Feng Z, Kang H, Li M, Zou L, Wang X, Zhao J, Wei L, Zhou N, Li Q, Lan Y, Zhang Y, Chen Z, Liu W, Pan X, Wang GL, Zuo S.

Rice (N Y). 2019 Jul 15;12(1):49. doi: 10.1186/s12284-019-0310-1.

Abstract

BACKGROUND:

The 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.

RESULTS:

In 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.

CONCLUSIONS:

The 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.

See https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6629753/

Figure 4: Genome-wide association study of RBSDV resistance of 305 rice varieties. a and b Manhattan plots of MLM for the data obtained at Kaifeng (a) and Yutai (b). Black horizontal lines indicate the genome-wide significance threshold. Arrows indicate regions containing at least 2 significant-association markers which were designed as QTLs for RBSDV resistance. The two regions highlighted by rectangles indicate they were detected at both locations with consistent results.