Identification of rice blast resistance candidate genes based on integrating Meta-QTL and RNA-seq analysis

Abstract

: Magnaporthe oryzae seriously devastates rice production, and resistant cultivars can lose resistance within a few years due to the pathogenic variability of M. oryzae. Therefore, it is essential to explore continuously novel blast-resistance genes for breeding broad-spectrum resistance cultivars. In this study, firstly, 50 Meta-QTLs (including at least 2 original QTLs) were identified on 12 chromosomes by meta-analysis of blast-resistance 783 QTLs from 43 literatures. The average interval distance was 0.87 Mb in these Meta-QTLs, which contained a total of 4718 interval genes. Subsequently, based on integrated analysis of blast-resistance Meta-QTLs and RNA-seq, the result identified 2193 common genes which were not only located on blast-resistance Meta-QTLs, but also significantly differentially expressed in response to the M. oryzae . Among them, 22 cloned genes had been reported to be involved in defense responses to M. oryzae and other stresses. Fur-thermore, 99 resistance gene analogues (RGA) and 112 transcription factors (TF) were screened out from the above common genes, which were utilized to construct gene co-expression networks (GCEN). Based on the Top 20 of the connection degrees, hub genes were identified in the GCEN. Among them, OsJAMyb , bsr-d1 , and OsWRKY76 had been reported to be against rice blast, and OsSPL9 was related to resistance to rice stripe virus. The left hub genes were considered as important potential resistance genes which need further functional verification to prepare for breeding broad-spectrum resistance rice cultivars.