Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici(Pst), is an airborne disease. In China, it frequently develops initially in central Shaanxi and southwestern Gansu, and from there, inoculum spreads to ...Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici(Pst), is an airborne disease. In China, it frequently develops initially in central Shaanxi and southwestern Gansu, and from there, inoculum spreads to the eastern wheat production regions. Field investigations have suggested that Pst could spread from the west to the east within central Shaanxi andthat Gansu could serve as the inoculum source for central Shaanxi, but there is no direct evidence for this hypothetical dispersal route. In the current study, 321 Pst isolates collected from central Shaanxi and Gansu in the 2019–2020 and2020–2021 winter wheat cropping seasons were genotyped using 23 pairs of KASP-SNP markers. The dispersion among subpopulations was analyzed using several approaches, and overall, the populations were found to exhibit high levels of genetic diversity. There was little genetic divergence(0.05>FST>0) within central Shaanxi. However, significant gene flow(Nm>4) driven by wind-oriented dispersal from west(Baoji) to east(Weinan) occurred. There was also gene flow among the 4 Gansu subpopulations of Tianshui, Longnan, Pingliang, and Qingyang. Migration of the pathogen occurred between central Shaanxi and Gansu. Migration from Gansu to central Shaanxi was major compared with that from central Shaanxi to Gansu that was minor. Genetic variation occurred among isolates, instead of among subpopulations and within isolates. Linkage disequilibrium revealed that there was strong genetic recombination in the subpopulations from Gansu and central Shaanxi. Therefore, the present study provides molecular evidence that Pst spread from west to east in central Shaanxi and showed that Gansu(especially Longnan and Tianshui) was one of the major origins of the pathogen inoculum of wheat stripe rust in central Shaanxi. The results revealed the west-to-east transmission route of wheat stripe rust in central Shaanxi, being used to guide integrated management of the disease.展开更多
Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici （Pst）, is a devastating disease that can cause severe yield losses. Identification and utilization of stripe rust resistance genes are essential for e...Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici （Pst）, is a devastating disease that can cause severe yield losses. Identification and utilization of stripe rust resistance genes are essential for effective breeding against the disease. Wild emmer accession TZ-2, originally collected from Mount Hermon, Israel, confers near-immunity resistance against several prevailing Pst races in China. A set of 200 F6：7 recombinant inbred lines （RILs） derived from a cross between susceptible durum wheat cultivar Langdon and TZ-2 was used for stripe rust evaluation. Genetic analysis indicated that the stripe rust resistance of TZ-2 to Pst race CYR34 was controlled by a single dominant gene, temporarily designated YrTZ2. Through bulked segregant analysis （BSA） with SSR markers, YrTZ2 was located on chromosome arm 1BS flanked by Xwmc230 and Xgwm413 with genetic distance of 0.8 cM （distal） and 0.3 cM （proximal）, respectively. By applying wheat 90K iSelect SNP genotyping assay, 11 polymorphic loci （consisting of 250 SNP markers） closely linked to YrTZ2 were identified. YrTZ2 was further delimited into a 0.8-cM genetic interval between SNP marker IWB19368 and SSR marker Xgwm413, and cosegregated with SNP marker IWB28744 （co-segregated with 28 SNP）. Comparative genomics analyses revealed high level of collinearity between the YrTZ2 genomic region and the orthologous region of Aegilops tauschii 1DS. The genomic region between loci IWB19368 and IWB31649 harboring YrTZ2 is orthologous to a 24.5-Mb genomic region between AT1D0112 and AT1D0150, spanning 15 contigs on chromosome 1DS. The genetic and comparative maps of YrTZ2 rovide a framework for map-based cloning and marker-assisted selection of YrTZ2.展开更多
Mitogen-activated protein kinase(MAPK)cascades play a fundamental role in plant immunity by transducing external signals inside plant cells.Here,we defined a wheat MAPK cascade,composed of the mitogen-activated protei...Mitogen-activated protein kinase(MAPK)cascades play a fundamental role in plant immunity by transducing external signals inside plant cells.Here,we defined a wheat MAPK cascade,composed of the mitogen-activated protein kinase kinase(MAPKK)TaMKK2 and its downstream MAPK TaMAPK6,which phosphorylates the core immune regulator TaSGT1(suppressor of G2 allele of Skp1),resulting in enhanced nuclear entry of TaSGT1,thereby conferring resistance against the devastating wheat pathogen Puccinia striiformis f.sp.tritici(Pst).Hence,we identified a TaMKK2-TaMAPK6-TaSGT1 signaling cascade that contributes to wheat stripe rust resistance.During infection,Pst secrets a haustorium-associated secreted protein 215(HASP215),that targets TaMKK2 and interferes with the interaction of TaMKK2 with TaMAPK6 to suppress TaMAPK6 phosphorylation and activation,thereby leading to reduced capacity of TaMAPK6 to phosphorylate TaSGT1.Consequently,inhibition of TaMAPK6-mediated TaSGT1 phosphorylation resulted in decreased nuclear translocation of TaSGT1 and suppressed plant immunity.Our work elucidates the positive function of TaMKK2-TaMAPK6 cascade in wheat immunity by regulating the immune component TaSGT1,and its regulation by the rust effector HASP215,providing new insights into the MAPK cascade on crop immunity and the pathogenicity mechanism of obligate biotrophic fungus.展开更多
基金supported by the National Key R&D Program of China (2021YFD1401000)the National Natural Science Foundation of China (32072358 and 32272507)the Natural Science Basic Research Plan in Shaanxi Province, China (2020JZ-15)。
文摘Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici(Pst), is an airborne disease. In China, it frequently develops initially in central Shaanxi and southwestern Gansu, and from there, inoculum spreads to the eastern wheat production regions. Field investigations have suggested that Pst could spread from the west to the east within central Shaanxi andthat Gansu could serve as the inoculum source for central Shaanxi, but there is no direct evidence for this hypothetical dispersal route. In the current study, 321 Pst isolates collected from central Shaanxi and Gansu in the 2019–2020 and2020–2021 winter wheat cropping seasons were genotyped using 23 pairs of KASP-SNP markers. The dispersion among subpopulations was analyzed using several approaches, and overall, the populations were found to exhibit high levels of genetic diversity. There was little genetic divergence(0.05>FST>0) within central Shaanxi. However, significant gene flow(Nm>4) driven by wind-oriented dispersal from west(Baoji) to east(Weinan) occurred. There was also gene flow among the 4 Gansu subpopulations of Tianshui, Longnan, Pingliang, and Qingyang. Migration of the pathogen occurred between central Shaanxi and Gansu. Migration from Gansu to central Shaanxi was major compared with that from central Shaanxi to Gansu that was minor. Genetic variation occurred among isolates, instead of among subpopulations and within isolates. Linkage disequilibrium revealed that there was strong genetic recombination in the subpopulations from Gansu and central Shaanxi. Therefore, the present study provides molecular evidence that Pst spread from west to east in central Shaanxi and showed that Gansu(especially Longnan and Tianshui) was one of the major origins of the pathogen inoculum of wheat stripe rust in central Shaanxi. The results revealed the west-to-east transmission route of wheat stripe rust in central Shaanxi, being used to guide integrated management of the disease.
基金financially supported by the Science and Technology Service Network Initiative of Chinese Academy of Sciences(KFJ-STS-ZDTP-024)
文摘Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici （Pst）, is a devastating disease that can cause severe yield losses. Identification and utilization of stripe rust resistance genes are essential for effective breeding against the disease. Wild emmer accession TZ-2, originally collected from Mount Hermon, Israel, confers near-immunity resistance against several prevailing Pst races in China. A set of 200 F6：7 recombinant inbred lines （RILs） derived from a cross between susceptible durum wheat cultivar Langdon and TZ-2 was used for stripe rust evaluation. Genetic analysis indicated that the stripe rust resistance of TZ-2 to Pst race CYR34 was controlled by a single dominant gene, temporarily designated YrTZ2. Through bulked segregant analysis （BSA） with SSR markers, YrTZ2 was located on chromosome arm 1BS flanked by Xwmc230 and Xgwm413 with genetic distance of 0.8 cM （distal） and 0.3 cM （proximal）, respectively. By applying wheat 90K iSelect SNP genotyping assay, 11 polymorphic loci （consisting of 250 SNP markers） closely linked to YrTZ2 were identified. YrTZ2 was further delimited into a 0.8-cM genetic interval between SNP marker IWB19368 and SSR marker Xgwm413, and cosegregated with SNP marker IWB28744 （co-segregated with 28 SNP）. Comparative genomics analyses revealed high level of collinearity between the YrTZ2 genomic region and the orthologous region of Aegilops tauschii 1DS. The genomic region between loci IWB19368 and IWB31649 harboring YrTZ2 is orthologous to a 24.5-Mb genomic region between AT1D0112 and AT1D0150, spanning 15 contigs on chromosome 1DS. The genetic and comparative maps of YrTZ2 rovide a framework for map-based cloning and marker-assisted selection of YrTZ2.
基金supported by the National Natural Science Foundation of China(32225041,32272511)Biological Breeding-Major Projects(2023ZD04070)+3 种基金Science Foundation for Distinguished Young Scholars of Shaanxi Province(2024JC-JCQN-22)Central Guiding Local Science and Technology Development Fund of Shaanxi Province(2024ZYJCYJ-02-43)the China Agricultural Research System(CARS-3)Cyrus Tang Foundation.
文摘Mitogen-activated protein kinase(MAPK)cascades play a fundamental role in plant immunity by transducing external signals inside plant cells.Here,we defined a wheat MAPK cascade,composed of the mitogen-activated protein kinase kinase(MAPKK)TaMKK2 and its downstream MAPK TaMAPK6,which phosphorylates the core immune regulator TaSGT1(suppressor of G2 allele of Skp1),resulting in enhanced nuclear entry of TaSGT1,thereby conferring resistance against the devastating wheat pathogen Puccinia striiformis f.sp.tritici(Pst).Hence,we identified a TaMKK2-TaMAPK6-TaSGT1 signaling cascade that contributes to wheat stripe rust resistance.During infection,Pst secrets a haustorium-associated secreted protein 215(HASP215),that targets TaMKK2 and interferes with the interaction of TaMKK2 with TaMAPK6 to suppress TaMAPK6 phosphorylation and activation,thereby leading to reduced capacity of TaMAPK6 to phosphorylate TaSGT1.Consequently,inhibition of TaMAPK6-mediated TaSGT1 phosphorylation resulted in decreased nuclear translocation of TaSGT1 and suppressed plant immunity.Our work elucidates the positive function of TaMKK2-TaMAPK6 cascade in wheat immunity by regulating the immune component TaSGT1,and its regulation by the rust effector HASP215,providing new insights into the MAPK cascade on crop immunity and the pathogenicity mechanism of obligate biotrophic fungus.
