Discovery of a seventh Rpp soybean rust resistance locus in soybean accession PI 605823

Abstract

A novel Rpp gene from PI 605823 for resistance to Phakopsora pachyrhizi was mapped on chromosome 19. Soybean rust, caused by the obligate biotrophic fungal pathogen Phakopsora pachyrhizi Syd. & P. Syd, is a disease threat to soybean production in regions of the world with mild winters. Host plant resistance conditioned by resistance to P. pachyrhizi (Rpp) genes has been found in numerous soybean accessions, and at least 10 Rpp genes or alleles have been mapped to six genetic loci. Identifying additional disease-resistance genes will facilitate development of soybean cultivars with durable resistance. PI 605823, a plant introduction from Vietnam, was previously identified as resistant to US populations of P. pachyrhizi in greenhouse and field trials. In this study, bulked segregant analysis using an F population derived from 'Williams 82' × PI 605823 identified a genomic region associated with resistance to P. pachyrhizi isolate GA12, which had been collected in the US State of Georgia in 2012. To further map the resistance locus, linkage mapping was carried out using single-nucleotide polymorphism markers and phenotypic data from greenhouse assays with an F population derived from Williams 82 × PI 605823 and an F population derived from '5601T' × PI 605823. A novel resistance gene, Rpp7, was mapped to a 154-kb interval (Gm19: 39,462,291-39,616,643 Glyma.Wm82.a2) on chromosome 19 that is different from the genomic locations of any previously reported Rpp genes. This new gene could be incorporated into elite breeding lines to help provide more durable resistance to soybean rust.

Pyramiding three rust‐resistance genes confers a high level of resistance in soybean (Glycine max)

“…Utilization of the host's genetic resistance to ASR offers an environmentally‐friendly and cost‐effective alternative to fungicide use that can allow long‐term management of the ASR pathogen (Ribeiro et al, ). Eight Rpp loci for resistance to P. pachyrhizi have been identified to date ( Rpp1–Rpp7 and Rpp1‐b ) and mapped at different loci (Chakraborty et al, ; Childs et al, ; Garcia et al, ; Hossain et al, ; Hyten et al, , ; Li, Smith, Ray, & Frederick, ; Silva et al, ). These genes are now available for marker assisted breeding but are only effective against specific P. pachyrhizi races and so rarely offer durable resistance to the highly variable ASR pathogen (Oliveira, Godoy, & Martins, ), which limits their use for developing ASR‐resistant soybean, particularly in areas where the pathogen is highly virulent (Akamatsu et al, , ; García‐Rodríguez, Morishita, Kato, & Yamanaka, ; Stewart, Rodrígue, & Yamanaka, ; Yamanaka et al, , ).…”

Research Article Identification of SSR markers linked to partial resistance to soybean rust in Brazil from crosses using the resistant genotype IAC 100

“…Linkage groups C2 (chromosome 6), G (18), J (16), N (3) and L (19) are known in the literature because they contain vertical genes related to resistance to soybean rust (Garcia et al, 2008;Silva et al, 2008;Hyten et al, 2009;Li et al, 2012;Childs et al, 2018). QTLs were identified in the C2, G and N groups.…”

Spray volume deposits and fungicide efficacy on soybean rust (Phakopsora pachyrhizi)

“…This is not only because the disease spreads rapidly, but also because it can cause significant yield reductions where management practices are poor (Prado et al, 2015). Despite many studies on the development of soybean cultivars resistant to P. pachyrhizi (Langenbach et al, 2016;Vuong et al, 2016;Childs et al 2018), control has been difficult due to the variability and dynamic plasticity of the rust population, varying in virulence and genetic composition (Murithi et al, 2016). One of the most effective management strategies to suppress SBR severity and to reduce yield loss is the application of sequential fungicides (Scherm et al, 2009;Costa et al, 2015;Prado et al, 2015).…”