Find in Library

Powdery mildew caused by <i>Erysiphe pisi</i> DC. is a major disease affecting pea worldwide. This study aimed to confirm the resistance genes contained in three powdery mildew-resistant Chinese pea landraces (Suoshadabaiwan, Dabaiwandou, and Guiwan 1) and to develop the functional markers of the novel resistance genes. The resistance genes were identified by genetic mapping and <i>PsMLO1</i> gene sequence identification. To confirm the inheritance of powdery mildew resistance in the three Landraces, the susceptible cultivars Bawan 6, Longwan 1, and Chengwan 8 were crossed with Suoshadabaiwan, Dabaiwandou, and Guiwan 1 to produce F₁, F₂, and F_2:3 populations, respectively. All F₁ plants were susceptible to <i>E</i><i>. pisi</i>, and phenotypic segregation patterns in all the F₂ and F_2:3 populations fit the 3:1 (susceptible: resistant) and 1:2:1 (susceptible homozygotes: heterozygotes: resistant homozygotes) ratios, respectively, indicating powdery mildew resistance in the three Landraces were controlled by a single recessive gene, respectively. The analysis of <i>er1</i>-linked markers and genetic mapping in the F₂ populations suggested that the recessive resistance genes in three landraces could be <i>er1</i> alleles. The cDNA sequences of 10 homologous <i>PsMLO1</i> cDNA clones from the contrasting parents were obtained. A known <i>er1</i> allele, <i>er1</i>-4, was identified in Suoshadabaiwan. Two novel <i>er1</i> alleles were identified in Dabaiwandou and Guiwan 1, which were designated as <i>er1</i>-13 and <i>er1</i>-14, respectively. Both novel alleles were characterized with a 1-bp deletion (T) in positions 32 (exon 1) and 277 (exon 3), respectively, which caused a frame-shift mutation to result in premature termination of translation of <i>PsMLO1</i> protein. The co-dominant functional markers specific for <i>er1</i>-13 and <i>er1</i>-14, KASPar-<i>er1</i>-13, and KASPar-<i>er1</i>-14 were developed and effectively validated in populations and pea germplasms. Here, two novel <i>er1</i> alleles were characterized and their functional markers were validated. These results provide powerful tools for marker-assisted selection in pea breeding.