Jiang Chengzhi, Luo Yujie, Qi Yile, Li Li, Jiang Tingting, Yang Ennian, Li Guangrong, Yang Zujun
School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, China.
Crop Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, China.
Theor Appl Genet. 2025 Aug 22;138(9):226. doi: 10.1007/s00122-025-05018-3.
Stripe rust (Puccinia striiformis f. sp. tritici) is a globally devastating foliar disease affecting common wheat. The development of new wheat varieties with novel and durable stripe rust resistance through wide hybridization represents a sustainable and cost-effective strategy for controlling the disease. Thinopyrum ponticum (Podp.) Barkworth & D.R. Dewey, a polyploid species in the tertiary genetic pool of wheat, harbors multiple disease resistance genes, and has been widely utilized for wheat improvement. We previously identified a wheat-Th. ponticum 6J (6B) substitution line X005 with novel stripe rust resistance, which was derived from the wheat-Th. ponticum partial amphiploid Xiaoyan7430. In the present study, the chromosome compositions of Xiaoyan7430 and X005 were precisely characterized using non-denaturing - fluorescence in situ hybridization (ND-FISH) and Oligo-FISH painting. Notably, chromosome 6J in X005 displayed distinctly different ND-FISH patterns compared to other reported Th. ponticum-derived 6Ae chromosomes introduced into various wheat backgrounds. To physically localize the 6J-derived stripe rust resistance gene from X005, we isolated a set of wheat-6J deletion and translocation lines after extensive screening of the progenies of crosses between X005 and susceptible wheat cultivars. Using 75 molecular markers, we established a cytological bin map for chromosome 6J of X005. Resistance evaluation combined with molecular mapping revealed that the critical resistance locus resides in bin 6JS-2 (FL 0.53-0.67) on the 6J short arm, corresponding to the 74.51-135.61 Mb genome region of Th. elongatum chromosome 6E. This locus confers stripe rust resistance at both the seedling and adult-plant stages. Translocation T6JS·6BL had enhanced Yr resistance and increased tiller numbers without any obvious negative effect on agronomic traits. Thus, the newly developed wheat-Th. ponticum 6J translocation lines represent novel germplasm resources for the breeding of disease-resistant wheat cultivars.
条锈病（条形柄锈菌小麦专化型）是一种影响普通小麦的全球性毁灭性叶部病害。通过远缘杂交培育具有新颖且持久条锈病抗性的新型小麦品种，是控制该病害的一种可持续且经济高效的策略。长穗偃麦草（Podp.）Barkworth & D.R. Dewey是小麦三级基因库中的一个多倍体物种，含有多个抗病基因，已被广泛用于小麦改良。我们之前鉴定出一个具有新颖条锈病抗性的小麦-长穗偃麦草6J（6B）代换系X005，它源自小麦-长穗偃麦草部分双二倍体小偃7430。在本研究中，利用非变性荧光原位杂交（ND-FISH）和寡核苷酸荧光原位杂交图谱技术精确鉴定了小偃7430和X005的染色体组成。值得注意的是，与其他报道的导入不同小麦背景的源自长穗偃麦草的6Ae染色体相比，X005中的6J染色体呈现出明显不同的ND-FISH模式。为了从物理位置上定位X005中源自6J的条锈病抗性基因，我们在广泛筛选X005与感病小麦品种杂交后代后，分离出了一组小麦-6J缺失系和易位系。利用75个分子标记，我们构建了X005的6J染色体细胞学图谱。抗性评估与分子定位相结合表明，关键抗性位点位于6J短臂的6JS-2（FL 0.53-0.67）区间，对应于长穗偃麦草6E染色体的74.51-135.61 Mb基因组区域。该位点在幼苗期和成年植株期均赋予条锈病抗性。易位系T6JS·6BL增强了对条锈病的抗性，增加了分蘖数，且对农艺性状没有任何明显的负面影响。因此，新培育的小麦-长穗偃麦草6J易位系代表了抗病小麦品种育种的新型种质资源。
