Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
ICAR-Directorate of Groundnut Research, Junagadh, 362001, India.
Theor Appl Genet. 2020 Sep;133(9):2685-2694. doi: 10.1007/s00122-020-03625-w. Epub 2020 Jun 7.
A novel leaf rust resistance gene, LrM, introgressed from Aegilops markgrafii and mapped on chromosome 2AS using SSR- and SNP-based PCR markers will aid in broadening the genetic base of rust resistance in wheat. A new leaf rust resistance gene tentatively named LrM was introgressed from the diploid non-progenitor species Ae. markgrafii (2n = 2x = 14, genome CC) into common wheat using the nulli-5B mechanism. The introgression line ER9-700 showed a high degree of resistance against a wide spectrum of Puccinia triticina pathotypes. Genetic analysis was performed using the F, F, F and BCF generations derived from the cross ER9-700/Agra Local. The results showed a single dominant gene for leaf rust resistance. The resistance gene LrM was mapped on chromosome arm 2AS using SSR- and SNP-based PCR markers. Preliminary mapping with SSR markers in the F population from the cross ER9-700/Agra Local identified two SSR markers flanking the LrM. SNPs were identified in the genomic region flanked by SSR markers, and SNP-based PCR markers were developed to construct the final map. Three SNP-based PCR markers co-segregated and mapped closest to the resistance gene at a distance of 2 cM. The gene LrM was distinguished from all the other genes designated and mapped on chromosome arm 2AS by molecular markers and rust reaction. All five markers used in the mapping amplified identical alleles in the donor Ae. markgrafii accession and introgression line ER9-700. The chromosomal location and rust reaction suggest that LrM is a novel leaf rust resistance gene that may be useful in broadening the genetic base of leaf rust resistance in wheat.
一个从节节麦中新导入的、含有叶锈病抗性基因 LrM 的染色体 2AS，利用 SSR 和 SNP 为基础的 PCR 标记进行定位，将有助于拓宽小麦锈病抗性的遗传基础。通过利用单体 5B 机制，将一个从二倍体非祖源物种节节麦（2n=2x=14，CC 基因组）中导入普通小麦的新叶锈病抗性基因暂定命名为 LrM。导入系 ER9-700 对广泛的小麦叶锈菌生理小种表现出高度抗性。利用 ER9-700/Agra Local 杂交的 F、F、F 和 BCF 世代进行遗传分析。结果表明，该基因对叶锈病的抗性表现为单个显性基因。利用基于 SSR 和 SNP 的 PCR 标记将 LrM 基因定位到 2AS 染色体臂上。通过 ER9-700/Agra Local 杂交的 F 群体中的 SSR 标记进行初步定位，确定了两个侧翼 LrM 的 SSR 标记。在 SSR 标记侧翼的基因组区域中鉴定到 SNP，并开发了 SNP 为基础的 PCR 标记来构建最终图谱。三个 SNP 为基础的 PCR 标记紧密连锁并共分离，与抗性基因的距离为 2cM。LrM 基因通过分子标记和锈病反应与位于 2AS 染色体臂上的所有其他基因标记和锈病反应区分开来。在作图中使用的所有 5 个标记在供体节节麦和导入系 ER9-700 中扩增出相同的等位基因。该基因的染色体定位和锈病反应表明，LrM 是一个新的叶锈病抗性基因，可能有助于拓宽小麦叶锈病抗性的遗传基础。
