Disease Resistance and Molecular Variations in Irradiation Induced Mutants of Two Pea Cultivars

Abstract

Induced mutation is useful for improving the disease resistance of various crops. Fusarium wilt and powdery mildew are two important diseases which severely influence pea production worldwide. In this study, we first evaluated Fusarium wilt and powdery mildew resistance of mutants derived from two elite vegetable pea cultivars, Shijiadacaiwan 1 (SJ1) and Chengwan 8 (CW8), respectively. Nine SJ1 and five CW8 M3 mutants showed resistant variations in Fusarium wilt, and the same five CW8 mutants in powdery mildew. These resistant variations were confirmed in M4 and M5 mutants as well. Then, we investigated the genetic variations and relationships of mutant lines using simple sequence repeat (SSR) markers. Among the nine effective SSR markers, the genetic diversity index and polymorphism information content (PIC) values were averaged at 0.55 and 0.46, which revealed considerable genetic variations in the mutants. The phylogenetic tree and population structure analyses divided the M3 mutants into two major groups at 0.62 genetic similarity (K = 2), which clearly separated the mutants of the two cultivars and indicated that a great genetic difference existed between the two mutant populations. Further, the two genetic groups were divided into five subgroups at 0.86 genetic similarity (K = 5) and each subgroup associated with resistant phenotypes of the mutants. Finally, the homologous PsMLO1 cDNA of five CW8 mutants that gained resistance to powdery mildew was amplified and cloned. A 129 bp fragment deletion was found in the PsMLO1 gene, which was in accord with er1-2. The findings provide important information on disease resistant and molecular variations of pea mutants, which is useful for pea production, new cultivar breeding, and the identification of resistance genes.

Breeding for Biotic Stress Resistance in Pea

“…Induced mutagenesis has been frequently used in legume breeding and remains a valuable breeding tool [146][147][148]. Large mutant collections can be easily produced through chemical or physical methods.…”

“…However, identification of the desired mutants within these large collections required the availability of a strong selection method. Although tedious, this approach has allowed the identification of mutants with resistance against powdery mildew [148][149][150], fusarium wilt [151], and aphanomyces root rot [152]. More recently, the establishment of targeted-induced local lesion in the genome (TILLING) and deletion-TILLING platforms has facilitated high-throughput identification of mutated sites [153,154].…”

Fine Mapping and Identification of a Fusarium Wilt Resistance Gene FwS1 in Pea

“…The Fusarium wilt resistance pea cultivar Shijiadacaiwan 1 (SJ1) and susceptible line Y4 selected from SJ1 were crossed to construct mapping populations (Deng et al 2022a). The F 1 pea seeds was selfpollinated and conducted to obtain six F 2 populations (SJ1 × Y4 or Y4 × SJ1) comprising a total of 589 individual plants (Table 1) that were used for BSA-seq and the further ne mapping analysis.…”

A Commemorative Issue in Honor of 200th Anniversary of the Birth of Gregor Johann Mendel: The Genius of Genetics

“…In addition to spontaneous mutations used early in genetic research, induced mutations are useful for crop breeding. Deng et al [5] have mutagenized two garden pea varieties susceptible to powdery mildew and Fusarium wilt by irradiation. The progeny were screened for resistance to Fusarium wilt and powdery mildew.…”