title: Fine mapping of the qLOP2 and qPSR2-1 loci associated with chilling stress tolerance of wild rice seedlings.
abstract: Using leaf osmotic potential and plant survival rate as chilling-tolerant trait indices, we identified two major quantitative trait loci qLOP2 and qPSR2 - 1 (39.3-kb region) and Os02g0677300 as the cold-inducible gene for these loci. Chilling stress tolerance (CST) at the seedling stage is an important trait affecting rice production in temperate climate and high-altitude areas. To identify quantitative trait loci (QTLs) associated with CST, a mapping population consisting of 151 BC(2)F(1) plants was constructed by using chilling-tolerant Dongxiang wild rice (Oryza rufipogon Griff.) as a donor parent and chilling-sensitive indica as a recurrent parent. With leaf osmotic potential (LOP) and plant survival rate (PSR) as chilling-tolerant trait indexes, two major QTLs, qLOP2 (LOD = 3.8) and qPSR2-1 (LOD = 3.3), were detected on the long arm of chromosome 2 by composite interval mapping method in QTL Cartographer software, which explained 10.1 and 12.3% of the phenotypic variation, respectively. In R/QTL analyzed result, their major effects were also confirmed. Using molecular marker RM318 and RM106, qLOP2 and qPSR2-1 have been introgressed into chilling-sensitive varieties (93-11 and Yuefeng) by marker-assisted selection procedure (MAS), which resulted in 16 BC(5)F(3) BILs that chilling tolerance have significantly enhanced compare with wild-type parents (P < 0.01). Therefore, two large segregating populations of 11,326 BC(4)F(2) and 8,642 BC(4)F(3) were developed to fine mapping of qLOP2 and qPSR2-1. Lastly, they were dissected to a 39.3-kb candidate region between marker RM221 and RS8. Expression and sequence analysis results indicated that Os02g0677300 was a cold-inducible gene for these loci. Our study provides novel alleles for improving rice CST by MAS and contributes to the understanding of its molecular mechanisms.
authors.affiliation: College of Bioscience and Biotechnology and Jiangsu Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, Jiangsu Province, China, yzxiaoning@163.com.
authors.forename: Ning
authors.initials: N
authors.lastname: Xiao
authors.forename: Wei-nan
authors.initials: WN
authors.lastname: Huang
authors.forename: Ai-hong
authors.initials: AH
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Gao
authors.forename: Yu-hong
authors.initials: YH
authors.lastname: Li
authors.forename: Cun-hong
authors.initials: CH
authors.lastname: Pan
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Ji
authors.forename: Xiao-xiang
authors.initials: XX
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Dai
authors.forename: Zheng-yuan
authors.initials: ZY
authors.lastname: Dai
authors.forename: Jian-min
authors.initials: JM
authors.lastname: Chen
mesh_terms: D000483:Alleles; D002874:Chromosome Mapping; D003080:Cold Temperature; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D008040:Genetic Linkage; D012275:Oryza / Q000235:genetics*; D010641:Phenotype; D040641:Quantitative Trait Loci; D013312:Stress, Physiological
chemical_list: D018744:DNA, Plant