qRT9, a quantitative trait locus controlling root thickness and root length in upland rice
qRT9, a quantitative trait locus controlling root thickness and root length in upland rice
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DOI：
10.1093/jxb/erv076
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发表时间：
2015-05-01
影响因子：
6.9
通讯作者：
Zhao, Quanzhi
中科院分区：
文献类型：
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作者：
Li, Junzhou;Han, Yingchun;Zhao, Quanzhi
QRT9.从旱稻中克隆了一个控制根厚和根长的QTL。发现了一个具有两个功能多态位点的候选基因OsbHLH120，培育强健的根系是提高水稻抗旱性的重要策略。为了克隆与强根性状相关的基因，选育了根粗长于背景亲本乐府的陆稻渐渗系IL392。以乐府与IL392杂交组合的203个F-2：3群体为材料，在水培条件下检测到一个控制根粗和根长的数量性状基因座(QTL)qRT9。QRT9基因座对根厚和根长的贡献率分别为32.5%和28.1%。利用3185个F-2植株，通过替换作图，最终将qRT9缩小到11.5kb的区域。在该区域注释了一个可能的碱性螺旋-环-螺旋转录因子基因LOC_Os09g28210(命名为OsbHLH120)。11个陆稻和13个水稻的OsbHLH120序列表明，82位的单核苷酸多态(SNP)和628-642位的插入/缺失(Indel)会引起氨基酸的变化，并且在陆稻和水稻之间是保守的。表型分析表明，在水培条件下，这两个多态与根厚和根长显著相关。实时荧光定量聚合酶链式反应显示，OsbHLH120在聚乙二醇、盐和脱落酸胁迫下均有较强的诱导作用，但在聚乙二醇和盐胁迫下，IL392根中的表达高于乐府。QRT9基因座的成功分离，丰富了我们对旱稻避旱遗传基础的认识，为利用旱稻种质资源中有价值的基因选育避旱品种提供了机会。
qRT9. a QTL for root thickness and root length, was cloned from upland rice. The candidate gene OsbHLH120, with two functional polymorphic sites, was identified.Breeding for strong root systems is an important strategy for improving drought avoidance in rice. To clone genes responsible for strong root traits, an upland rice introgression line IL392 with thicker and longer roots than the background parent lowland rice Yuefu was selected. A quantitative trait locus (QTL), qRT9, controlling root thickness and root length was detected under hydroponic culture using 203 F-2:3 populations derived from a cross between Yuefu and IL392. The qRT9 locus explained 32.5% and 28.1% of the variance for root thickness and root length, respectively. Using 3185 F-2 plants, qRT9 was ultimately narrowed down to an 11.5kb region by substitution mapping. One putative basic helix-loop-helix (bHLH) transcription factor gene, LOC_Os09g28210 (named OsbHLH120), is annotated in this region. Sequences of OsbHLH120 in 11 upland rice and 13 lowland rice indicated that a single nucleotide polymorphism (SNP) at position 82 and an insertion/deletion (Indel) at position 628-642 cause amino acid changes and are conserved between upland rice and lowland rice. Phenotypic analysis indicated that the two polymorphisms were significantly associated with root thickness and root length under hydroponic culture. Quantitative real-time PCR showed that OsbHLH120 was strongly induced by polyethylene glycol (PEG), salt, and abscisic acid, but higher expression was present in IL392 roots than in Yuefu under PEG and salt stress. The successfully isolated locus, qRT9, enriches our knowledge of the genetic basis for drought avoidance and provides an opportunity for breeding drought avoidance varieties by utilizing valuable genes in the upland rice germplasm.