Fine Mapping of a Resistance Gene RpsHN that Controls Phytophthora sojae Using Recombinant Inbred Lines and Secondary Populations

Abstract

Phytophthora root rot (PRR), caused by Phytophthora sojae, has negative effects on soybean yield in China and can be controlled by identifying germplasm resources with resistance genes. In this study, the resistance locus RpsHN in the soybean line Meng8206 was mapped using two mapping populations. Initial mapping was realized using two recombinant inbred line (RIL) populations and included 103 F6:8 RILs derived from a cross of Meng8206 × Linhedafenqing, including 2600 bin markers, and 130 F6:8 RILs derived from a cross of Meng8206 × Zhengyang148, including 2267 bin markers. Subsequently, a 159 F2:3 secondary population derived from a cross of Meng8206 × Linmeng6-46, were used to fine map this locus using SSR markers. Finally, the resistance locus from Meng8206 was fine mapped to a 278.7 kb genomic region flanked by SSR markers SSRSOYN-25 and SSRSOYN-44 at a genetic distance of 1.6 and 1.0 cM on chromosome 3 (Chr. 03). Real-time RT-PCR analysis of the possible candidate genes showed that three genes (Glyma.03g04260, Glyma.03g04300, and Glyma.03g04340) are likely involved in PRR resistance. These results will serve as a basis for cloning, transferring of resistant genes and breeding of P. sojae-resistant soybean cultivars through marker-assisted selection.

Fine mapping of a Phytophthora-resistance locus RpsGZ in soybean using genotyping-by-sequencing

“…Soybean is one of the most important crops in the world. There are a large number of soybean accessions in China, among which many PRR-resistant cultivars/ lines were identified in a previous study [10,13,14,[51][52][53][54][55]. In the present study, the Guizao1 cultivar was PRR resistant to P. sojae PNJ4 and PNJ1, thus differing from the other soybean cultivars tested (Table 1).…”

“…Previous studies have identified 17 known Rps genes (alleles) and mapped them to chromosome 3 before RpsGZ, including five alleles of Rps1 (Rps1a, 1b, 1c, 1d, 1 k) [23,24,38,57,58], Rps7 [23], Rps9 [29], RpsYu25 [25], an Rps gene in Waseshiroge [26], RpsYD29 [27], an Rps gene in E00003 soybean within the Rps1 k interval [30], RpsHC18 [10], RpsQ [13], RpsHN [14], RpsX [9], RpsWY [31], and RpsUN1 [28]. Nevertheless, the positional relationships of these Rps genes had not been confirmed, and some of the mapping intervals for these Rps genes overlapped.…”

“…RpsUN1 was localized to the region between 4,020,587 and 4,171,402 bp, flanked by two SSR markers, BARCSOYSSR_03_ 0233 and BARCSOYSSR_03_0246, based on the Glyma 2.0 soybean gene annotation database of the Williams 82 genome sequence [28]. Among the regions of four other known Rps genes according to the Glyma1.0 annotations, the Waseshiroge Rps gene was located between Satt009 and T003044871 and may reside in the [14]. RpsYD29 was flanked by the markers SattWM82-50 and Satt1 k4b, which were located at nucleotide positions 3,857,715 and 4,062,474 bp [27].…”

“…RpsQ, RpsX and an unnamed Rps gene in Wascshiroge and E00003 soybean were mapped to chromosome 3 [7,9,10,13,14,[22][23][24][25][26][27][28][29][30][31]. Rps3 (including three alleles, Rps3a, Rps3b and Rps3c) and RpsSN10 were mapped to chromosome 13, which is linked with Rps8 [6,22,32,33].…”

Genome-wide association analyses of quantitative disease resistance in diverse sets of soybean [Glycine max (L.) Merr.] plant introductions

“…Genetic resistance is considered the most effective strategy for preventing or reducing the impact of Phytophthora diseases [4,7].Soybean-breeding programs have relied on resistance conferred by single, dominantly inherited Resistance to Phytophthora sojae (Rps)-genes. More than 30 Rps-genes/alleles have been mapped (S1 Table) [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. The effectiveness of Rps-mediated resistance is limited as these genes only confer immunity towards specific races of P. sojae.…”