<b>Microsatellite molecular marker-assisted gene pyramiding for resistance to Asian soybean rust (ASR)

Abstract

The present study aimed at pyramiding ASR-resistance genes through microsatellite (SSR) marker-assisted selection (MAS) and demonstrating the pyramiding steps. To obtain the first generation of gene pyramiding, crosses were made between introduced plants (PI's), which have the genes Rpp1, Rpp2, Rpp3, Rpp4, and Rpp5. F 1 plants from the initial crosses were intercrossed to obtain plants with the four resistance genes (second pyramiding generation). Plants selected from this second generation were again intercrossed (third pyramiding generation) to increase the number of pyramided genes. For MAS, we used informative SSR markers in each cross. SSR markers were considered informative when the source resistance allele containing the target gene could be followed in the progeny, even in crosses between hybrids that both contained the same allele. Markers published in the ASR genetic mapping studies and in the consensus map of the soybean were used. We obtained plants containing from 2 to 4 genes pyramided per plant. These plants can be used as a source of multiple resistance in breeding programmes for obtaining soybean varieties with more durable resistance to ASR.

High‐throughput NGS‐based genotyping and phenotyping: Role in genomics‐assisted breeding for soybean improvement

“…The MAS (includes MABC and MARS) utilizes molecular markers known to be associated with a particular trait/phenotype to identify a desirable individual carrying favorable allele for the trait of interest (Jiang, 2013). However, MAS is applicable only for the major‐effect genes (Bhat et al, 2016); for example, most of the successful MAS‐based studies carried out earlier in soybean involved mainly the major‐effect QTLs/genes that govern large portion of phenotypic variation for the trait of interest (see details in Concibido et al, 1996; Gupta et al, 2017; Kim et al, 2020; Saghai Maroof et al, 2008; Viganó et al, 2018). In case of minor genes, which contribute only a small invisible phenotypic variation for the complex trait, MAS has not led to successful results in soybean (Bhat et al, 2016; Zhang et al, 2015).…”

Mapping of a soybean rust resistance in PI 594756 at the Rpp1 locus

“…Therefore, the sustainable development of ASR resistant cultivars might likely require the stacking of two or more Rpp genes in order to obtain effective protection against the majority of P. pachyrhizi pathotypes in the geographical target region. Stacking or pyramiding Rpp genes has been the focus of several studies, and has proven to enlarge the resistance spectrum while increasing the resistance level (Lemos et al 2011, Maphosa et al 2012, Viganó et al 2018, Yamanaka and Hossain, 2019.…”

Soybean‐Phakopsora pachyrhizi interactions: towards the development of next‐generation disease‐resistant plants

“…Recognition of an effector by an R protein results in a robust and localized form of innate immunity known as effector-triggered immunity (ETI) (Jones and Dangl, 2006). Most plant R proteins are nucleotide-binding leucine-rich repeat receptors (NLRs) (van Wersch et al, 2020). NLRs can be subdivided into two major categories, those containing coiled-coil (CC) or Toll/Interleukin receptor (TIR)-like amino (N)-terminal domains, known as CNLs and TNLs, respectively.…”