Abstract

Key message

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.

Abstract

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 BC₅F₂, BC₅F₃, and BC₅F₄ 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 BC₅F₂, BC₅F₃, and BC₅F₄ generations, respectively. Using homozygous recombinants screened from larger BC₆F₂ and BC₆F₃ 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.

中文翻译：

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使用Oryza rufipogon Griff对qHTB1-1 QTL进行精细映射，从而在启动阶段赋予耐热性。渗入线

摘要

关键信息

所述qHTB1 - 1 QTL，在控制水稻孕穗期耐热性，被细映射到包含八个候选基因47.1 kb的区域。在热胁迫下，两个位置候选基因显示出表达水平的显着变化。

抽象

孕穗期的高温胁迫可能会严重限制水稻的产量。种间先进之间回交群体稻L.品种R53和野生野生稻格里夫加入HHT4用作源材料来开发一组染色体片段导入系阐明的遗传机制qHTB1 - 1个QTL在耐热性。单染色体片段导入系，IL01-15，被用于开发的映射次级群体qHTB1 - 1 1号染色体上在孕穗期耐热性。使用BC ₅ F ₂，BC ₅ F₃，和BC ₅ ˚F ₄群，我们首次证实qHTB1 - 1和验证的表型效应。所述qHTB1 - 1 QTL解释13.1％，16.9％，而在BC中观察到的表型变异的17.8％₅ ˚F ₂，BC ₅ ˚F ₃和BC ₅ ˚F ₄分别代，。使用从较大的BC筛选纯合重组体₆ ˚F ₂和BC ₆ ˚F ₃群，qHTB1 - 1在标记RM11633和RM11642之间的47.1 kb区域内精细定位。在该区域中注释了八个推定的预测基因，并预测了六个基因编码表达的蛋白质。这六个基因的表达模式表明，与R53相比，IL01-15中的热胁迫高度诱导了LOC_Os01g53160和LOC_Os01g53220。R53和IL01-15之间的LOC_Os01g53160和LOC_Os01g53220的基因编码区的序列比较表明，外显子中分别有一个同义SNP和两个不同义SNP。我们的研究结果用于鉴定潜在的基因提供了基础qHTB1 - 1并且指示连接到标记qHTB1 -通过标记辅助选择，可以在启动阶段使用1个基因座来提高水稻的耐热性。