Abstract
BackgroundThe rice black-streaked dwarf virus (RBSDV) disease causes severe rice yield losses in Eastern China and other East Asian countries. Breeding resistant cultivars is the most economical and effective strategy to control the disease. However, few varieties and QTLs for RBSDV resistance have been identified to date.ResultsIn this study, we conducted a genome-wide association study (GWAS) on RBSDV resistance using the rice diversity panel 1 (RDP1) cultivars that were genotyped by a 44,000 high-density single nucleotide polymorphism (SNP) markers array. We found that less than 15% of these cultivars displayed resistance to RBSDV when tested under natural infection conditions at two locations with serious RBSDV occurrence. The aus, indica and tropical japonica sub-populations displayed higher RBSDV resistance than the aromatic and temperate japonica sub-populations. In particular, we identified four varieties that displayed stable levels of RBSDV resistance at all testing locations. GWAS identified 84 non-redundant SNP loci significantly associated with RBSDV resistance at two locations, leading to the identification of 13 QTLs for RBSDV resistance. Among them, qRBSDV-4.2 and qRBSDV-6.3 were detected at both locations, suggesting their resistance stability against environmental influence. Field disease evaluations showed that qRBSDV-6.3 significantly reduces RBSDV disease severity by 20%. Furthermore, introgression of qRBSDV-6.3 into two susceptible rice cultivars by marker-assisted selection demonstrated the effectiveness of qRBSDV-6.3 in enhancing RBSDV resistance.ConclusionsThe new resistant cultivars and QTLs against RBSDV disease identified in this study provide important information and genetic materials for the cloning of RBSDV resistance genes as well as developing RBSDV resistant varieties through marker-assisted selection.
Highlights
The rice black-streaked dwarf virus (RBSDV) disease causes severe rice yield losses in Eastern China and other East Asian countries
We concluded that the disease incidence (DI) data from Yutai and Kaifeng were more suitable for further screening of resistant germplasm and identifying RBSDV resistance genes
We evaluated the rice diversity panel 1 (RDP1) cultivars for resistance to RBSDV using the natural infection method at five testing locations where the RBSDV disease was prevalent in the previous years (Zhou 2013)
Summary
The rice black-streaked dwarf virus (RBSDV) disease causes severe rice yield losses in Eastern China and other East Asian countries. The rice black-streaked dwarf virus (RBSDV) disease is spread by small brown planthoppers (Laodelphax striatellus Fallén, SBPH) (Shikata and Kitagawa 1977; Ruan et al 1984). The RBSDV disease is expanding in Eastern China and other East Asian countries, resulting in severe yield losses (Sun et al 2013; Zhou et al 2015). Breeding resistant cultivars are believed to be the more economical and effective strategies to control the RBSDV disease compared to pesticides spraying to control the transmission vector SBPH (Zhou et al 2015; Sun et al 2017). Only a few studies reported the mapping of resistance genes and quantitative trait loci (QTLs) to RBSDV to date (Pan et al 2009; Wang et al 2010; Zheng et al 2012; Li et al 2013; Zhou et al 2015; Zhang et al 2016; Sun et al 2017)
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