In China,Xinjiang is a relatively independent epidemic region of wheat stripe rust,caused by Puccinia striiformis f.sp.tritici,due to great population genetic divergence of Xinjiang with other inland epidemic regions....In China,Xinjiang is a relatively independent epidemic region of wheat stripe rust,caused by Puccinia striiformis f.sp.tritici,due to great population genetic divergence of Xinjiang with other inland epidemic regions.In this region,race evolution was usually slower than inland populations.However,many new races have recently been found,and therefore,it is necessary for more understanding of the virulence evolution of the Xinjiang population.So,in this study,a 65 sexual progenies,derived from a Xinjiang single-urediospore isolate BGTB-1 of P.striiformis f.sp.tritici by selfing on alternate host barberry(Berberis aggregata).It was phenotyped on the 25 single Yr lines,and genotyped by 19 kompetitive allele-specific PCRsingle nucleotide polymorphism(KASP-SNP) markers.As a result,the 65 progenies were identified as 56 various virulence patterns(VPs),and neither of which was identical to the parental isolate,showed 100% virulence variation.Compared with the parental isolate,of all progenies,39(60.0%) had increased virulence,and 18(27.7%) had decreased virulence.All progenies exhibited avirulence to Yr10,Yr15,Yr32,and YrTr1 loci,and avirulence and virulence segregation at the remaining 21 Yr resistance loci.The results showed avirulence to Yr5,Yr7,and Yr76(A:V≈3:1) loci is controlled by a single dominant gene,and that to Yr6,Yr25,and Yr44(A:V≈1:3) loci by a single recessive gene.However,avirulence to the remaining 15 resistant loci including Yr1,Yr2,Yr3,Yr4,Yr8,Yr9,Yr17,Yr26(=Yr24),Yr28,Yr29,Yr43,YrSP,Yr27,YrA,and YrExp2,with various avirulence and virulence segregation ratios,is controlled by two genes with different gene effects,indicating complex genetic traits of the parental isolate.Totally,65 dissimilar genotypes detected among progenies using overall molecular markers,by which a linkage map was constructed,with a genetic distance of 441.0 cM.Interestingly,although the parental isolate was avirulent to Yr5,but 17 progenies showed virulence,showing the change of pathogenicity from avirulence to virulence at this resistance locus.It was for the first time to report that progenies with virulence to Yr5 produced sexually from avirulent parental isolate at this resistance locus.To our knowledge,this study offers an insight into inheritance,sexual reproduction and virulence variation of P.striiformis f.sp.tritici in Xinjiang,facilitating us to understand evolution of the rust pathogen in this region and accounting for Xinjiang population distinguished form other inland populations.Additionally,it is necessary to further confirm the roles of sexual reproduction in the emergence of new races and affecting population genetic diversity of P.striiformis f.sp.tritici under natural conditions in Xinjiang.展开更多
为研究真空等离子喷涂Si/Yb_(2)Si_(2)O_(7)/Yb_(2)SiO_(5)环境障涂层试样在涂层受压、涂层受拉时的室温弯曲强度及失效原因,采用超景深三维显微镜、SEM(Scanning Electron Microscope)等方法对喷涂后的试样进行了表征,并测量了涂层孔隙...为研究真空等离子喷涂Si/Yb_(2)Si_(2)O_(7)/Yb_(2)SiO_(5)环境障涂层试样在涂层受压、涂层受拉时的室温弯曲强度及失效原因,采用超景深三维显微镜、SEM(Scanning Electron Microscope)等方法对喷涂后的试样进行了表征,并测量了涂层孔隙率;采用拉伸法测试了涂层的结合强度,并采用三点弯曲试验测试了裸材、涂层受压和涂层受拉时的室温弯曲强度。结果表明:Si/Yb_(2)Si_(2)O_(7)/Yb_(2)SiO_(5)涂层与SiC_(f)/SiC复合材料的结合强度为10.13 MPa,拉伸断裂主要在复材表层发生。计算涂层厚度时,涂层受压样的弯曲强度(503.21 MPa)与裸材(506.79 MPa)基本一致;不计算涂层厚度时,涂层受拉样的弯曲强度(499.77 MPa)与裸材一致;EBC涂层整体具有一定的压缩强度,其整体抗拉强度比复材自身抗拉强度小很多。压涂层时,在载荷增加至接近最大载荷时,复材层间发生破坏,并逐步失效,随后涂层发生飞崩,载荷迅速下降,试验停止;拉涂层时,在载荷很小时(约64 N)涂层就被拉开,随着载荷增加,直至接近最大载荷时,层间发生破坏并逐步失效。弯曲试验时复材的主要失效模式是SiC纤维断裂、复材的SiC基体开裂和复材层间撕裂,复材受拉面产生复材厚度方向的纵向裂纹;复材表层沉积的SiC膜层失效模式主要是开裂和剥落;EBC涂层在受压时的主要失效模式是整体飞崩和开裂,在受拉时,涂层在最大应力处断裂为2部分。本研究对含EBC涂层的SiC_(f)/SiC复材的最大弯曲载荷设计具有参考意义.展开更多
基金financially supported by Xinjiang Major Science and Technology Projects,China (2023A02009)。
文摘In China,Xinjiang is a relatively independent epidemic region of wheat stripe rust,caused by Puccinia striiformis f.sp.tritici,due to great population genetic divergence of Xinjiang with other inland epidemic regions.In this region,race evolution was usually slower than inland populations.However,many new races have recently been found,and therefore,it is necessary for more understanding of the virulence evolution of the Xinjiang population.So,in this study,a 65 sexual progenies,derived from a Xinjiang single-urediospore isolate BGTB-1 of P.striiformis f.sp.tritici by selfing on alternate host barberry(Berberis aggregata).It was phenotyped on the 25 single Yr lines,and genotyped by 19 kompetitive allele-specific PCRsingle nucleotide polymorphism(KASP-SNP) markers.As a result,the 65 progenies were identified as 56 various virulence patterns(VPs),and neither of which was identical to the parental isolate,showed 100% virulence variation.Compared with the parental isolate,of all progenies,39(60.0%) had increased virulence,and 18(27.7%) had decreased virulence.All progenies exhibited avirulence to Yr10,Yr15,Yr32,and YrTr1 loci,and avirulence and virulence segregation at the remaining 21 Yr resistance loci.The results showed avirulence to Yr5,Yr7,and Yr76(A:V≈3:1) loci is controlled by a single dominant gene,and that to Yr6,Yr25,and Yr44(A:V≈1:3) loci by a single recessive gene.However,avirulence to the remaining 15 resistant loci including Yr1,Yr2,Yr3,Yr4,Yr8,Yr9,Yr17,Yr26(=Yr24),Yr28,Yr29,Yr43,YrSP,Yr27,YrA,and YrExp2,with various avirulence and virulence segregation ratios,is controlled by two genes with different gene effects,indicating complex genetic traits of the parental isolate.Totally,65 dissimilar genotypes detected among progenies using overall molecular markers,by which a linkage map was constructed,with a genetic distance of 441.0 cM.Interestingly,although the parental isolate was avirulent to Yr5,but 17 progenies showed virulence,showing the change of pathogenicity from avirulence to virulence at this resistance locus.It was for the first time to report that progenies with virulence to Yr5 produced sexually from avirulent parental isolate at this resistance locus.To our knowledge,this study offers an insight into inheritance,sexual reproduction and virulence variation of P.striiformis f.sp.tritici in Xinjiang,facilitating us to understand evolution of the rust pathogen in this region and accounting for Xinjiang population distinguished form other inland populations.Additionally,it is necessary to further confirm the roles of sexual reproduction in the emergence of new races and affecting population genetic diversity of P.striiformis f.sp.tritici under natural conditions in Xinjiang.
