Dissection of the Genetic Basis of Rice Panicle Architecture Using a Genome-wide Association Study
Shaoxing Bai,
Jun Hong,
Ling Li,
Su Su,
Zhikang Li,
Wensheng Wang,
Fengli Zhang,
Wanqi Liang,
Dabing Zhang
Affiliations
Shaoxing Bai
Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University
Jun Hong
Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University
Ling Li
Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University
Su Su
Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University
Zhikang Li
Institute of Crop Sciences, Chinese Academy of Agricultural Sciences
Wensheng Wang
Institute of Crop Sciences, Chinese Academy of Agricultural Sciences
Fengli Zhang
Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University
Wanqi Liang
Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University
Dabing Zhang
Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University
Abstract Panicle architecture is one of the major factors influencing productivity of rice crops. The regulatory mechanisms underlying this complex trait are still unclear and genetic resources for rice breeders to improve panicle architecture are limited. Here, we have performed a genome-wide association study (GWAS) to analyze and identify genetic determinants underlying three panicle architecture traits. A population of 340 rice accessions from the 3000 Rice Genomes Project was phenotyped for panicle length, primary panicle number and secondary branch number over two years; GWAS was performed across the whole panel, and also across the japonica and indica sub-panels. A total of 153 quantitative trait loci (QTLs) were detected, of which 5 were associated with multiple traits, 8 were unique to either indica or japonica sub-panels, while 37 QTLs were stable across both years. Using haplotype and expression analysis, we reveal that genetic variations in the OsSPL18 promoter significantly affect gene expression and correlate with panicle length phenotypes. Three new candidate genes with putative roles in determining panicle length were also identified. Haplotype analysis of OsGRRP and LOC_Os03g03480 revealed high association with panicle length variation. Gene expression of DSM2, involved in abscisic acid biosynthesis, was up-regulated in long panicle accessions. Our results provide valuable information and resources for further unravelling the genetic basis determining rice panicle architecture. Identified candidate genes and molecular markers can be used in marker-assisted selection to improve rice panicle architecture through molecular breeding.
