Comparative analysis of soybean genotype resistance to Heterodera glycines and Meloidogyne species via resistance gene analogs

Abstract

ABSTRACT. Nematodes are important pests of soybean throughout the world and cause high yield losses. As a control strategy, the identification of resistance genes is an important aim of breeding studies. Plants possess resistance genes (R), which are responsible for the recognition of pathogens and activation of the defense system. R genes and resistance gene analogs (RGAs) possess conserved domains, from which nucleotide-binding site is the most common. Using degenerate primers originating from these domains, it is possible to identify and isolate sequences of R and RGA genes. In this study, soybean genotypes resistant to the nematodes Heterodera glycines, Meloidogyne incognita, M. javanica, and M. enterolobii were compared by the use of RGAs and simple sequence repeat (SSR) markers. Forty-six soybean genotypes were studied, including plant introductions (PIs), commercial crops, and source of resistance genotypes. Thirteen combinations of RGA primers and different SSRs linked to QTLs were used to confirm resistance to soybean cyst nematodes (SCN). Fragments associated with resistance to the studied nematodes were amplified in the source of resistance and PI genotypes. RGA markers were efficient at distinguishing groups of genotypes that were resistant and susceptible to Meloidogyne spp and SCN. Combinations of specific primers were identified through their ability to amplify nucleotide sequences from possible resistance candidate genes. SSR markers contributed to the analysis of SCN race specificity, showing that the QTLs identified by these markers are distinct from those identified by RGA markers.

Integrated Omic Approaches Reveal Molecular Mechanisms of Tolerance during Soybean and Meloidogyne incognita Interactions

“…The introgression of the PI 595099 soybean genotype with a high level of resistance to M. incognita was developed by the Georgia Agricultural Experiment Station (EUA), while BRS 133, by contrast, is a susceptible genotype developed by the National Soybean Research Center—Embrapa Soybean (Brazil). Both genotypes are agriculturally important and have been used in soybean breeding programs and in studies to identify genetic resistance to parasitic nematodes [ 47 , 48 , 49 , 50 , 51 , 52 , 53 ]. Recently, an increasing number of studies exploring the mechanisms underlying the resistance and susceptibility of diverse crops to M. incognita have been performed using omic approaches [ 51 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 ].…”

Relationship between Psidium species (Myrtaceae) by resistance gene analog markers: focus on nematode resistance

“…The conserved protein domains permit degenerate primers to be used in studies aiming to identify resistance genes in different species (Vieira et al, 2016); the so-called RGA markers. In this context, the main objective of this study was to characterize Psidium species using genomic regions associated with pathogen resistance in plants using RGA markers from the NBS, GLPLAL, and RNBS-B domains.…”