionine decarboxylase 4 （SAMDC4）. In this study, we demonstrate that BUD2 could be induced by auxin, and the induction is dependent on auxin signaling. The mutation of BUD2 results in hyposensitivity to auxin and hypersensitivity to cytokinin, which is confirmed by callus induction assays. Our study suggests that polyamines may play their roles in regulating the plant architecture through affecting the homeostasis of cytokinins and sensitivities to auxin and cytokinin.展开更多
Brassinosteroids （BRs） are a major group of plant hormones that regulate plant growth and development. BRI1, a protein localized to the plasma membrane, functions as a BR receptor and it has been proposed that its k...Brassinosteroids （BRs） are a major group of plant hormones that regulate plant growth and development. BRI1, a protein localized to the plasma membrane, functions as a BR receptor and it has been proposed that its kinase activity has an essential role in BR-regulated plant growth and development. Here we report the isolation and molecular characterization of a new allele of bril, bril-301, which shows moderate morphological phenotypes and a reduced response to BRs under normal growth conditions. Sequence analysis identified a two-base alteration from GG to AT, resulting in a conversion of 989G to 9891 in the BRI1 kinase domain. An in vitro assay of kinase activity showed that bril-301 has no detectable autophosphorylation activity or phosphorylation activity towards the BRI1 substrates TTL and BAK1. Furthermore, our results suggest that bril-301, even with extremely impaired kinase activity, still retains partial function in regulating plant growth and development, which raises the question of whether BRI1 kinase activity is essential for BR-mediated growth and development in higher plants.展开更多
In rainfed areas of northwestern China,maize production is constrained mainly by low temperature during early growth and water limitation during the entire growth period.Plastic film mulching is commonly used to incre...In rainfed areas of northwestern China,maize production is constrained mainly by low temperature during early growth and water limitation during the entire growth period.Plastic film mulching is commonly used to increase maize yield in this area,because it increases topsoil temperature and moisture content as well as water use efficiency.However,the physiological and anatomical bases of maize yield improvement with plastic film mulching are not well understood.The effects of plastic film mulching and planting density on maize yield,photosynthetic characteristics,respiration,leaf anatomy,and root growth were studied in a two-year field experiment conducted on the Loess Plateau of China in 2017 and 2018.The experiment used a split-split plot design with two mulching treatments(plastic film mulching and no mulching),two planting densities(7.5×104 and10.5×104 plants ha-1),and two maize cultivars,Zhengdan 958 and Xianyu 335.Compared with no mulching,plastic film mulching increased maize yields by 31.1%–46.4%in 2017 and3.6%–34.7%in 2018.Compared with low planting density,high planting density significantly increased and slightly reduced yields of both cultivars in the dry year 2017 and the rainy year 2018,respectively.Plastic film mulching increased photosynthesis and respiration as well as leaf stomatal density and aperture.Photosynthetic rate,dark respiration,and stomatal conductance and aperture were lower at high planting than at low planting density.Maize yield was positively correlated with photosynthesis,dark respiration,and stomatal aperture.Mulching increased root dry weight and length in the 0–20 cm soil layer and root activity at maturity.Overall,the changes in root growth and leaf anatomy resulted in increased photosynthesis and dark respiration,and the increased photosynthesis contributed to the increase in grain yield and biomass production under plastic film mulching conditions.Our results increase understanding of the physiological mechanisms by which plastic film mulching increases maize yield in water-and temperature-limited areas.展开更多
BACKGROUND： Estrogen has been clinically demonstrated to attenuate ischemic brain injury. However, the precise mechanisms remain controversial. OBJECTIVE： To investigate the effects of estradiol on angiopoietin-1 mR...BACKGROUND： Estrogen has been clinically demonstrated to attenuate ischemic brain injury. However, the precise mechanisms remain controversial. OBJECTIVE： To investigate the effects of estradiol on angiopoietin-1 mRNA and Bcl-2 expression, as well as apoptosis and cerebral blood flow, in ovadectomized rats with focal cerebral ischemia following reperfusion. DESIGN, TIME AND SETTING： Randomized, controlled, animal experiment. The study was performed at the Central Laboratory, Chongqing Medical University from September to December 2005. MATERIALS： Estradiol benzoate was purchased from Shanghai Ninth Pharmaceutical Factory; corn oil was purchased from Walmart Supercenter; TUNEL kit, rabbit anti-rat Bcl-2 polyclonal antibody, and biotin-labeled goat anti-rabbit antibody were purchased from Wuhan Boster, China. METHODS： Healthy, female, 6-month-old Wistar rats-wild-type and estrogen alpha receptor gene knockout （ERKO）-were randomly divided into estradiol and control groups with 25 animals in each group. The rats were intramuscularly injected with estradiol benzoate （100 μg/kg per day） at 30 days following bilateral ovariectomy or corn oil （1 mL/kg per day） for seven consecutive days. Following administration, cerebral ischemia/reperfusion models were established using the right middle cerebral artery occlusion （MCAO） method. After 30 minutes of MCAO, estradiol and control groups were separately injected with estradiol benzoate and corn oil with the above-mentioned doses. MAIN OUTCOME MEASURES： Cell apoptosis was determined by TUNEL; angiopoietin-1 mRNA and Bcl-2 gene expression was determined, respectively, by immunohistochemical staining and RT-PCR. In addition, changes in cerebral blood flow were measured by laser Doppler flowmetry. RESULTS： Changes in angiopoietin-1 mRNA and cerebral blood flow in estradiol-treated, wild-type, MCAO rats following ischemia/reperfusion were greater than in control rats （P 〈 0.01 or 0.05）. However, no significant difference was observed between estradiol-treated ERKO MCAO rats and control rats. In addition, estradiol-treated wild-type and ERKO MCAO rats exhibited significantly increased Bcl-2 expression （P 〈 0.05） and decreased number of apoptotic cells in brain tissues compared with control groups （P 〈 0.05）. CONCLUSION： Estradiol upregulated angiopoietin-1 mRNA and Bcl-2 expression, suggesting that estradiol might be involved in protective mechanisms of cerebral ischemia/reperfusion injury.展开更多
BACKGROUND： Epidemiologic studies have indicated that the incidence of stroke in premenopausal females is lower than in males at the same age, but it significantly rises in postmenopansal females. Estrogen is used cl...BACKGROUND： Epidemiologic studies have indicated that the incidence of stroke in premenopausal females is lower than in males at the same age, but it significantly rises in postmenopansal females. Estrogen is used clinically to alleviate injury caused by cerebral ischemia, it has been hypothesized that the neuroprotective role of estrogen relates to angiopoietin （Angpt）, which plays an important role in vascularization, vascular remodeling and maturation. OBJECTIVE： To observe and validate the effect of estradiol on angiopoietin-1 （Angptl） mRNA expression in ovariectomized rats with focal cerebral ischemia after reperfusion, so as to explore the molecular mechanisms of estradiol-mediated protection from cerebral ischemic damage. DESIGN, TIME AND SETTING： Randomized, controlled, molecular biology, prospective animal study. The experiment was performed at the Central Laboratory of Chongqing Medical University from September to December 2005. MATERIALS： Fifty healthy female wild type （WT） rats aged 6 months and fifty female rats aged 6 months with knockout of the estrogen-alpha receptor gene （ERKO）. METHODS： WT rats and ERKO rats were divided into estradiol and control groups （n = 25）, and injected intramuscularly with estradiol benzoate （100μg/kg per day） or corn oil （l mL/kg per day） for 7 days, 30 days after bilateral ovariectomy. Rat models of cerebral ischemia/reperfusion were established with the middle cerebral artery occlusion method. After 30 minutes of middle cerebral artery occlusion, rats from the estradiol and control groups were injected intramuscularly with estradiol benzoate or corn oil at the above dose. MAIN OUTCOME MEASURES： We used radio-immunity analysis and laser-Doppler flowmetry to measure plasma estradiol levels and changes in cerebral blood flow. We used immunohistochemical staining of CD34 epitopes to measure changes in the capillary density in brain following cerebral iscbemia/reperfusion, and quantitative RT-PCR analysis to assess mRNA expression levels of Angptl, Angpt2, Tie2, vascular endothelial growth factor （Vegf）, VegfR1, and Veg, fR2. RESULTS： In WT ovariectomized rats treated with estradiol, the change in cerebral blood flow following cerebral ischemia/reperfusion, capillary density in the basal nuclei and parietal lobe cortex and Angptl mRNA level were significantly higher than in the control group （P 〈 0.01 ）. We did not identify any such changes in ERKO rats treated with estradiol. In addition, the plasma estradiol levels in WT and ERKO ovariectomized rats treated with estradiol were remarkably higher than in their corresponding control groups （P 〈 0.01）. CONCLUSION： Angptl is a critical factor in many processes during the repair of cerebral ischemia/reperfusion injury. For example, it confers estrogen-mediated protection, restoration of cerebral blood flow and increases in brain capillary density. It is emerging as an important molecule for estradiol-mediated neuroprotection.展开更多
BACKGROUND： Previous research has proved that nerve growth factor （NGF） participates in the onset of asthma by the induction of neurogenic inflammation. OBJECTIVE： To investigate the effect of interleukin-13 （IL...BACKGROUND： Previous research has proved that nerve growth factor （NGF） participates in the onset of asthma by the induction of neurogenic inflammation. OBJECTIVE： To investigate the effect of interleukin-13 （IL-13） and interferon- γ; （IFN- γ ） on the expression of NGF mRNA in the splenic lymphocytes of bronchial asthma rats. DESIGN, TIME AND SETTING： The experiment, a completely randomized study based on cellular immunology, was performed in the Laboratory of Neurology in Chongqing Medical University and the Department of Clinical Pharmacy in College of Clinical Medicine, Chongqing Medical University （Chongqing, China） from January 2006 to April 2007. MATERIALS： Four adult male Wistar rats were used in this study. Rat IL-13, IFN- γ probe and the total RNA extraction kit were produced by Shanghai Sangon Biological Technology ＆ Services Co., Ltd （China）. The NGF ELISA kit was a product of Wuhan Boster Bioengineering Co., Ltd （China）. A Du-70 automatic UV spectrophotometer was produced by Beckman Company （USA）. METHODS： Rats were subjected to 1-mL intraperitoneal injections each containing 100 mg of ovalbumin, and were sensitized by using antigen solution, which was sensitized with 5×10^9 Bacillus pertussis and 100 mg aluminum hydroxide powder. Four rats were challenged with 1% ovalbumin using an ultrasonic nebulizer for 60 minutes to establish an asthmatic model. After rats were anesthetized, splenic lymphocytes were isolated and cultured in medium, which was supplemented with IL-13 or IFN- γ, for 0, 12, 24 or 48 hours. A parallel study was conducted with cultured splenic lymphocytes, which were divided into a control group, an IL-13 group and an IFN- γ group. Culture medium was added with different concentrations of IL-13 （10, 50, 100 U g/L） and IFN- γ; （1, 10, 50 u g/L）; 24 hours later, all samples were harvested. MAIN OUTCOME MEASURES： The expression levels of NGF mRNA were detected by reverse transcription-polymerase chain reaction. RESULTS： In the control group, the lymphocytes of the asthmatic model expressed NGF mRNA in a time-dependent manner. Alter lymphocytes were cultured with IL-13 at a final concentration of 50 u g/L for 12, 24 or 48 hours, expression of NGF mRNA was upregulated in a time-dependent manner to higher levels than the basal values at the same time points （P 〈 0.01 ）. IL- 13 upregulated the expression of NGF mRNA in a dose-dependent manner, and the NGF mRNA expression levels at middle and high concentrations of IL-3 were significanlly higher than the values at a low concentration of IL-13 （P 〈 0.05）. With increasing IFN- γ concentration, the expression of NGF mRNA was gradually downregulated. The low concentration group showed lower levels of NGF mRNA than the blank control group, while the middle and high concentration IFN- γ, groups showed lower levels than the low concentration group （P 〈 0.05）. CONCLUSION： In asthmatic rats, IL-13, a Th2 cytokine, upregulates the expression ofNGF mRNA, while IFN- γ, a Thl cytokine, downregulates NGF mRNA expression. The effects of both cytokines were time and dose dependent. Th 1/Th2 cytokine immune imbalance may indirectly induce airway neurogenic inflammation by regulating NGF mRNA expression.展开更多
We propose a novel system for synchronous measurement of out-of-plane deformation and two orthogonal slopes using a single camera. The linearly polarized reference beam introduced by an optical fiber interferes with t...We propose a novel system for synchronous measurement of out-of-plane deformation and two orthogonal slopes using a single camera. The linearly polarized reference beam introduced by an optical fiber interferes with the unpolarized object beam to measure the out-of-plane deformation. A modified Mach–Zehnder interferometer is used to measure the two orthogonal slopes of the out-of-plane deformation. One of the object beams of the Mach–Zehnder interferometer is an unpolarized beam, and the other object beam is split into two orthogonal linearly polarized object beams by a polarizing prism. The two beams are orthogonally polarized. Hence, they will not interfere with each other. The two polarized beams respectively interfere with the unpolarized beam to simultaneously measure the two orthogonal slopes of the out-of-plane deformation. In addition, the imaging lens and apertures are respectively placed in three optical paths to independently control the carrier frequencies and shearing amounts. The effectiveness of this method can be proved by measuring two pressure-loaded circular plates.展开更多
Rice tiller angle is a key agronomic trait that has significant effects on the establishment of a high-yield rice population.However,the molecular mechanism underlying the control of rice tiller angle remains to be cl...Rice tiller angle is a key agronomic trait that has significant effects on the establishment of a high-yield rice population.However,the molecular mechanism underlying the control of rice tiller angle remains to be clarified.Here,we characterized the novel tiller-angle gene LAZY4(LA4)in rice through map-based cloning.LA4 encodes a C3H2C3-type RING zinc-finger E3 ligase localized in the nucleus,and an in vitro ubiquitination assay revealed that the conserved RING finger domain is essential for its E3 ligase activity.We found that expression of LA4 can be induced by gravistimulation and that loss of LA4 function leads to defective shoot gravitropism caused by impaired asymmetric auxin redistribution upon gravistimulation.Genetic analysis demonstrated that LA4 acts in a distinct pathway from the starch biosynthesis regulators LA2 and LA3,which function in the starch-statolith-dependent pathway.Further genetic analysis showed that LA4 regulates shoot gravitropism and tiller angle by acting upstream of LA1 to mediate lateral auxin transport upon gravistimulation.Our studies reveal that LA4 regulates shoot gravitropism and tiller angle upstream of LA1 through a novel pathway independent of the LA2-LA3-mediated gravity-sensing mechanism,providing new insights into the rice tiller-angle regulatory network.展开更多
Hadal trenches are characterized by enhanced and infrequent high-rate episodic sedimentation events that likely introduce not only labile organic carbon and key nutrients but also new microbes that significantly alter...Hadal trenches are characterized by enhanced and infrequent high-rate episodic sedimentation events that likely introduce not only labile organic carbon and key nutrients but also new microbes that significantly alter the subseafloor microbiosphere.Currently,the role of high-rate episodic sedimentation in controlling the composition of the hadal subseafloor microbiosphere is unknown.Here,analyses of carbon isotope composition in a~750 cm long sediment core from the Challenger Deep revealed noncontinuous deposition,with anomalous ^(14)C ages likely caused by seismically driven mass transport and the funneling effect of trench geomorphology.Microbial community composition and diverse enzyme activities in the upper~27 cm differed from those at lower depths,probably due to sudden sediment deposition and differences in redox condition and organic matter availability.At lower depths,microbial population numbers,and composition remained relatively constant,except at some discrete depths with altered enzyme activity and microbial phyla abundance,possibly due to additional sudden sedimentation events of different magnitude.Evidence is provided of a unique role for high-rate episodic sedimentation events in controlling the subsurface microbiosphere in Earth’s deepest ocean floor and highlight the need to perform thorough analysis over a large depth range to characterize hadal benthic populations.Such depositional processes are likely crucial in shaping deep-water geochemical environments and thereby the deep subseafloor biosphere.展开更多
In this study,an innovative technique is introduced to significantly enhance the sensitivity of electronic speckle pattern interferometry(ESPI)for the dynamic assessment of specular(mirrorlike)object deformations.By u...In this study,an innovative technique is introduced to significantly enhance the sensitivity of electronic speckle pattern interferometry(ESPI)for the dynamic assessment of specular(mirrorlike)object deformations.By utilizing a common-path illumination strategy,wherein illumination and observation beams are precisely aligned,this method effectively doubles the optical path difference,leading to a twofold increase in measurement sensitivity.In addition,this method mitigates the effects of speckle noise on the measurement of minor deformations,expanding the applications of ESPI.Theoretical and experimental evaluations corroborate the efficacy of this approach.展开更多
Background and Aims:Acute liver failure(ALF)is a life-threatening clinical problem with limited treatment options.Administration of human umbilical cord mesenchymal stem cells(hUC-MSCs)may be a promising approach for ...Background and Aims:Acute liver failure(ALF)is a life-threatening clinical problem with limited treatment options.Administration of human umbilical cord mesenchymal stem cells(hUC-MSCs)may be a promising approach for ALF.This study aimed to explore the role of hUC-MSCs in the treat-ment of ALF and the underlying mechanisms.Methods:A mouse model of ALF was induced by lipopolysaccharide and d-galactosamine administration.The therapeutic effects of hUC-MSCs were evaluated by assessing serum enzyme activity,histological appearance,and cell apoptosis in liver tissues.The apoptosis rate was analyzed in AML12 cells.The levels of inflammatory cytokines and the phenotype of RAW264.7 cells co-cultured with hUC-MSCs were detected.The C-Jun N-terminal kinase/nuclear factor-kappa B signal-ing pathway was studied.Results:The hUC-MSCstreatment decreased the levels of serum alanine aminotransferase and aspartate aminotransferase,reduced pathological damage,alleviated hepatocyte apoptosis,and reduced mortality in vivo.The hUC-MSCs co-culture reduced the apoptosis rate of AML12 cells in vitro.Moreover,lipopolysaccharide-stimulated RAW264.7 cells had higher levels of tumor necrosis factor-α,interleukin-6,and interleukin-1β and showed more CD86-positive cells,whereas the hUC-MSCs co-culture reduced the levels of the three inflammatory cytokines and increased the ratio of CD206-positive cells.The hUC-MSCs treatment inhibited the activation of phosphorylated(p)-C-Jun N-terminal kinase and p-nuclear factor-kappa B not only in liver tissues but also in AML12and RAW264.7 cells co-cultured with hUC-MSCs.Conclusions:hUC-MSCs could alleviate ALF by regulating hepatocyte apoptosis and macrophage polarization,thus hUC-MSC-based cell therapy may be an alternative option for patients with ALF.展开更多
Background:An economical and integrated high-throughput primary screening strategy was developed for high-aerobic microbe Monascus purpureus cultivation.A novel and effective mixture culture method was proposed and us...Background:An economical and integrated high-throughput primary screening strategy was developed for high-aerobic microbe Monascus purpureus cultivation.A novel and effective mixture culture method was proposed and used to realize the whole mutant library being high-throughput screened after mutagenesis.Results:The good correlation of fermentation results between differing-scale cultivations confirmed the feasibility of utilizing the 48-deep microtiter plates(MTPs)as a scale-down tool for culturing high-aerobic microbes.In addition,the fluid dynamics of 24-,48-,and 96-deep MTPs and 500-mL shake flask were studied respectively using the computational fluid dynamic(CFD)tool ANSYS CFX 11.0 to get better understanding of their turbulent regimes.Conclusions:The by-product citrinin production had no significant change while the pigment production had improved.As a result,the high-yield strain T33-6 was successfully screened out and the pigment was more than 50%higher than that of the parental strain in the shake flask.展开更多
Tillering in rice is one of the most important agronomic traits.Rice tiller development can be divided into two main processes: the formation of the axillary bud and its subsequent outgrowth.Several genes critical for...Tillering in rice is one of the most important agronomic traits.Rice tiller development can be divided into two main processes: the formation of the axillary bud and its subsequent outgrowth.Several genes critical for bud formation in rice have been identified by genetic studies;however,their molecular functions and relationships are still largely unknown.Here,we report that MONOCULM 1 (MOC1) and MONOCULM 3/ TILLERS ABSENT 1/STERILE AND REDUCED TILLERING 1 (MOC3/TAB1/SRT1),two vital regulators for tiller formation in rice,physically interact to regulate tiller bud outgrowth through upregulating the expression of FLORAL ORGAN NUMBER 1 (FON1),the homolog of CLAVATA1 in rice.We found that M0C3 is able to directly bind the promoter ofFONI and subsequently activate FON1 expression.MOC1 functions as a coactivator of MOC3,whereas it could not directly bind the FON1 promoter,and further activated FON1 expression in the presence of MOC3.Accordingly,FON1 is highly expressed at axillary meristems and shows remarkably decreased expression levels in mod and moc3 mutants.Loss-of-function mutants of FON1 exhibit normal bud formation but defective bud outgrowth and reduced tiller number.Collectively,these results shed light on a joint transcriptional regulatory mechanim by MOC1 and MOC3,and establish a new framework for the control of tiller bud formation and outgrowth.展开更多
Rice tiller angle is a key agronomic trait that contributes to ideal plant architecture and grain production.LAZY1 (LA1) was previously shown to control tiller angle via affecting shoot gravitropism,but the underlying...Rice tiller angle is a key agronomic trait that contributes to ideal plant architecture and grain production.LAZY1 (LA1) was previously shown to control tiller angle via affecting shoot gravitropism,but the underlying molecular mechanism remains largely unknown.In this study,we identified an LA1-interacting protein named Brevis Radix Like 4 (OsBRXL4).We showed that the interaction between OsBRXL4 and LA1 occurs at the plasma membrane and that their interaction determines nuclear localization of LA1.We found that nuclear localization of LA1 is essential for its function,which is different from AtLA1,its Arabidopsis ortho.log.Overexpression of OsBRXL4 leads to a prostrate growth phenotype,whereas OsBRXLs RNAi plants,in which the expression levels of OsBRXLI,OsBRXL4,and OsBRXL5 were decreased,display a compact phenotype.Further genetic analysis also supported that OsBRXL4 controls rice tiller angle by affecting nuclear localization of LA1.Consistently,we demonstrated that OsBRXL4 regulates the shoot gravitropism through affecting polar auxin transport as did LA1.Taken together,our study not only identifies OsBRXL4 as a regulatory component of rice tiller angle but also provides new insights into genetic regulation of rice plant architecture.展开更多
WUSCHEL （WUS） plays an essential role for the maintenance of meristem activity in dicots, but its function is still elusive in monocots. We isolated a new monoculm mutant, monoculm 3 （moc3）, in which a point mutat...WUSCHEL （WUS） plays an essential role for the maintenance of meristem activity in dicots, but its function is still elusive in monocots. We isolated a new monoculm mutant, monoculm 3 （moc3）, in which a point mutation causes the premature termination of rice O. sativa WUS （OsWUS）. Morphological observation revealed that the formation of tiller buds was disrupted in moc3. MOC3 was localized in the nuclear and could interact with TOPLESS-RELATED PROTEINS （TPRs）. The expression of MOC3 was induced by cytokinins and defection of MOC3 affected the expression of several two-component cytokinin response regulators, OsRRs and ORRs. Our results suggest that MOC3 is required for the formation of axillary buds and has a complex relationship with cytokinins.展开更多
Rice tillering is an important agronomic trait affecting grain yield.Here,we identified a high-tillering mutant tillering20(t20),which could be restored to the wild type by treatment with the strigolactone(SL)analog r...Rice tillering is an important agronomic trait affecting grain yield.Here,we identified a high-tillering mutant tillering20(t20),which could be restored to the wild type by treatment with the strigolactone(SL)analog rac-GR24.T20 encodes a chloroplast ζ-carotene isomerase(Z-ISO),which is involved in the biosynthesis of ca-rotenoids and their metabolites,SL and abscisic acid(ABA).The t20 mutant has reduced SL and ABA,raising the question of how SL and ABA biosynthesis is coordinated,and whether they have overlapping functions in tillering.We discovered that rac-GR24 stimulated T20 expression and enhanced all-trans-p-carotene biosynthesis.Importantly,rac-GR24 also stimulated expression of Oryza sativa 9-CIS-EPOXY-CAROTENOID DIOXYGENASE 1(OsNCED1)through induction of Oryza sativa HOMEOBOX12(0sHOX12),promoting ABA biosynthesis in shoot base.On the other hand,ABA treatment significantly repressed SL biosynthesis and the ABA biosynthetic mutants displayed elevated SL biosynthesis.ABA treatment reduced the number of basal tillers in both t20 and wild-type plants.Furthermore,while ABA-deficient mu-tants aba1 and aba2 had the same number of basal tillers as wild type,they had more unproductive upper tillers at maturity.This work demonstrates complex interactions in the biosynthesis of carotenoid,SLs and ABA,and reveals a role for ABA in the regulation of rice tillering.展开更多
基金grants from the Ministry of Science and Technology of China(2005CB 1208)the National Natural Science Foundation of China(30330040 and 30570161).
文摘Tiller angle of rice （Oryza sativa L.） is an important agronomic trait that contributes to grain production, and has long attracted attentions of breeders for achieving ideal plant architecture to improve grain yield. Although enormous efforts have been made over the past decades to study mutants with extremely spreading or compact tillers, the molecular mechanism underlying the control of tiller angle of cereal crops remains unknown. Here we report the cloning of the LAZY1 （LA1） gene that regulates shoot gravitropism by which the rice tiller angle is controlled. We show that LA1, a novel grass-specific gene, is temporally and spatially expressed, and plays a negative role in polar auxin transport （PAT）. Loss-of-function of LA1 enhances PAT greatly and thus alters the endogenous IAA distribution in shoots, leading to the reduced gravitropism, and therefore the tiller-spreading phenotype of rice plants.
基金We thank Dr Senya Matsufuji(Jikei University,Japan)for providing the yeast spe2 strain,Dr Guixian Xia(Institute of Microbiology,Chinese Academy of Sciences,China)for yeast expression vector pREP5N and ABRC stock center for BAC clones(F17K4 and T16G12)and T-DNA insertion lines(Salk_007279 and Salk_020185).This work was supported by grants from National Natural Science Foundation of China(30330040)the Ministry of Sciences and Technology of China(J02-A-001).
文摘Polyamines are implicated in regulating various developmental processes in plants, but their exact roles and how they govern these processes still remain elusive. We report here an Arabidopsis bushy and dwarf mutant, bud2, which results from the complete deletion of one member of the small gene family that encodes S-adenosylmethionine decarboxylases （SAMDCs） necessary for the formation of the indispensable intermediate in the polyamine biosynthetic pathway. The bud2 plant has enlarged vascular systems in inflorescences, roots, and petioles, and an altered homeostasis ofpolyamines. The double mutant of bud2 and samdcl, a knockdown mutant of another SAMDC member, is embryo lethal, demonstrating that SAMDCs are essential for plant embryogenesis. Our results suggest that polyamines are required for the normal growth and development of higher plants.
基金We thank Dr Ottoline Leyser （University of York, UK） for providing axrl-3 and Dr Mark Estelle （UC, San Diego, USA） for providing tirlafb2afb3 triple mutant seeds. This work was supported by a grant from the National Natural Science Foundation of China （30830009）.
文摘The ratio of auxin and cytokinin plays a crucial role in regulating aerial architecture by promoting or repressing axillary bud outgrowth. We have previously identified an Arabidopsis mutant bud2 that displays altered root and shoot architecture, which results from the loss-of-function of S-adenosylmethionine decarboxylase 4 （SAMDC4）. In this study, we demonstrate that BUD2 could be induced by auxin, and the induction is dependent on auxin signaling. The mutation of BUD2 results in hyposensitivity to auxin and hypersensitivity to cytokinin, which is confirmed by callus induction assays. Our study suggests that polyamines may play their roles in regulating the plant architecture through affecting the homeostasis of cytokinins and sensitivities to auxin and cytokinin.
基金We thank Prof Joanne Chory （The Salk Institute for Biological Studies, USA） for providing the Arabidopsis bril-101 mutant seeds. This work was supported by grants from the National Natural Science Foundation of China （grant numbers： 30070074, 30330040 and 30570161）.
文摘Brassinosteroids （BRs） are a major group of plant hormones that regulate plant growth and development. BRI1, a protein localized to the plasma membrane, functions as a BR receptor and it has been proposed that its kinase activity has an essential role in BR-regulated plant growth and development. Here we report the isolation and molecular characterization of a new allele of bril, bril-301, which shows moderate morphological phenotypes and a reduced response to BRs under normal growth conditions. Sequence analysis identified a two-base alteration from GG to AT, resulting in a conversion of 989G to 9891 in the BRI1 kinase domain. An in vitro assay of kinase activity showed that bril-301 has no detectable autophosphorylation activity or phosphorylation activity towards the BRI1 substrates TTL and BAK1. Furthermore, our results suggest that bril-301, even with extremely impaired kinase activity, still retains partial function in regulating plant growth and development, which raises the question of whether BRI1 kinase activity is essential for BR-mediated growth and development in higher plants.
基金supported by the National Key Research and Development Program of China(2016YFD0300102)supported by the Innovation Program of the Chinese Academy of Agricultural Sciences and the Elite Youth Program of the Chinese Academy of Agricultural Sciences。
文摘In rainfed areas of northwestern China,maize production is constrained mainly by low temperature during early growth and water limitation during the entire growth period.Plastic film mulching is commonly used to increase maize yield in this area,because it increases topsoil temperature and moisture content as well as water use efficiency.However,the physiological and anatomical bases of maize yield improvement with plastic film mulching are not well understood.The effects of plastic film mulching and planting density on maize yield,photosynthetic characteristics,respiration,leaf anatomy,and root growth were studied in a two-year field experiment conducted on the Loess Plateau of China in 2017 and 2018.The experiment used a split-split plot design with two mulching treatments(plastic film mulching and no mulching),two planting densities(7.5×104 and10.5×104 plants ha-1),and two maize cultivars,Zhengdan 958 and Xianyu 335.Compared with no mulching,plastic film mulching increased maize yields by 31.1%–46.4%in 2017 and3.6%–34.7%in 2018.Compared with low planting density,high planting density significantly increased and slightly reduced yields of both cultivars in the dry year 2017 and the rainy year 2018,respectively.Plastic film mulching increased photosynthesis and respiration as well as leaf stomatal density and aperture.Photosynthetic rate,dark respiration,and stomatal conductance and aperture were lower at high planting than at low planting density.Maize yield was positively correlated with photosynthesis,dark respiration,and stomatal aperture.Mulching increased root dry weight and length in the 0–20 cm soil layer and root activity at maturity.Overall,the changes in root growth and leaf anatomy resulted in increased photosynthesis and dark respiration,and the increased photosynthesis contributed to the increase in grain yield and biomass production under plastic film mulching conditions.Our results increase understanding of the physiological mechanisms by which plastic film mulching increases maize yield in water-and temperature-limited areas.
基金Supported by:the Natural Science Foundation of Chongqing,No. CSTC2006EB5030
文摘BACKGROUND： Estrogen has been clinically demonstrated to attenuate ischemic brain injury. However, the precise mechanisms remain controversial. OBJECTIVE： To investigate the effects of estradiol on angiopoietin-1 mRNA and Bcl-2 expression, as well as apoptosis and cerebral blood flow, in ovadectomized rats with focal cerebral ischemia following reperfusion. DESIGN, TIME AND SETTING： Randomized, controlled, animal experiment. The study was performed at the Central Laboratory, Chongqing Medical University from September to December 2005. MATERIALS： Estradiol benzoate was purchased from Shanghai Ninth Pharmaceutical Factory; corn oil was purchased from Walmart Supercenter; TUNEL kit, rabbit anti-rat Bcl-2 polyclonal antibody, and biotin-labeled goat anti-rabbit antibody were purchased from Wuhan Boster, China. METHODS： Healthy, female, 6-month-old Wistar rats-wild-type and estrogen alpha receptor gene knockout （ERKO）-were randomly divided into estradiol and control groups with 25 animals in each group. The rats were intramuscularly injected with estradiol benzoate （100 μg/kg per day） at 30 days following bilateral ovariectomy or corn oil （1 mL/kg per day） for seven consecutive days. Following administration, cerebral ischemia/reperfusion models were established using the right middle cerebral artery occlusion （MCAO） method. After 30 minutes of MCAO, estradiol and control groups were separately injected with estradiol benzoate and corn oil with the above-mentioned doses. MAIN OUTCOME MEASURES： Cell apoptosis was determined by TUNEL; angiopoietin-1 mRNA and Bcl-2 gene expression was determined, respectively, by immunohistochemical staining and RT-PCR. In addition, changes in cerebral blood flow were measured by laser Doppler flowmetry. RESULTS： Changes in angiopoietin-1 mRNA and cerebral blood flow in estradiol-treated, wild-type, MCAO rats following ischemia/reperfusion were greater than in control rats （P 〈 0.01 or 0.05）. However, no significant difference was observed between estradiol-treated ERKO MCAO rats and control rats. In addition, estradiol-treated wild-type and ERKO MCAO rats exhibited significantly increased Bcl-2 expression （P 〈 0.05） and decreased number of apoptotic cells in brain tissues compared with control groups （P 〈 0.05）. CONCLUSION： Estradiol upregulated angiopoietin-1 mRNA and Bcl-2 expression, suggesting that estradiol might be involved in protective mechanisms of cerebral ischemia/reperfusion injury.
基金Supported by: the Natural Science Foundation of Chongqing, No. CSTC2006EB5030
文摘BACKGROUND： Epidemiologic studies have indicated that the incidence of stroke in premenopausal females is lower than in males at the same age, but it significantly rises in postmenopansal females. Estrogen is used clinically to alleviate injury caused by cerebral ischemia, it has been hypothesized that the neuroprotective role of estrogen relates to angiopoietin （Angpt）, which plays an important role in vascularization, vascular remodeling and maturation. OBJECTIVE： To observe and validate the effect of estradiol on angiopoietin-1 （Angptl） mRNA expression in ovariectomized rats with focal cerebral ischemia after reperfusion, so as to explore the molecular mechanisms of estradiol-mediated protection from cerebral ischemic damage. DESIGN, TIME AND SETTING： Randomized, controlled, molecular biology, prospective animal study. The experiment was performed at the Central Laboratory of Chongqing Medical University from September to December 2005. MATERIALS： Fifty healthy female wild type （WT） rats aged 6 months and fifty female rats aged 6 months with knockout of the estrogen-alpha receptor gene （ERKO）. METHODS： WT rats and ERKO rats were divided into estradiol and control groups （n = 25）, and injected intramuscularly with estradiol benzoate （100μg/kg per day） or corn oil （l mL/kg per day） for 7 days, 30 days after bilateral ovariectomy. Rat models of cerebral ischemia/reperfusion were established with the middle cerebral artery occlusion method. After 30 minutes of middle cerebral artery occlusion, rats from the estradiol and control groups were injected intramuscularly with estradiol benzoate or corn oil at the above dose. MAIN OUTCOME MEASURES： We used radio-immunity analysis and laser-Doppler flowmetry to measure plasma estradiol levels and changes in cerebral blood flow. We used immunohistochemical staining of CD34 epitopes to measure changes in the capillary density in brain following cerebral iscbemia/reperfusion, and quantitative RT-PCR analysis to assess mRNA expression levels of Angptl, Angpt2, Tie2, vascular endothelial growth factor （Vegf）, VegfR1, and Veg, fR2. RESULTS： In WT ovariectomized rats treated with estradiol, the change in cerebral blood flow following cerebral ischemia/reperfusion, capillary density in the basal nuclei and parietal lobe cortex and Angptl mRNA level were significantly higher than in the control group （P 〈 0.01 ）. We did not identify any such changes in ERKO rats treated with estradiol. In addition, the plasma estradiol levels in WT and ERKO ovariectomized rats treated with estradiol were remarkably higher than in their corresponding control groups （P 〈 0.01）. CONCLUSION： Angptl is a critical factor in many processes during the repair of cerebral ischemia/reperfusion injury. For example, it confers estrogen-mediated protection, restoration of cerebral blood flow and increases in brain capillary density. It is emerging as an important molecule for estradiol-mediated neuroprotection.
基金Natural Science Foundation of Chongqing, No. [2006]24-CSTC2006EB 5030
文摘BACKGROUND： Previous research has proved that nerve growth factor （NGF） participates in the onset of asthma by the induction of neurogenic inflammation. OBJECTIVE： To investigate the effect of interleukin-13 （IL-13） and interferon- γ; （IFN- γ ） on the expression of NGF mRNA in the splenic lymphocytes of bronchial asthma rats. DESIGN, TIME AND SETTING： The experiment, a completely randomized study based on cellular immunology, was performed in the Laboratory of Neurology in Chongqing Medical University and the Department of Clinical Pharmacy in College of Clinical Medicine, Chongqing Medical University （Chongqing, China） from January 2006 to April 2007. MATERIALS： Four adult male Wistar rats were used in this study. Rat IL-13, IFN- γ probe and the total RNA extraction kit were produced by Shanghai Sangon Biological Technology ＆ Services Co., Ltd （China）. The NGF ELISA kit was a product of Wuhan Boster Bioengineering Co., Ltd （China）. A Du-70 automatic UV spectrophotometer was produced by Beckman Company （USA）. METHODS： Rats were subjected to 1-mL intraperitoneal injections each containing 100 mg of ovalbumin, and were sensitized by using antigen solution, which was sensitized with 5×10^9 Bacillus pertussis and 100 mg aluminum hydroxide powder. Four rats were challenged with 1% ovalbumin using an ultrasonic nebulizer for 60 minutes to establish an asthmatic model. After rats were anesthetized, splenic lymphocytes were isolated and cultured in medium, which was supplemented with IL-13 or IFN- γ, for 0, 12, 24 or 48 hours. A parallel study was conducted with cultured splenic lymphocytes, which were divided into a control group, an IL-13 group and an IFN- γ group. Culture medium was added with different concentrations of IL-13 （10, 50, 100 U g/L） and IFN- γ; （1, 10, 50 u g/L）; 24 hours later, all samples were harvested. MAIN OUTCOME MEASURES： The expression levels of NGF mRNA were detected by reverse transcription-polymerase chain reaction. RESULTS： In the control group, the lymphocytes of the asthmatic model expressed NGF mRNA in a time-dependent manner. Alter lymphocytes were cultured with IL-13 at a final concentration of 50 u g/L for 12, 24 or 48 hours, expression of NGF mRNA was upregulated in a time-dependent manner to higher levels than the basal values at the same time points （P 〈 0.01 ）. IL- 13 upregulated the expression of NGF mRNA in a dose-dependent manner, and the NGF mRNA expression levels at middle and high concentrations of IL-3 were significanlly higher than the values at a low concentration of IL-13 （P 〈 0.05）. With increasing IFN- γ concentration, the expression of NGF mRNA was gradually downregulated. The low concentration group showed lower levels of NGF mRNA than the blank control group, while the middle and high concentration IFN- γ, groups showed lower levels than the low concentration group （P 〈 0.05）. CONCLUSION： In asthmatic rats, IL-13, a Th2 cytokine, upregulates the expression ofNGF mRNA, while IFN- γ, a Thl cytokine, downregulates NGF mRNA expression. The effects of both cytokines were time and dose dependent. Th 1/Th2 cytokine immune imbalance may indirectly induce airway neurogenic inflammation by regulating NGF mRNA expression.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2016YFF0101803)the Hefei Municipal Natural Science Foundation (Grant No. 2021017)the Fundamental Research Funds for the Central Universities of China (Grant No. JZ2019HGTB0076)。
文摘We propose a novel system for synchronous measurement of out-of-plane deformation and two orthogonal slopes using a single camera. The linearly polarized reference beam introduced by an optical fiber interferes with the unpolarized object beam to measure the out-of-plane deformation. A modified Mach–Zehnder interferometer is used to measure the two orthogonal slopes of the out-of-plane deformation. One of the object beams of the Mach–Zehnder interferometer is an unpolarized beam, and the other object beam is split into two orthogonal linearly polarized object beams by a polarizing prism. The two beams are orthogonally polarized. Hence, they will not interfere with each other. The two polarized beams respectively interfere with the unpolarized beam to simultaneously measure the two orthogonal slopes of the out-of-plane deformation. In addition, the imaging lens and apertures are respectively placed in three optical paths to independently control the carrier frequencies and shearing amounts. The effectiveness of this method can be proved by measuring two pressure-loaded circular plates.
基金supported by grants from the National Key Research and Development Program of China(2022YFF1002903 to Y.W.)the Strategic Priority Research Program“Molecular Mechanism of Plant Growth and Development”of CAS(XDB27010100 to Y.W.)+1 种基金the National Natural Science Foundation of China(32372075 to L.H.)the Top Talents Program“One Case One Discussion”(Yishiyiyi to Y.W.)from Shandong Province。
文摘Rice tiller angle is a key agronomic trait that has significant effects on the establishment of a high-yield rice population.However,the molecular mechanism underlying the control of rice tiller angle remains to be clarified.Here,we characterized the novel tiller-angle gene LAZY4(LA4)in rice through map-based cloning.LA4 encodes a C3H2C3-type RING zinc-finger E3 ligase localized in the nucleus,and an in vitro ubiquitination assay revealed that the conserved RING finger domain is essential for its E3 ligase activity.We found that expression of LA4 can be induced by gravistimulation and that loss of LA4 function leads to defective shoot gravitropism caused by impaired asymmetric auxin redistribution upon gravistimulation.Genetic analysis demonstrated that LA4 acts in a distinct pathway from the starch biosynthesis regulators LA2 and LA3,which function in the starch-statolith-dependent pathway.Further genetic analysis showed that LA4 regulates shoot gravitropism and tiller angle by acting upstream of LA1 to mediate lateral auxin transport upon gravistimulation.Our studies reveal that LA4 regulates shoot gravitropism and tiller angle upstream of LA1 through a novel pathway independent of the LA2-LA3-mediated gravity-sensing mechanism,providing new insights into the rice tiller-angle regulatory network.
基金supported by the Laoshan laboratory(LSKJ202203206)National Natural Science Foundation of China(92051115 and 42230412)+1 种基金the Fundamental Research Funds for the Central Universities(202172002 and 202141009)the Shandong Province Natural Science Foundation(ZR2022YQ38).
文摘Hadal trenches are characterized by enhanced and infrequent high-rate episodic sedimentation events that likely introduce not only labile organic carbon and key nutrients but also new microbes that significantly alter the subseafloor microbiosphere.Currently,the role of high-rate episodic sedimentation in controlling the composition of the hadal subseafloor microbiosphere is unknown.Here,analyses of carbon isotope composition in a~750 cm long sediment core from the Challenger Deep revealed noncontinuous deposition,with anomalous ^(14)C ages likely caused by seismically driven mass transport and the funneling effect of trench geomorphology.Microbial community composition and diverse enzyme activities in the upper~27 cm differed from those at lower depths,probably due to sudden sediment deposition and differences in redox condition and organic matter availability.At lower depths,microbial population numbers,and composition remained relatively constant,except at some discrete depths with altered enzyme activity and microbial phyla abundance,possibly due to additional sudden sedimentation events of different magnitude.Evidence is provided of a unique role for high-rate episodic sedimentation events in controlling the subsurface microbiosphere in Earth’s deepest ocean floor and highlight the need to perform thorough analysis over a large depth range to characterize hadal benthic populations.Such depositional processes are likely crucial in shaping deep-water geochemical environments and thereby the deep subseafloor biosphere.
基金supported by the National Natural Science Foundation of China(Nos.52375536 and 52375535)the Key Research and Development Program of Jiangxi Province(No.20223BBE51010)。
文摘In this study,an innovative technique is introduced to significantly enhance the sensitivity of electronic speckle pattern interferometry(ESPI)for the dynamic assessment of specular(mirrorlike)object deformations.By utilizing a common-path illumination strategy,wherein illumination and observation beams are precisely aligned,this method effectively doubles the optical path difference,leading to a twofold increase in measurement sensitivity.In addition,this method mitigates the effects of speckle noise on the measurement of minor deformations,expanding the applications of ESPI.Theoretical and experimental evaluations corroborate the efficacy of this approach.
基金supported by the National Key Research and Development Program of China(2022YFC2304800)the Science and Technological Supports Project of Sichuan Province in China(2022YFS0094).
文摘Background and Aims:Acute liver failure(ALF)is a life-threatening clinical problem with limited treatment options.Administration of human umbilical cord mesenchymal stem cells(hUC-MSCs)may be a promising approach for ALF.This study aimed to explore the role of hUC-MSCs in the treat-ment of ALF and the underlying mechanisms.Methods:A mouse model of ALF was induced by lipopolysaccharide and d-galactosamine administration.The therapeutic effects of hUC-MSCs were evaluated by assessing serum enzyme activity,histological appearance,and cell apoptosis in liver tissues.The apoptosis rate was analyzed in AML12 cells.The levels of inflammatory cytokines and the phenotype of RAW264.7 cells co-cultured with hUC-MSCs were detected.The C-Jun N-terminal kinase/nuclear factor-kappa B signal-ing pathway was studied.Results:The hUC-MSCstreatment decreased the levels of serum alanine aminotransferase and aspartate aminotransferase,reduced pathological damage,alleviated hepatocyte apoptosis,and reduced mortality in vivo.The hUC-MSCs co-culture reduced the apoptosis rate of AML12 cells in vitro.Moreover,lipopolysaccharide-stimulated RAW264.7 cells had higher levels of tumor necrosis factor-α,interleukin-6,and interleukin-1β and showed more CD86-positive cells,whereas the hUC-MSCs co-culture reduced the levels of the three inflammatory cytokines and increased the ratio of CD206-positive cells.The hUC-MSCs treatment inhibited the activation of phosphorylated(p)-C-Jun N-terminal kinase and p-nuclear factor-kappa B not only in liver tissues but also in AML12and RAW264.7 cells co-cultured with hUC-MSCs.Conclusions:hUC-MSCs could alleviate ALF by regulating hepatocyte apoptosis and macrophage polarization,thus hUC-MSC-based cell therapy may be an alternative option for patients with ALF.
基金financially supported by a grant from the National High Technology Research and Development Program of China(863 program),No.2012AA021201the Major State Basic Research Development Program of China(973 program),No.2012CB721006+1 种基金National Major Scientific and Technological Special Project,No.2012YQ15008709Research Fund for the Doctoral Program of Higher Education of China,No.20110074110015.
文摘Background:An economical and integrated high-throughput primary screening strategy was developed for high-aerobic microbe Monascus purpureus cultivation.A novel and effective mixture culture method was proposed and used to realize the whole mutant library being high-throughput screened after mutagenesis.Results:The good correlation of fermentation results between differing-scale cultivations confirmed the feasibility of utilizing the 48-deep microtiter plates(MTPs)as a scale-down tool for culturing high-aerobic microbes.In addition,the fluid dynamics of 24-,48-,and 96-deep MTPs and 500-mL shake flask were studied respectively using the computational fluid dynamic(CFD)tool ANSYS CFX 11.0 to get better understanding of their turbulent regimes.Conclusions:The by-product citrinin production had no significant change while the pigment production had improved.As a result,the high-yield strain T33-6 was successfully screened out and the pigment was more than 50%higher than that of the parental strain in the shake flask.
基金supported by the grants from the National Natural Science Foundation of China (31788103,91635301).
文摘Tillering in rice is one of the most important agronomic traits.Rice tiller development can be divided into two main processes: the formation of the axillary bud and its subsequent outgrowth.Several genes critical for bud formation in rice have been identified by genetic studies;however,their molecular functions and relationships are still largely unknown.Here,we report that MONOCULM 1 (MOC1) and MONOCULM 3/ TILLERS ABSENT 1/STERILE AND REDUCED TILLERING 1 (MOC3/TAB1/SRT1),two vital regulators for tiller formation in rice,physically interact to regulate tiller bud outgrowth through upregulating the expression of FLORAL ORGAN NUMBER 1 (FON1),the homolog of CLAVATA1 in rice.We found that M0C3 is able to directly bind the promoter ofFONI and subsequently activate FON1 expression.MOC1 functions as a coactivator of MOC3,whereas it could not directly bind the FON1 promoter,and further activated FON1 expression in the presence of MOC3.Accordingly,FON1 is highly expressed at axillary meristems and shows remarkably decreased expression levels in mod and moc3 mutants.Loss-of-function mutants of FON1 exhibit normal bud formation but defective bud outgrowth and reduced tiller number.Collectively,these results shed light on a joint transcriptional regulatory mechanim by MOC1 and MOC3,and establish a new framework for the control of tiller bud formation and outgrowth.
基金supported by grants from the National Natural Science Foundation of China (9163530191535204+2 种基金31601276)the Ministry of Agriculture of China (2016ZX08009-003)the Strategic Priority Research Program "Molecular Mechanism of Plant Growth and Development" of CAS (XDPB0401).
文摘Rice tiller angle is a key agronomic trait that contributes to ideal plant architecture and grain production.LAZY1 (LA1) was previously shown to control tiller angle via affecting shoot gravitropism,but the underlying molecular mechanism remains largely unknown.In this study,we identified an LA1-interacting protein named Brevis Radix Like 4 (OsBRXL4).We showed that the interaction between OsBRXL4 and LA1 occurs at the plasma membrane and that their interaction determines nuclear localization of LA1.We found that nuclear localization of LA1 is essential for its function,which is different from AtLA1,its Arabidopsis ortho.log.Overexpression of OsBRXL4 leads to a prostrate growth phenotype,whereas OsBRXLs RNAi plants,in which the expression levels of OsBRXLI,OsBRXL4,and OsBRXL5 were decreased,display a compact phenotype.Further genetic analysis also supported that OsBRXL4 controls rice tiller angle by affecting nuclear localization of LA1.Consistently,we demonstrated that OsBRXL4 regulates the shoot gravitropism through affecting polar auxin transport as did LA1.Taken together,our study not only identifies OsBRXL4 as a regulatory component of rice tiller angle but also provides new insights into genetic regulation of rice plant architecture.
基金supported by grants from the National Natural Science Foundation of China (No.91335204)the Ministry of Science and Technology (No.2013CBA01401)
文摘WUSCHEL （WUS） plays an essential role for the maintenance of meristem activity in dicots, but its function is still elusive in monocots. We isolated a new monoculm mutant, monoculm 3 （moc3）, in which a point mutation causes the premature termination of rice O. sativa WUS （OsWUS）. Morphological observation revealed that the formation of tiller buds was disrupted in moc3. MOC3 was localized in the nuclear and could interact with TOPLESS-RELATED PROTEINS （TPRs）. The expression of MOC3 was induced by cytokinins and defection of MOC3 affected the expression of several two-component cytokinin response regulators, OsRRs and ORRs. Our results suggest that MOC3 is required for the formation of axillary buds and has a complex relationship with cytokinins.
基金grants from the Chinese Ministry of Science and Technology(2016YFD0100901)the Ministry of Agriculture of China(2016ZX08011001)+2 种基金the CAS President’s International Fellowship Initiative(2018VBA0025)the Youth Innovation Promotion Association CAS(2019099)the Strategic Priority Research Program of CAS(XDB27010100)(Beltran et al.,2015).
文摘Rice tillering is an important agronomic trait affecting grain yield.Here,we identified a high-tillering mutant tillering20(t20),which could be restored to the wild type by treatment with the strigolactone(SL)analog rac-GR24.T20 encodes a chloroplast ζ-carotene isomerase(Z-ISO),which is involved in the biosynthesis of ca-rotenoids and their metabolites,SL and abscisic acid(ABA).The t20 mutant has reduced SL and ABA,raising the question of how SL and ABA biosynthesis is coordinated,and whether they have overlapping functions in tillering.We discovered that rac-GR24 stimulated T20 expression and enhanced all-trans-p-carotene biosynthesis.Importantly,rac-GR24 also stimulated expression of Oryza sativa 9-CIS-EPOXY-CAROTENOID DIOXYGENASE 1(OsNCED1)through induction of Oryza sativa HOMEOBOX12(0sHOX12),promoting ABA biosynthesis in shoot base.On the other hand,ABA treatment significantly repressed SL biosynthesis and the ABA biosynthetic mutants displayed elevated SL biosynthesis.ABA treatment reduced the number of basal tillers in both t20 and wild-type plants.Furthermore,while ABA-deficient mu-tants aba1 and aba2 had the same number of basal tillers as wild type,they had more unproductive upper tillers at maturity.This work demonstrates complex interactions in the biosynthesis of carotenoid,SLs and ABA,and reveals a role for ABA in the regulation of rice tillering.
