Formation of somatic embryos from non-germline cells is unique to higher plants and can be manipulated in a variety of species. Previous studies revealed that overexpression of several Arabidopsis genes, including WUS...Formation of somatic embryos from non-germline cells is unique to higher plants and can be manipulated in a variety of species. Previous studies revealed that overexpression of several Arabidopsis genes, including WUSCHEL （WUS）/PLANT GROWTH ACTIVATOR6 （PGA6）, BABY BOOM, LEAFY COTYLEDON1 （LEC1）, and LEC2, is able to cause vegetative-to-embryonic transition or the formation of somatic embryos. Here, we report that a gain-offunction mutation in the Arabidopsis PGA37 gene, encoding the MYBI18 transcription factor, induced vegetative-toembryonic transition, the formation of somatic embryos from root explants, and an elevated LEC1 expression level. Double mutant analysis showed that WUS was not required for induction of somatic embryos by PGA37/MYB118. In addition, overexpression of MYBll5, a homolog of PGA37/MYB118, caused a pga37-like phenotype. A myb118 myb115 double mutant did not show apparent developmental abnormalities. Collectively, these results suggest that PGA37/ MYB118 and MYB115 promote vegetative-to-embryonic transition, through a signaling pathway independent of WUS.展开更多
A short root mutant ksrl with the Kasalath background was isolated from an EMS-mutagenized population in rice. The root length of 6-day-old ksr1 seedlings was only about 20% of the wild type. Genetic analysis indicate...A short root mutant ksrl with the Kasalath background was isolated from an EMS-mutagenized population in rice. The root length of 6-day-old ksr1 seedlings was only about 20% of the wild type. Genetic analysis indicated that the short root phenotype of ksrl was controlled by a recessive mutation in a single nuclear-encoded gene. To map the ksrl mutation, an F2 population was generated by crossing the ksrl mutant with Nipponbare. The KSR1 locus was linked to the SSR marker RM1223 on rice chromosome 4. Eight new SSR markers and two InDel markers were developed around this marker. KSR1 gene was further mapped to a 155 kb region, flanked by the InDel marker 4-24725K and the SSR marker RM17182.展开更多
Over the past 10 years significant advances have been made towards the description of genetics and molecular mechanisms controlling grapevine berry growth. Regardless of this, many aspects of early fruit morphogenesis...Over the past 10 years significant advances have been made towards the description of genetics and molecular mechanisms controlling grapevine berry growth. Regardless of this, many aspects of early fruit morphogenesis and its development control remain to be elucidated. In an attempt to understand gene expression patterns associated with the berry growth development, the contrasting phenotype between the cv. Isabel (Vitis labrusca L.) and its early berry development mutant “Isabel Precoce” has been explored by a candidate gene approach. “Isabel Precoce” (Vitis labrusca L.) was confirmed as an EDV (Essentially Derived Variety) of Isabel, with a 30-35-day reduction in the berry growth phase when compared to the wild type and thus, it constitutes an informative model to investigate many aspects of fruit growth and development. Phenotypic analysis showed that “Isabel Precoce” develops fruits that are smaller in diameter and volume despite of following similar development kinetics. The expression of many genes associated with plant growth and development (MIKCC-type MADS box genes), sugar transport and with the control of flavonoid biosynthetic pathway have been evaluated. The majority of the genes presented a remarkably similar transcription profile. However, a higher induction of transcript accumulation for some genes has been observed in the “Isabel Precoce” genetic background.展开更多
Phytohormone, ethylene plays an important role in plant growth and development including fruit ripening and flower senescence. The synthesis of 1-aminocylo-propane-1- carboxylate (ACC), the immediate precursor of ethy...Phytohormone, ethylene plays an important role in plant growth and development including fruit ripening and flower senescence. The synthesis of 1-aminocylo-propane-1- carboxylate (ACC), the immediate precursor of ethylene, from S-adenosyl-methionine is catalyzed by ACC synthase;and which is also a rate limiting step in the ethylene biosynthetic pathway. Therefore, it plays a key role in ethylene biosynthesis and the genes that code for ACC synthase are of special interest. Moreover, in zonal geraniums, ethylene bursts released from cuttings can have profound impact on the viability of explants for plant propagation. Biotechnological approach involving genetic modification that may reduce ethylene levels has potential for increasing the shelf-life of cuttings for plant propagation. These considerations have led us to clone several cDNA of ACC synthase genes from Pelargonium x hortorum cv. ?‘Sincerity’. To transform geranium cells with Agrobacterium tumefaciens an in vitro regeneration? system was developed using very young petiole explants. An Antisense construct of ACC synthase cDNA (PHSacc41) ligated into binary vector pAM696 was introduced into A. tumefaciens EHA 105 cells. Petiole explants were incubated with the Agrobacterium for 15 min and then co-cultivated for several days on MS medium containing 5 mM BAP and ?1 mM IAA in? the dark without the antibiotics. Selection for transformants was carried out in the presence of kanamycin and timentin. Transgenic plantlets generated were examined for inserted gene cassette by PCR and Southern blotting. Recovery of positive transformants that survived selection suggested that it is possible to transform and introduce genes via transformation in hybrid geraniums for genetic modification.展开更多
In the present investigation the structural proteins associated with MAC-1 bacteriophage have been characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE);tandem mass spectrometry of p...In the present investigation the structural proteins associated with MAC-1 bacteriophage have been characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE);tandem mass spectrometry of protein bands from SDS-PAGE gel;from the open reading frames (ORFs) deduced from MAC-1 genome sequence and amino acid sequence homology searches from the Uniprot database (up000002418). Results have led to the identification of at least three structural proteins associated with MAC-1 phage genome. They are: capsid protein (~55,000-daltons);spike protein (~22,000-daltons) and a low molecular weight DNA binding protein (~4000-dal- tons). In addition, two other minor proteins were tentatively identified as replicative and scaffold proteins based on two to three unique peptides from mass spectrometry data. However, other proteins coded (ORFs) by phage genome remain to be identified.展开更多
rd29A gene of Arabidopsis encodes a LEA-like hydrophilic protein, its expression is induced by drought, high-salt and cold stress. In the promoter region of rd29A gene, there are 2 ORE cis-acting elements involved in ...rd29A gene of Arabidopsis encodes a LEA-like hydrophilic protein, its expression is induced by drought, high-salt and cold stress. In the promoter region of rd29A gene, there are 2 ORE cis-acting elements involved in responses to these environmental stresses. 5 cDNAs (DREB1A-C and DREB2A-B) encoding DREB transcription factors, which specifically bind to ORE element and control the expression of reporter gene under drought, high-salt and stress, have been isolated by One-Hybrid screening method and with ORE element of rd29A promoter. DREB transcription factors and ORE element function in signal transduction of drought, high-salt and cold stress. One DREB transcription factor can control the expression of several target functional genes involved in plant tolerance to drought, high-salt and cold stress. Thus, it may be an effective strategy to achieve ideal, multiple and fundamental effect for improving plant stress-resistance by DREB gene transfer.展开更多
Malate dehydrogenase（MDH） is a key enzyme that catalyzes the reversible oxidation of oxaloacetate to malate and plays an important role in the physiological processes of plant growth and development. However, cyto- ...Malate dehydrogenase（MDH） is a key enzyme that catalyzes the reversible oxidation of oxaloacetate to malate and plays an important role in the physiological processes of plant growth and development. However, cyto- solic malate dehydrogenase（cMDH）, which is crucial for malate synthesis in the cytosol, still has not been extensively characterized in plants. Here, we isolated a cytosolic malate dehydrogenase gene, designated as GhcMDH1, from Gossypium hirsutum and characterized its possible molecular function in cotton fiber. The cloned cDNA of GhcMDH1 is 1520 base pairs in length, and has an open reading frame of 999 base pairs, encoding for 332 amino acid residues with an estimated molecular weight of 35580 and pI of 6.35. Sequence alignment showed that the de- duced amino acid sequence of GhcMDH1 protein shared a high similarity to other plant cMDHs. Confocal and im- munological analysis confirmed that GhcMDH1 protein was subcellularly localized to the cytosol. Quantitative real-time polymerase chain reaction（PCR） revealed that GhcMDH1 was constitutively expressed in all vegetative cotton tissues, with slightly lower levels in roots than stems and leaves. Interestingly, the transcripts of GhcMDH1 were detected in 5--25 d post anthesis（DPA） fibers and highly abundant at 15 DPA fibers. The total MDH activities and malate contents of cotton fibers were positively correlated with the fiber elongation rates, suggesting that GhcMDH1 may function in malate synthesis in fast fiber elongation. In agreement with this suspicion, the recombi- nant His-GhcMDH1 protein mainly drives the reaction towards malate generation in vitro. In conclusion, our mole- cular characterization of the GhcMDH1 gene provides valuable insights to further investigate the malate equilibrium in cotton fiber development.展开更多
The plant phospholipase D （PLD） plays versatile functions in multiple aspects of plant growth, development, and stress re- sponses. However, until now, our knowledge concerning the PLD gene family members and their ...The plant phospholipase D （PLD） plays versatile functions in multiple aspects of plant growth, development, and stress re- sponses. However, until now, our knowledge concerning the PLD gene family members and their expression patterns in cotton has been limited. In this study, we performed for the first time the genome-wide analysis and expression profiling of PLD gene family in Gossypium arboretum, and finally, a total of 19 non-redundant PLD genes （GaPLDs） were identified. Based on the phylogenetic analysis, they were divided into six well-supported clades （tx, 13/？, 8, ~, ~ and q~）. Most of the GaPLD genes with- in the same clade showed the similar exon-intron organization and highly conserved motif structures. Additionally, the chro- mosomal distribution pattern revealed that GaPLD genes were unevenly distributed across 10 of the 13 cotton chromosomes. Segmental duplication is the major contributor to the expansion of GaPLD gene family and estimated to have occurred from 19.61 to 20.44 million years ago when a recent large-scale genome duplication occurred in cotton. Moreover, the expression profiling provides the functional divergence of GaPLD genes in cotton and provides some new light on the molecular mecha- nisms of GaPLDcd and GaPLD62 in fiber development.展开更多
Micro RNAs(mi RNAs) have been shown to play critical regulatory roles in gene expression in cotton. Although a large number of mi RNAs have been identified in cotton fibers, the functions of mi RNAs in seed developmen...Micro RNAs(mi RNAs) have been shown to play critical regulatory roles in gene expression in cotton. Although a large number of mi RNAs have been identified in cotton fibers, the functions of mi RNAs in seed development remain unexplored. In this study, a small RNA library was constructed from cotton seeds sampled at 15 days post-anthesis(DPA) and was subjected to high-throughput sequencing. A total of 95 known mi RNAs were detected to be expressed in cotton seeds. The expression pattern of these identified mi RNAs was profiled and 48 known mi RNAs were differentially expressed between cotton seeds and fibers at 15 DPA. In addition, 23 novel mi RNA candidates were identified in 15-DPA seeds. Putative targets for 21 novel and 87 known mi RNAs were successfully predicted and 900 expressed sequence tag(EST) sequences were proposed to be candidate target genes, which are involved in various metabolic and biological processes, suggesting a complex regulatory network in developing cotton seeds. Furthermore, mi RNA-mediated cleavage of three important transcripts in vivo was validated by RLM-5′ RACE. This study is the first to show the regulatory network of mi RNAs that are involved in developing cotton seeds and provides a foundation for future studies on the specific functions of these mi RNAs in seed development.展开更多
Dendrobium candidum, a wild orchid species from China, normally requires three to four years of cultivation before it can produce flowers. The effects of plant hormones and polyamines on flower initiation of this spec...Dendrobium candidum, a wild orchid species from China, normally requires three to four years of cultivation before it can produce flowers. The effects of plant hormones and polyamines on flower initiation of this species in tissue culture were investigated. The addition of spermidine, or BA, or the combination of NAA and BA to the culture medium can induce protocorms or shoots to flower within three to six months with a frequency of 31.6% -45.8%. The flowering frequency can be further increased to 82.8 % on the average by pre-treatment of protocorms in an ABA-containing medium followed by transfer onto MS medium with BA. The induction of precocious flowering de-pends on the developmental stage of the experimental materials (protocorms, shoots and plantlets) used , and usually occurs only when root formation is inhibited.展开更多
Abscisic acid （ABA） plays crucial roles in plant growth and development, as well as in response to various environmental stresses. To date, many regulatory genes involved in the ABA response network have been identi...Abscisic acid （ABA） plays crucial roles in plant growth and development, as well as in response to various environmental stresses. To date, many regulatory genes involved in the ABA response network have been identified; however, their roles have remained to be fully elucidated. In this study, we iden- tified AtYY1, an Arabidopsis homolog of the mammalian C2H2 zinc-finger transcription factor Yin Yang 1 （YY1）, as a novel negative regulator of the ABA response. AtYY1 is a dual-function transcription factor with both repression and activation domains. The expression of AtYY1 was induced by ABA and stress conditions including high salt and dehydration. The yyl mutant was more sensitive to ABA and NaCI than the wild-type, while overexpressing AtYY1 plants were less sensitive. AtYY1 loss also enhanced ABA-induced stomatal closing and drought resistance. Moreover, AtYYI can bind the ABA REPRESSOR1 （ABR1） promoter and directly upregulate ABR1 expression, as well as negatively regulate ABA- and saR-responsive gene expression. Additional analysis indicated that ABA INSENSITIVE4 （ABI4） might positively regulate AtYY1 expression and that ABR1 can antagonize this regulation. Our findings provide direct evidence that AtYY1 is a novel negative regulator of the ABA response network and that the ABI4-AtYY1-ABR1 regulatory pathway may fine-tune ABA-responsive gene expression in Arabidopsis.展开更多
Phospholipase C (PLC) are important regulatory enzymes involved in several lipid and Ca2+-dependent signaling pathways.Previous studies have elucidated the versatile roles of PLC genes in growth, development and stres...Phospholipase C (PLC) are important regulatory enzymes involved in several lipid and Ca2+-dependent signaling pathways.Previous studies have elucidated the versatile roles of PLC genes in growth, development and stress responses of many plants, however, the systematic analyses of PLC genes in the important fiber-producing plant, cotton, are still deficient. In this study,through genome-wide survey, we identified twelve phosphatidylinositol-specific PLC (PI-PLC) and nine non-specific PLC (NPC) genes in the allotetraploid upland cotton Gossypium hirsutum and nine PI-PLC and six NPC genes in two diploid cotton G. arboretum and G.raimondii, respectively. The PI-PLC and NPC genes of G. hirsutum showed close phylogenetic relationship with their homologous genes in the diploid cottons and Arabidopsis. Segmental and tandem duplication contributed greatly to the formation of the gene family. Expression profiling indicated that few of the PLC genes are constitutely expressed, whereas most of the PLC genes are preferentially expressed in specific tissues and abiotic stress conditions. Promoter analyses further implied that the expression of these PLC genes might be regulated by MYB transcription factors and different phytohormones.These results not only suggest an important role of phospholipase C members in cotton plant development and abiotic stress response but also provide good candidate targets for future molecular breeding of superior cotton cultivars.展开更多
Upland cotton （Gossypium hirsutum L.） is an allotetraploid species originated from interspecific hybridization between AA-genome diploid （G. arboretum） and DD-genome diploid （G. raimondii） （Wendel et al., 1992...Upland cotton （Gossypium hirsutum L.） is an allotetraploid species originated from interspecific hybridization between AA-genome diploid （G. arboretum） and DD-genome diploid （G. raimondii） （Wendel et al., 1992）. Cotton fibers are single-celled trichomes that emerge from the ovule epidermal cells. Indexed by the number of days post-anthesis （dpa）, fiber morphogenesis includes four distinct but overlapping steps： initiation （0-3 dpa）, elongation （3-20 dpa）, secondary cell wall thickening （15-45 dpa） and maturation （40-60 dpa） （Yang et al., 2008, Du et al., 2013）. The efficiency and duration of each morphogenesis stage is important to the quality attributes of the mature fiber. Cell elongation is critical for fiber length, whereas secondary cell wall thickening is important for fiber fineness and strength （Meinert and Delmer, 1977）.展开更多
Dear Editor, In recent years, the proteomics field has been trans- formed from charting static proteomes to examining their dynamics by simultaneously quantifying multiple proteins from different experimental samples...Dear Editor, In recent years, the proteomics field has been trans- formed from charting static proteomes to examining their dynamics by simultaneously quantifying multiple proteins from different experimental samples. Accurate quantifica- tion of differences in protein expression levels is essential for comparative proteomics and is becoming an integral and important part of modern experimental biological science （Simicevic et al., 2013）. Advanced mass spectrom- etry （MS） provides a powerful means for achieving quan- titative proteomics data.展开更多
文摘Formation of somatic embryos from non-germline cells is unique to higher plants and can be manipulated in a variety of species. Previous studies revealed that overexpression of several Arabidopsis genes, including WUSCHEL （WUS）/PLANT GROWTH ACTIVATOR6 （PGA6）, BABY BOOM, LEAFY COTYLEDON1 （LEC1）, and LEC2, is able to cause vegetative-to-embryonic transition or the formation of somatic embryos. Here, we report that a gain-offunction mutation in the Arabidopsis PGA37 gene, encoding the MYBI18 transcription factor, induced vegetative-toembryonic transition, the formation of somatic embryos from root explants, and an elevated LEC1 expression level. Double mutant analysis showed that WUS was not required for induction of somatic embryos by PGA37/MYB118. In addition, overexpression of MYBll5, a homolog of PGA37/MYB118, caused a pga37-like phenotype. A myb118 myb115 double mutant did not show apparent developmental abnormalities. Collectively, these results suggest that PGA37/ MYB118 and MYB115 promote vegetative-to-embryonic transition, through a signaling pathway independent of WUS.
基金supported by the Science and Technology Development of Zhejiang Province, China (Grant No. Z306401)the Science and Technology Foundation of Ningbo, China (Grant No. 2008A610070)Wong Kuancheng Education Foundation
文摘A short root mutant ksrl with the Kasalath background was isolated from an EMS-mutagenized population in rice. The root length of 6-day-old ksr1 seedlings was only about 20% of the wild type. Genetic analysis indicated that the short root phenotype of ksrl was controlled by a recessive mutation in a single nuclear-encoded gene. To map the ksrl mutation, an F2 population was generated by crossing the ksrl mutant with Nipponbare. The KSR1 locus was linked to the SSR marker RM1223 on rice chromosome 4. Eight new SSR markers and two InDel markers were developed around this marker. KSR1 gene was further mapped to a 155 kb region, flanked by the InDel marker 4-24725K and the SSR marker RM17182.
文摘Over the past 10 years significant advances have been made towards the description of genetics and molecular mechanisms controlling grapevine berry growth. Regardless of this, many aspects of early fruit morphogenesis and its development control remain to be elucidated. In an attempt to understand gene expression patterns associated with the berry growth development, the contrasting phenotype between the cv. Isabel (Vitis labrusca L.) and its early berry development mutant “Isabel Precoce” has been explored by a candidate gene approach. “Isabel Precoce” (Vitis labrusca L.) was confirmed as an EDV (Essentially Derived Variety) of Isabel, with a 30-35-day reduction in the berry growth phase when compared to the wild type and thus, it constitutes an informative model to investigate many aspects of fruit growth and development. Phenotypic analysis showed that “Isabel Precoce” develops fruits that are smaller in diameter and volume despite of following similar development kinetics. The expression of many genes associated with plant growth and development (MIKCC-type MADS box genes), sugar transport and with the control of flavonoid biosynthetic pathway have been evaluated. The majority of the genes presented a remarkably similar transcription profile. However, a higher induction of transcript accumulation for some genes has been observed in the “Isabel Precoce” genetic background.
文摘Phytohormone, ethylene plays an important role in plant growth and development including fruit ripening and flower senescence. The synthesis of 1-aminocylo-propane-1- carboxylate (ACC), the immediate precursor of ethylene, from S-adenosyl-methionine is catalyzed by ACC synthase;and which is also a rate limiting step in the ethylene biosynthetic pathway. Therefore, it plays a key role in ethylene biosynthesis and the genes that code for ACC synthase are of special interest. Moreover, in zonal geraniums, ethylene bursts released from cuttings can have profound impact on the viability of explants for plant propagation. Biotechnological approach involving genetic modification that may reduce ethylene levels has potential for increasing the shelf-life of cuttings for plant propagation. These considerations have led us to clone several cDNA of ACC synthase genes from Pelargonium x hortorum cv. ?‘Sincerity’. To transform geranium cells with Agrobacterium tumefaciens an in vitro regeneration? system was developed using very young petiole explants. An Antisense construct of ACC synthase cDNA (PHSacc41) ligated into binary vector pAM696 was introduced into A. tumefaciens EHA 105 cells. Petiole explants were incubated with the Agrobacterium for 15 min and then co-cultivated for several days on MS medium containing 5 mM BAP and ?1 mM IAA in? the dark without the antibiotics. Selection for transformants was carried out in the presence of kanamycin and timentin. Transgenic plantlets generated were examined for inserted gene cassette by PCR and Southern blotting. Recovery of positive transformants that survived selection suggested that it is possible to transform and introduce genes via transformation in hybrid geraniums for genetic modification.
文摘In the present investigation the structural proteins associated with MAC-1 bacteriophage have been characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE);tandem mass spectrometry of protein bands from SDS-PAGE gel;from the open reading frames (ORFs) deduced from MAC-1 genome sequence and amino acid sequence homology searches from the Uniprot database (up000002418). Results have led to the identification of at least three structural proteins associated with MAC-1 phage genome. They are: capsid protein (~55,000-daltons);spike protein (~22,000-daltons) and a low molecular weight DNA binding protein (~4000-dal- tons). In addition, two other minor proteins were tentatively identified as replicative and scaffold proteins based on two to three unique peptides from mass spectrometry data. However, other proteins coded (ORFs) by phage genome remain to be identified.
文摘rd29A gene of Arabidopsis encodes a LEA-like hydrophilic protein, its expression is induced by drought, high-salt and cold stress. In the promoter region of rd29A gene, there are 2 ORE cis-acting elements involved in responses to these environmental stresses. 5 cDNAs (DREB1A-C and DREB2A-B) encoding DREB transcription factors, which specifically bind to ORE element and control the expression of reporter gene under drought, high-salt and stress, have been isolated by One-Hybrid screening method and with ORE element of rd29A promoter. DREB transcription factors and ORE element function in signal transduction of drought, high-salt and cold stress. One DREB transcription factor can control the expression of several target functional genes involved in plant tolerance to drought, high-salt and cold stress. Thus, it may be an effective strategy to achieve ideal, multiple and fundamental effect for improving plant stress-resistance by DREB gene transfer.
文摘Malate dehydrogenase（MDH） is a key enzyme that catalyzes the reversible oxidation of oxaloacetate to malate and plays an important role in the physiological processes of plant growth and development. However, cyto- solic malate dehydrogenase（cMDH）, which is crucial for malate synthesis in the cytosol, still has not been extensively characterized in plants. Here, we isolated a cytosolic malate dehydrogenase gene, designated as GhcMDH1, from Gossypium hirsutum and characterized its possible molecular function in cotton fiber. The cloned cDNA of GhcMDH1 is 1520 base pairs in length, and has an open reading frame of 999 base pairs, encoding for 332 amino acid residues with an estimated molecular weight of 35580 and pI of 6.35. Sequence alignment showed that the de- duced amino acid sequence of GhcMDH1 protein shared a high similarity to other plant cMDHs. Confocal and im- munological analysis confirmed that GhcMDH1 protein was subcellularly localized to the cytosol. Quantitative real-time polymerase chain reaction（PCR） revealed that GhcMDH1 was constitutively expressed in all vegetative cotton tissues, with slightly lower levels in roots than stems and leaves. Interestingly, the transcripts of GhcMDH1 were detected in 5--25 d post anthesis（DPA） fibers and highly abundant at 15 DPA fibers. The total MDH activities and malate contents of cotton fibers were positively correlated with the fiber elongation rates, suggesting that GhcMDH1 may function in malate synthesis in fast fiber elongation. In agreement with this suspicion, the recombi- nant His-GhcMDH1 protein mainly drives the reaction towards malate generation in vitro. In conclusion, our mole- cular characterization of the GhcMDH1 gene provides valuable insights to further investigate the malate equilibrium in cotton fiber development.
基金the State Key Basic Research and Development Plan (2010CB126003)the National Transgenic Animals and Plants Research Project (2011ZX08005-003, 2011ZX08009-003)
文摘The plant phospholipase D （PLD） plays versatile functions in multiple aspects of plant growth, development, and stress re- sponses. However, until now, our knowledge concerning the PLD gene family members and their expression patterns in cotton has been limited. In this study, we performed for the first time the genome-wide analysis and expression profiling of PLD gene family in Gossypium arboretum, and finally, a total of 19 non-redundant PLD genes （GaPLDs） were identified. Based on the phylogenetic analysis, they were divided into six well-supported clades （tx, 13/？, 8, ~, ~ and q~）. Most of the GaPLD genes with- in the same clade showed the similar exon-intron organization and highly conserved motif structures. Additionally, the chro- mosomal distribution pattern revealed that GaPLD genes were unevenly distributed across 10 of the 13 cotton chromosomes. Segmental duplication is the major contributor to the expansion of GaPLD gene family and estimated to have occurred from 19.61 to 20.44 million years ago when a recent large-scale genome duplication occurred in cotton. Moreover, the expression profiling provides the functional divergence of GaPLD genes in cotton and provides some new light on the molecular mecha- nisms of GaPLDcd and GaPLD62 in fiber development.
基金supported by the National Basic Research Program of China(2010CB126003)the National Transgenic Animals and Plants Research Project(2011ZX08005-003,2011ZX08009-003)
文摘Micro RNAs(mi RNAs) have been shown to play critical regulatory roles in gene expression in cotton. Although a large number of mi RNAs have been identified in cotton fibers, the functions of mi RNAs in seed development remain unexplored. In this study, a small RNA library was constructed from cotton seeds sampled at 15 days post-anthesis(DPA) and was subjected to high-throughput sequencing. A total of 95 known mi RNAs were detected to be expressed in cotton seeds. The expression pattern of these identified mi RNAs was profiled and 48 known mi RNAs were differentially expressed between cotton seeds and fibers at 15 DPA. In addition, 23 novel mi RNA candidates were identified in 15-DPA seeds. Putative targets for 21 novel and 87 known mi RNAs were successfully predicted and 900 expressed sequence tag(EST) sequences were proposed to be candidate target genes, which are involved in various metabolic and biological processes, suggesting a complex regulatory network in developing cotton seeds. Furthermore, mi RNA-mediated cleavage of three important transcripts in vivo was validated by RLM-5′ RACE. This study is the first to show the regulatory network of mi RNAs that are involved in developing cotton seeds and provides a foundation for future studies on the specific functions of these mi RNAs in seed development.
文摘Dendrobium candidum, a wild orchid species from China, normally requires three to four years of cultivation before it can produce flowers. The effects of plant hormones and polyamines on flower initiation of this species in tissue culture were investigated. The addition of spermidine, or BA, or the combination of NAA and BA to the culture medium can induce protocorms or shoots to flower within three to six months with a frequency of 31.6% -45.8%. The flowering frequency can be further increased to 82.8 % on the average by pre-treatment of protocorms in an ABA-containing medium followed by transfer onto MS medium with BA. The induction of precocious flowering de-pends on the developmental stage of the experimental materials (protocorms, shoots and plantlets) used , and usually occurs only when root formation is inhibited.
基金This work was financially supported by grants from the National Transgenic Animals ＆ Plants Research Project （2009ZX08009-069B, 2013ZX08009-003）, the State Key Basic Research and Development Plan （2010CB126003）, and the China Postdoctoral Science Foundation （20080430370）.
文摘Abscisic acid （ABA） plays crucial roles in plant growth and development, as well as in response to various environmental stresses. To date, many regulatory genes involved in the ABA response network have been identified; however, their roles have remained to be fully elucidated. In this study, we iden- tified AtYY1, an Arabidopsis homolog of the mammalian C2H2 zinc-finger transcription factor Yin Yang 1 （YY1）, as a novel negative regulator of the ABA response. AtYY1 is a dual-function transcription factor with both repression and activation domains. The expression of AtYY1 was induced by ABA and stress conditions including high salt and dehydration. The yyl mutant was more sensitive to ABA and NaCI than the wild-type, while overexpressing AtYY1 plants were less sensitive. AtYY1 loss also enhanced ABA-induced stomatal closing and drought resistance. Moreover, AtYYI can bind the ABA REPRESSOR1 （ABR1） promoter and directly upregulate ABR1 expression, as well as negatively regulate ABA- and saR-responsive gene expression. Additional analysis indicated that ABA INSENSITIVE4 （ABI4） might positively regulate AtYY1 expression and that ABR1 can antagonize this regulation. Our findings provide direct evidence that AtYY1 is a novel negative regulator of the ABA response network and that the ABI4-AtYY1-ABR1 regulatory pathway may fine-tune ABA-responsive gene expression in Arabidopsis.
基金supported by the State Key Basic Research and Development Plan (2010CB126003)the National Transgenic Animals and Plants Research Project (2011ZX08005-003, 2011ZX08009-003)
文摘Phospholipase C (PLC) are important regulatory enzymes involved in several lipid and Ca2+-dependent signaling pathways.Previous studies have elucidated the versatile roles of PLC genes in growth, development and stress responses of many plants, however, the systematic analyses of PLC genes in the important fiber-producing plant, cotton, are still deficient. In this study,through genome-wide survey, we identified twelve phosphatidylinositol-specific PLC (PI-PLC) and nine non-specific PLC (NPC) genes in the allotetraploid upland cotton Gossypium hirsutum and nine PI-PLC and six NPC genes in two diploid cotton G. arboretum and G.raimondii, respectively. The PI-PLC and NPC genes of G. hirsutum showed close phylogenetic relationship with their homologous genes in the diploid cottons and Arabidopsis. Segmental and tandem duplication contributed greatly to the formation of the gene family. Expression profiling indicated that few of the PLC genes are constitutely expressed, whereas most of the PLC genes are preferentially expressed in specific tissues and abiotic stress conditions. Promoter analyses further implied that the expression of these PLC genes might be regulated by MYB transcription factors and different phytohormones.These results not only suggest an important role of phospholipase C members in cotton plant development and abiotic stress response but also provide good candidate targets for future molecular breeding of superior cotton cultivars.
基金supported by the grants from the State Key Basic Research and Development Plan (No. 2010CB126003)the National Transgenic Animals and Plants Research Project (Nos. 2011ZX08005-003 and 2011ZX08009-003)
文摘Upland cotton （Gossypium hirsutum L.） is an allotetraploid species originated from interspecific hybridization between AA-genome diploid （G. arboretum） and DD-genome diploid （G. raimondii） （Wendel et al., 1992）. Cotton fibers are single-celled trichomes that emerge from the ovule epidermal cells. Indexed by the number of days post-anthesis （dpa）, fiber morphogenesis includes four distinct but overlapping steps： initiation （0-3 dpa）, elongation （3-20 dpa）, secondary cell wall thickening （15-45 dpa） and maturation （40-60 dpa） （Yang et al., 2008, Du et al., 2013）. The efficiency and duration of each morphogenesis stage is important to the quality attributes of the mature fiber. Cell elongation is critical for fiber length, whereas secondary cell wall thickening is important for fiber fineness and strength （Meinert and Delmer, 1977）.
基金This work was supported by grants from the State Key Basic Research and Development Plan （2010CB126003）, the National Natural Science Foundation of China （90608016）, and the National Transgenic Animals and Plants Research Project （2009ZX08009-069B, 2011ZX08005-003, and 2011ZX08009-003）.
文摘Dear Editor, In recent years, the proteomics field has been trans- formed from charting static proteomes to examining their dynamics by simultaneously quantifying multiple proteins from different experimental samples. Accurate quantifica- tion of differences in protein expression levels is essential for comparative proteomics and is becoming an integral and important part of modern experimental biological science （Simicevic et al., 2013）. Advanced mass spectrom- etry （MS） provides a powerful means for achieving quan- titative proteomics data.
