Rice National Engineering Laboratory (Nanchang), Jiangxi Research and Development Center of Super Rice, Jiangxi Academy of Agricultural Sciences, Nanchang, 330200, China.
Institute of Soil Fertilizer and Resource Environment, Jiangxi Academy of Agricultural Sciences, Nanchang, 330200, China.
Theor Appl Genet. 2020 Apr;133(4):1161-1175. doi: 10.1007/s00122-020-03539-7. Epub 2020 Jan 27.
The qHTB1-1 QTL, controlling heat tolerance at the booting stage in rice, was fine mapped to a 47.1 kb region containing eight candidate genes. Two positional candidate genes showed significant changes in expression levels under heat stress. High-temperature stress at the booting stage has the potential to significantly limit rice production. An interspecific advanced backcrossed population between the Oryza sativa L. cultivar R53 and the wild Oryza rufipogon Griff accession HHT4 was used as the source material to develop a set of chromosome segment introgression lines to elucidate the genetic mechanism of the qHTB1-1 QTL in heat tolerance. A single-chromosome-segment introgression line, IL01-15, was used to develop secondary populations for the mapping of qHTB1-1 on chromosome 1 for heat tolerance at the booting stage. Using the BCF, BCF, and BCF populations, we first confirmed qHTB1-1 and validated the phenotypic effect. The qHTB1-1 QTL explained 13.1%, 16.9%, and 17.8% of the phenotypic variance observed in the BCF, BCF, and BCF generations, respectively. Using homozygous recombinants screened from larger BCF and BCF populations, qHTB1-1 was fine mapped within a 47.1 kb region between markers RM11633 and RM11642. Eight putative predicted genes were annotated in the region, and six genes were predicted to encode expressed proteins. The expression patterns of these six genes demonstrated that LOC_Os01g53160 and LOC_Os01g53220 were highly induced by heat stress in IL01-15 compared to R53. Sequence comparison of the gene-coding regions of LOC_Os01g53160 and LOC_Os01g53220 between R53 and IL01-15 revealed one synonymous and two nonsynonymous SNPs in exons, respectively. Our results provide a basis for identifying the genes underlying qHTB1-1 and indicate that markers linked to the qHTB1-1 locus can be used to improve the heat tolerance of rice at the booting stage by marker-assisted selection.
qHTB1-1 数量性状位点控制水稻抽穗期的耐热性，被精细定位到一个包含八个候选基因的 47.1 kb 区域。两个定位候选基因在热胁迫下表达水平有显著变化。抽穗期高温胁迫有可能显著限制水稻产量。利用籼稻品种 R53 和野生稻 O. rufipogon Griff accession HHT4 的种间先进回交群体作为材料，开发了一套染色体片段导入系，以阐明 qHTB1-1 在耐热性中的遗传机制。利用单染色体片段导入系 IL01-15，开发了次级群体，用于在第 1 染色体上对抽穗期耐热性的 qHTB1-1 进行作图。利用 BCF、BCF 和 BCF 群体，我们首先确认了 qHTB1-1，并验证了表型效应。qHTB1-1 解释了 BCF、BCF 和 BCF 代观察到的表型方差的 13.1%、16.9%和 17.8%。利用从较大的 BCF 和 BCF 群体中筛选出的纯合重组体，将 qHTB1-1 精细定位到标记 RM11633 和 RM11642 之间的 47.1 kb 区域内。该区域注释了 8 个推定的预测基因，其中 6 个基因预测编码表达蛋白。这些 6 个基因的表达模式表明，与 R53 相比，LOC_Os01g53160 和 LOC_Os01g53220 在 IL01-15 中受高温胁迫高度诱导。R53 和 IL01-15 之间 LOC_Os01g53160 和 LOC_Os01g53220 的基因编码区序列比较显示，外显子中分别有一个同义 SNP 和两个非同义 SNP。我们的结果为鉴定 qHTB1-1 基因提供了依据，并表明与 qHTB1-1 位点连锁的标记可用于通过标记辅助选择提高水稻抽穗期的耐热性。
