Black rot, caused by Xanthomonas campestris pv. campestris (Xcc) is possibly the most important disease of Brassica worldwide. To compare chromosomal positions of Xcc resistance loci in Brassica oleracea between the p...Black rot, caused by Xanthomonas campestris pv. campestris (Xcc) is possibly the most important disease of Brassica worldwide. To compare chromosomal positions of Xcc resistance loci in Brassica oleracea between the present and published studies and to develop marker assisted selection (MAS) to resistance against Xcc race 1, we constructed a B. oleracea map, including pW, pX and BoCL markers that were closely linked to previously reported Xcc resistance QTLs. We also analyzed Xcc resistance QTLs by improving our previously reported map derived from the cross of a susceptible double-haploid line (GC P09) with a resistant double-haploid line (Reiho P01). In the nine linkage groups obtained (C1-C9), the major QTL, XccBo(Reiho)2, was derived from Reiho with a maximum LOD score (7.7) in C8. The QTL (LOD 4.4) located in C9, XccBo(GC)1 was derived from the susceptible GC. The other QTL (LOD 4.4), XccBo(Reiho)1, was found in C5. Based on common markers, it was possible to compare our finding Xcc resistance QTLs with the B. oleraceaXcc loci reported by previous authors;XccBo(Reiho)1 and XccBo(GC)1 may be identical to the Xcc resistance QTLs reported previously or a different member contained in the same resistance gene cluster. Our map includes public SSR markers linked to Xcc resistance genes that will promote pyramiding Xcc resistance genes in B. oleracea. The present study will also contribute to a better understanding of genetic control of Xcc resistance.展开更多
A phytotoxin from Xanthomonas campestris pv. retroflexus was isolated using a chromatographer and HPLC, and the components were identified to be a mixture of minor molecular compounds including organic acids and cyclo...A phytotoxin from Xanthomonas campestris pv. retroflexus was isolated using a chromatographer and HPLC, and the components were identified to be a mixture of minor molecular compounds including organic acids and cyclo-（proline-phenylalanine）. The greenhouse cultivation test was used to determine the influence of the isolated fractions on the growth of target weed redroot pigweed （Amaranthus retroflexus L）. The experimental results demonstrated that the cyclo-（Pro-Phe） had the weed inhibit activity obviously on dicotyledonous weed and the mixture with six organic acids showed stronger bioactivity. Further, greenhouse and field test were processed, and the test showed that the use of the toxin appeared to have the potential to be developed further as a bioherbicide system to control weedy grasses.展开更多
Cassava bacterial blight (CBB) caused by Xanthomonas axonopodis pv. manihotis has been reported in several African countries since 1970. Knowledge of the virulence and diversity of Xanthomonas axonopodis pv. manihotis...Cassava bacterial blight (CBB) caused by Xanthomonas axonopodis pv. manihotis has been reported in several African countries since 1970. Knowledge of the virulence and diversity of Xanthomonas axonopodis pv. manihotis strains is important for an integrated control of CBB. The main objective of the present study was to characterize strains of Xanthomonas axonopodis collected from various regions in the DR-Congo. There was variability among strains for shape (form), contour (margin) and elevation. Bacterial cell size for the strains analyzed varied from 24.1 μm × 11.3 μm to 11.4 μm × 4.2 μm. All the Xanthomonas axonopodis pv. manihotis strains but one was motile. Two distinctive groups were identified based on radial growth of their colonies. The first group grows faster (7.8-10.5 mm/d) compared to the second group (4.8-6.9 mm/d). Five strains (Gandajika, Inera/Stat, Kansasa, Mulumba and Musakatshi) were classified as virulent with a damage rating ≤ 1 and four were aggressive (Luputa, M'vuazi, Boketa and Kiyaka) with a damage rating > 1. Significant differences were also observed among strains for disease onset, incidence and plant mortality. The highest incidence (33%) of bacterial blight 21 days after infestation (DAI) resulted from the Boketa strain inoculation and the lowest (0 % disease incidence) from INERA/STAT and Musakatshi strains. There was no clear association between geographic origin of the strains and their aggressiveness.展开更多
Bacterial spot(BS)is a severe bacterial disease induced by Xanthomonas campestris pv.vesicatoria(Xcv),a pathogen that causes serious damage to pepper growth and yield.It is therefore important to study the mechanisms ...Bacterial spot(BS)is a severe bacterial disease induced by Xanthomonas campestris pv.vesicatoria(Xcv),a pathogen that causes serious damage to pepper growth and yield.It is therefore important to study the mechanisms of pepper resistance to Xcv and to breed and promote Xcvresistant pepper varieties.However,studies of the responses to Xcv infection in peppers at the protein level are limited.Here,we examined Xcv-induced proteomic changes in leaves of the BS susceptible bell pepper ECW and the resistant bell pepper VI037601 using the isobaric tags for relative and absolute quantitation(iTRAQ)-based protein labeling technology.A total of 6,120 distinct proteins were identified,and there were 1,289 significantly differentially accumulated proteins(DAPs)in ECW and VI037601 leaves after Xcv inoculation.Among these,339(250up-and 89 down-regulated)and 479(300 up-and 179 down-regulated)DAPs were specifically identified in ECW and VI037601,respectively,with 459(364 up-and 95 down-regulated)similarly expressed DAPs being shared by ECW and VI037601.Based on bioinformatics analysis,many defense-associated proteins were identified as up-regulated in ECW and VI037601,especially the proteins involved in plant-pathogen interaction,phenylpropanoid biosynthesis,protein processing in the endoplasmic reticulum,and MAPK signaling pathway-plant.Moreover,we evaluated transcript levels of six differentially expressed genes from the iTRAQ results by q RT-PCR.The analysis revealed transcriptional changes that were consistent with the changes at the protein level.This study will provide a valuable resource for understanding the molecular basis of pepper resistance to Xcv infection and for improving the disease resistance of pepper cultivars.展开更多
Mango bacterial canker is caused by Xanthomonas campestris pv. mangiferaeindicae. During 2009 and 2013,leaves,twigs and fruits of mango were collected from commercial and experimental mango fields with typical canker ...Mango bacterial canker is caused by Xanthomonas campestris pv. mangiferaeindicae. During 2009 and 2013,leaves,twigs and fruits of mango were collected from commercial and experimental mango fields with typical canker symptoms in Hainan,Guangxi,Guangdong and Szechwan Provinces of China. The causal agent was identified as X. campestris pv. mangiferaeindicae through KC semi-selective medium isolation,pathogenicity tests,and sequencing of the gyrB gene.展开更多
The leaf, bark and seed extracts ofMoringa oleifera were evaluated for their efficacy under field conditions in suppressing Xanthomonas campestris pv. campestris in rape （Brassica napus. L.）. Xanthomonas campestris ...The leaf, bark and seed extracts ofMoringa oleifera were evaluated for their efficacy under field conditions in suppressing Xanthomonas campestris pv. campestris in rape （Brassica napus. L.）. Xanthomonas campestris pv. campestris is an important bacterial pathogen of agricultural importance causing devastating black rot disease of Brassicas. Three extracts concentrations of 60, 100 and 140% were sprayed as foliar applications weekly and the antibacterial activity was evaluated by recording number of totally defoliated plants. The three extracts showed significant effect against the test pathogen （p 〉 0.05）. The antibacterial activity of seed extract demonstrated higher activity against the Xanthomonas campestris pv. campestris as evidenced by lower mean leaf defoliation of 1.59 cm followed by bark （2.58 cm） and lastly leaf extracts （2.96 cm） （p 〈 0.05）. There were no significant differences based on the concentration levels used. Observations revealed that 100% and 140% levels were not significantly different from each other on enhancing growth of the stem diameter. Moringa seed at 60% concentration level can be used to enhance growth of rape. The conclusion is that Moringa seed extracts can be effectively implemented to suppress Xanthomonas campestris pv. campestris pathogen in field grown rape in an integrated disease control program.展开更多
Bacterial proliferation in hosts requires activation of a number of housekeeping pathways, including purine de novo biosynthesis. Although inactivation of purine biosynthesis genes can attenuate virulence, it is uncle...Bacterial proliferation in hosts requires activation of a number of housekeeping pathways, including purine de novo biosynthesis. Although inactivation of purine biosynthesis genes can attenuate virulence, it is unclear which biochemical or virulence factors are associated with the purine biosynthesis pathway in vivo. We report that inactivation of purC, a gene encoding phosphoribosylaminoimidazole-succinocarboxamide synthase, caused complete loss of virulence in Xanthomonas campestris pv. cam- pestris, the causal agent of black rot disease of cruciferous plants. The purC mutant was a purine auxotroph; it could not grow on minimal medium, whereas addition of purine derivatives, such as hypoxanthine or adenine plus guanine, restored growth of the mutant. The purC mutation also significantly enhanced the production of an unknown purine synthesis associated pigment and extracellular polysaccharides by the bacterium. In addition, comparative proteomic analyses of bacteria grown on rich and minimal media revealed that the purC mutation affected the expression levels of diverse proteins involved in purine and pyrimidine synthesis, carbon and energy metabolisms, iron uptake, proteolysis, protein secretion, and signal transduction. These results provided clues to understanding the contributions of purine synthesis to bacterial virulence and interactions with host immune systems.展开更多
建立了一种木薯细菌性萎蔫病菌的环介导恒温扩增快速检测方法,为木薯细菌性萎蔫病的快速检测提供有力的技术支持。针对木薯细菌性萎蔫病菌TAL效应器蛋白质(pthBXam)靶序列的6个位点设计4条特异性引物,并对反应温度和内引物浓度等参数进...建立了一种木薯细菌性萎蔫病菌的环介导恒温扩增快速检测方法,为木薯细菌性萎蔫病的快速检测提供有力的技术支持。针对木薯细菌性萎蔫病菌TAL效应器蛋白质(pthBXam)靶序列的6个位点设计4条特异性引物,并对反应温度和内引物浓度等参数进行了优化,设计的引物与试验中提供的其他黄单胞近缘种都没有扩增反应,表现了较好的特异性。LAMP方法对木薯细菌性萎蔫病菌菌株DNA的检测下限为1pg/μL,比常规PCR灵敏度高100倍。该方法采用SYBR Green I染料法对扩增产物闭管检测,裸眼观察颜色变化判断反应结果,能快速、准确地对田间样品进行检测,没有出现假阳性和假阴性。与其他检测方法相比,LAMP方法检测时间短,效率高,降低了设备投入,易于操作,适合木薯细菌性萎蔫病菌的现场检疫和大规模监测。展开更多
文摘Black rot, caused by Xanthomonas campestris pv. campestris (Xcc) is possibly the most important disease of Brassica worldwide. To compare chromosomal positions of Xcc resistance loci in Brassica oleracea between the present and published studies and to develop marker assisted selection (MAS) to resistance against Xcc race 1, we constructed a B. oleracea map, including pW, pX and BoCL markers that were closely linked to previously reported Xcc resistance QTLs. We also analyzed Xcc resistance QTLs by improving our previously reported map derived from the cross of a susceptible double-haploid line (GC P09) with a resistant double-haploid line (Reiho P01). In the nine linkage groups obtained (C1-C9), the major QTL, XccBo(Reiho)2, was derived from Reiho with a maximum LOD score (7.7) in C8. The QTL (LOD 4.4) located in C9, XccBo(GC)1 was derived from the susceptible GC. The other QTL (LOD 4.4), XccBo(Reiho)1, was found in C5. Based on common markers, it was possible to compare our finding Xcc resistance QTLs with the B. oleraceaXcc loci reported by previous authors;XccBo(Reiho)1 and XccBo(GC)1 may be identical to the Xcc resistance QTLs reported previously or a different member contained in the same resistance gene cluster. Our map includes public SSR markers linked to Xcc resistance genes that will promote pyramiding Xcc resistance genes in B. oleracea. The present study will also contribute to a better understanding of genetic control of Xcc resistance.
基金Supported by the National Natural Science Fotmdation of China （No.30370939）, Natural Science Foundation of Zhejiang Province （No.300054） and Science Research Plan of Zhejiang Province （No.2004C22005）.
文摘A phytotoxin from Xanthomonas campestris pv. retroflexus was isolated using a chromatographer and HPLC, and the components were identified to be a mixture of minor molecular compounds including organic acids and cyclo-（proline-phenylalanine）. The greenhouse cultivation test was used to determine the influence of the isolated fractions on the growth of target weed redroot pigweed （Amaranthus retroflexus L）. The experimental results demonstrated that the cyclo-（Pro-Phe） had the weed inhibit activity obviously on dicotyledonous weed and the mixture with six organic acids showed stronger bioactivity. Further, greenhouse and field test were processed, and the test showed that the use of the toxin appeared to have the potential to be developed further as a bioherbicide system to control weedy grasses.
文摘Cassava bacterial blight (CBB) caused by Xanthomonas axonopodis pv. manihotis has been reported in several African countries since 1970. Knowledge of the virulence and diversity of Xanthomonas axonopodis pv. manihotis strains is important for an integrated control of CBB. The main objective of the present study was to characterize strains of Xanthomonas axonopodis collected from various regions in the DR-Congo. There was variability among strains for shape (form), contour (margin) and elevation. Bacterial cell size for the strains analyzed varied from 24.1 μm × 11.3 μm to 11.4 μm × 4.2 μm. All the Xanthomonas axonopodis pv. manihotis strains but one was motile. Two distinctive groups were identified based on radial growth of their colonies. The first group grows faster (7.8-10.5 mm/d) compared to the second group (4.8-6.9 mm/d). Five strains (Gandajika, Inera/Stat, Kansasa, Mulumba and Musakatshi) were classified as virulent with a damage rating ≤ 1 and four were aggressive (Luputa, M'vuazi, Boketa and Kiyaka) with a damage rating > 1. Significant differences were also observed among strains for disease onset, incidence and plant mortality. The highest incidence (33%) of bacterial blight 21 days after infestation (DAI) resulted from the Boketa strain inoculation and the lowest (0 % disease incidence) from INERA/STAT and Musakatshi strains. There was no clear association between geographic origin of the strains and their aggressiveness.
基金supported by grants of the National Key R&D Program of China (Grants Nos.2016YFE0205500 and 2017YFD0101903)the earmarked fund for China Agriculture Research System (Grant No.CARS-23-G28)+2 种基金the China Postdoctoral Science Foundation (Grant No.2017M620305)Natural Science Foundation of Hubei Province (Grant No.2020CFA010)Youth Fund of Hubei Academy of Agricultural Sciences (Grant No.2021NKYJJ04)。
文摘Bacterial spot(BS)is a severe bacterial disease induced by Xanthomonas campestris pv.vesicatoria(Xcv),a pathogen that causes serious damage to pepper growth and yield.It is therefore important to study the mechanisms of pepper resistance to Xcv and to breed and promote Xcvresistant pepper varieties.However,studies of the responses to Xcv infection in peppers at the protein level are limited.Here,we examined Xcv-induced proteomic changes in leaves of the BS susceptible bell pepper ECW and the resistant bell pepper VI037601 using the isobaric tags for relative and absolute quantitation(iTRAQ)-based protein labeling technology.A total of 6,120 distinct proteins were identified,and there were 1,289 significantly differentially accumulated proteins(DAPs)in ECW and VI037601 leaves after Xcv inoculation.Among these,339(250up-and 89 down-regulated)and 479(300 up-and 179 down-regulated)DAPs were specifically identified in ECW and VI037601,respectively,with 459(364 up-and 95 down-regulated)similarly expressed DAPs being shared by ECW and VI037601.Based on bioinformatics analysis,many defense-associated proteins were identified as up-regulated in ECW and VI037601,especially the proteins involved in plant-pathogen interaction,phenylpropanoid biosynthesis,protein processing in the endoplasmic reticulum,and MAPK signaling pathway-plant.Moreover,we evaluated transcript levels of six differentially expressed genes from the iTRAQ results by q RT-PCR.The analysis revealed transcriptional changes that were consistent with the changes at the protein level.This study will provide a valuable resource for understanding the molecular basis of pepper resistance to Xcv infection and for improving the disease resistance of pepper cultivars.
基金Supported by the Ministry of Science and Technology and the Ministry of Agriculture of China(2014hzs1J007-2)
文摘Mango bacterial canker is caused by Xanthomonas campestris pv. mangiferaeindicae. During 2009 and 2013,leaves,twigs and fruits of mango were collected from commercial and experimental mango fields with typical canker symptoms in Hainan,Guangxi,Guangdong and Szechwan Provinces of China. The causal agent was identified as X. campestris pv. mangiferaeindicae through KC semi-selective medium isolation,pathogenicity tests,and sequencing of the gyrB gene.
文摘The leaf, bark and seed extracts ofMoringa oleifera were evaluated for their efficacy under field conditions in suppressing Xanthomonas campestris pv. campestris in rape （Brassica napus. L.）. Xanthomonas campestris pv. campestris is an important bacterial pathogen of agricultural importance causing devastating black rot disease of Brassicas. Three extracts concentrations of 60, 100 and 140% were sprayed as foliar applications weekly and the antibacterial activity was evaluated by recording number of totally defoliated plants. The three extracts showed significant effect against the test pathogen （p 〉 0.05）. The antibacterial activity of seed extract demonstrated higher activity against the Xanthomonas campestris pv. campestris as evidenced by lower mean leaf defoliation of 1.59 cm followed by bark （2.58 cm） and lastly leaf extracts （2.96 cm） （p 〈 0.05）. There were no significant differences based on the concentration levels used. Observations revealed that 100% and 140% levels were not significantly different from each other on enhancing growth of the stem diameter. Moringa seed at 60% concentration level can be used to enhance growth of rape. The conclusion is that Moringa seed extracts can be effectively implemented to suppress Xanthomonas campestris pv. campestris pathogen in field grown rape in an integrated disease control program.
基金supported by the grants from the National Basic Research Program of the Ministry of Science and Technology of China(No.2011CB100700)the National Science Foundation of China(Nos.31100065 and 31070081)the Basic Research of Frontiers of the Chinese Academy of Sciences(No.KSCX2-EW-J-6)
文摘Bacterial proliferation in hosts requires activation of a number of housekeeping pathways, including purine de novo biosynthesis. Although inactivation of purine biosynthesis genes can attenuate virulence, it is unclear which biochemical or virulence factors are associated with the purine biosynthesis pathway in vivo. We report that inactivation of purC, a gene encoding phosphoribosylaminoimidazole-succinocarboxamide synthase, caused complete loss of virulence in Xanthomonas campestris pv. cam- pestris, the causal agent of black rot disease of cruciferous plants. The purC mutant was a purine auxotroph; it could not grow on minimal medium, whereas addition of purine derivatives, such as hypoxanthine or adenine plus guanine, restored growth of the mutant. The purC mutation also significantly enhanced the production of an unknown purine synthesis associated pigment and extracellular polysaccharides by the bacterium. In addition, comparative proteomic analyses of bacteria grown on rich and minimal media revealed that the purC mutation affected the expression levels of diverse proteins involved in purine and pyrimidine synthesis, carbon and energy metabolisms, iron uptake, proteolysis, protein secretion, and signal transduction. These results provided clues to understanding the contributions of purine synthesis to bacterial virulence and interactions with host immune systems.
文摘建立了一种木薯细菌性萎蔫病菌的环介导恒温扩增快速检测方法,为木薯细菌性萎蔫病的快速检测提供有力的技术支持。针对木薯细菌性萎蔫病菌TAL效应器蛋白质(pthBXam)靶序列的6个位点设计4条特异性引物,并对反应温度和内引物浓度等参数进行了优化,设计的引物与试验中提供的其他黄单胞近缘种都没有扩增反应,表现了较好的特异性。LAMP方法对木薯细菌性萎蔫病菌菌株DNA的检测下限为1pg/μL,比常规PCR灵敏度高100倍。该方法采用SYBR Green I染料法对扩增产物闭管检测,裸眼观察颜色变化判断反应结果,能快速、准确地对田间样品进行检测,没有出现假阳性和假阴性。与其他检测方法相比,LAMP方法检测时间短,效率高,降低了设备投入,易于操作,适合木薯细菌性萎蔫病菌的现场检疫和大规模监测。
