Abstract
Powdery mildew caused by Erysiphe pisi DC. severely affects pea crops worldwide. The use of resistant cultivars containing the er1 gene is the most effective way to control this disease. The objectives of this study were to reveal er1 alleles contained in 55 E. pisi-resistant pea germplasms and to develop the functional markers of novel alleles. Sequences of 10 homologous PsMLO1 cDNA clones from each germplasm accession were used to determine their er1 alleles. The frame shift mutations and various alternative splicing patterns were observed during transcription of the er1 gene. Two novel er1 alleles, er1-8 and er1-9, were discovered in the germplasm accessions G0004839 and G0004400, respectively, and four known er1 alleles were identified in 53 other accessions. One mutation in G0004839 was characterized by a 3-bp (GTG) deletion of the wild-type PsMLO1 cDNA, resulting in a missing valine at position 447 of the PsMLO1 protein sequence. Another mutation in G0004400 was caused by a 1-bp (T) deletion of the wild-type PsMLO1 cDNA sequence, resulting in a serine to leucine change of the PsMLO1 protein sequence. The er1-8 and er1-9 alleles were verified using resistance inheritance analysis and genetic mapping with respectively derived F2 and F2:3 populations. Finally, co-dominant functional markers specific to er1-8 and er1-9 were developed and validated in populations and pea germplasms. These results improve our understanding of E. pisi resistance in pea germplasms worldwide and provide powerful tools for marker-assisted selection in pea breeding.
Highlights
Pea (Pisum sativum L.) is a widely distributed legume crop, which frequently suffers from various stresses, including abiotic and biotic factors in the season of growth [1,2]
Fifty-five E. pisi-immune or -resistant pea germplasm accessions from 13 countries were re-evaluated for their resistance to the E. pisi isolate EPYN
Our results showed that none of the other 169 pea germplasm accessions carried the er1-8 or er1-9 alleles
Summary
Pea (Pisum sativum L.) is a widely distributed legume crop, which frequently suffers from various stresses, including abiotic and biotic factors in the season of growth [1,2]. Powdery mildew, induced by Erysiphe pisi DC., severely reduces the yield and quality of pea crops worldwide [3,4,5]. Severe E. pisi infections of peas can lead to yield losses of up to 80% in regions which are suitable for disease development [5,6]. Since 2005, two other Erysiphe species, Erysiphe trifolii and Erysiphe baeumleri, have been reported to infect peas and induce the same powdery mildew symptoms as E. pisi in some regions [8,9,10]. Previous studies of pea powdery mildew have primarily focused on breeding peas resistant to E. pisi. Er3, which was isolated from wild pea (Pisum fulvum), was initially mapped on an uncertain pea LG, but it was more recently assigned to pea LG IV [29]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
