水稻资源开花期耐热性的全基因组关联分析

水稻在开花期对高温非常敏感,挖掘耐热种质并解析耐热性的遗传机制,有助于水稻的耐热性遗传改良。本研究选取205份国内外种质资源,在抽穗开花期对遇高温的稻穗进行标记,以高温下标记穗的结实率作为耐热指标,结合高密度SNP标记进行全基因组关联分析并初步预测候选基因。结果表明:不同水稻种质的耐热性差异明显,高温下的结实率最低为19.0%,平均值为64.0%,中位值为65.9%,最高值为86.6%,其中06-32、剪刀齐、娄早籼5号等17份种质的耐热性较强;全基因组关联分析共筛选到130个与耐热性显著关联的SNP标记,并鉴定到18个耐热QTL,其中6个QTL与已报道的耐热相关QTL共定位;qHT4-6与耐热性的关联度最高,根据该区间lead SNP的单倍型分类,G单倍型材料的开花期耐热性显著强于A单倍型材料,该区间附近有7个基因可能受高温调控。

Genome Wide Association Study of Heat Tolerance at the Anthesis Stage in Rice

Rice(Oryza sativa L.)is sensitive extremely to heat stress at the flowering stage.Screening for rice genetic resources with heat tolerance at the flowering stage and identifying the quantitative trait locus(QTL)become important on the improvement of heat tolerance.In this study,205 rice lines were evaluated for heat tolerance in the field.The rice panicles which flowered under high temperature were tagged for quantifying the spikelet fertility(SF)which was subjected for the genome wide association study(GWAS).The broad variation on the spikelet fertility was observed in heat tolerance among rice accessions,which ranged from 19.0%to 86.6%,with an average of 64.0%and a median of 65.9%.Rice lines such as 06-32,Jiandaoqi and Louzaoxian No.5 were tolerant against heat stress and they could be used as candidate donor lines in future rice breeding.A total of 18 QTL with 130 SNPs were detected to be significantly associated with heat tolerance.Six QTL were co-localized with the loci which were previously identified.A novel QTL,qHT4-6,with the lowest P-value was selected for the allelic variation analysis.The heat tolerance of rice lines with G-allele of the lead SNP were significantly stronger than those of A-allele lines.As a result,seven genes within the interval of qHT4-6 were proposed to be candidate responding to the heat stress.