Evaluation of near-isogenic lines for drought resistance QTL and fine mapping of a locus affecting flag leaf width, spikelet number, and root volume in rice
Evaluation of near-isogenic lines for drought resistance QTL and fine mapping of a locus affecting flag leaf width, spikelet number, and root volume in rice
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近等基因系的抗旱QTL评价以及影响水稻剑叶宽度、小穗数和根体积的位点精细定位
DOI：
10.1007/s00122-011-1629-1
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发表时间：
2011-09-01
影响因子：
5.4
通讯作者：
Xiong, Lizhong
中科院分区：
文献类型：
--
作者：
Ding, Xipeng;Li, Xiaokai;Xiong, Lizhong
干旱胁迫是作物生产的主要限制因素，由于抗旱性状的复杂性，抗旱育种非常具有挑战性。以往的水稻研究表明，旱地粳稻品种IRAT109的抗旱性优于低地粳稻品种珍山97。许多数量性状位点（QTL）以前已经用这两个基因型衍生的重组自交系群体进行了定位。本研究构建了17个抗旱相关QTL的近等基因系，并对这些近等基因系在干旱和正常条件下的表型变异进行了研究。其中14个NILs在至少一种情况下与复发亲本存在显著的表型差异，9个NILs在两种情况下均存在显著差异。在排除抽穗日期对抗旱性的影响后，只有4个NILs携带7个QTL（4个为相同产量相关性状QTL， 3个为相同或相似根系性状QTL）显示与原始QTL定位结果一致的差异。其中的一个品系（N19）含有4号染色体上的QTL sqfsr4，该QTL控制每分蘖根体积，并与旗叶宽度和每穗小穗数共分离。利用来自N19的群体，qfsr4被定位到一个38kb的区域，该区域包含三个开放阅读框，包括先前表征的narrow LEAF 1（NAL1）基因。NAL1控制叶片宽度，也影响叶脉模式和极性生长素运输，是qfsr4最有希望的候选基因。我们的研究结果强调了NILs的开发对于确定影响复杂性状（如抗旱性）的QTL的重要性。
Drought stress is a major limiting factor for crop production and breeding for drought resistance is very challenging due to the complex nature of this trait. Previous studies in rice suggest that the uplandjaponicavariety IRAT109 shows better drought resistance than the lowlandindicavariety Zhenshan 97. Numerous quantitative trait loci (QTL) have been previously mapped using a recombinant inbred line population derived from these two genotypes. In this study, near-isogenic lines (NILs) for 17 drought resistance-related QTL were constructed and phenotypic variations of these NILs were investigated under drought and normal conditions. Fourteen of these NILs showed significant phenotypic differences relative to the recurrent parent under at least one of the conditions and nine NILs showed significant differences under both conditions. After eliminating the effect of heading date on drought resistance, only four NILs carrying seven QTL (four for the same grain yield-related traits and three for the same or similar root traits QTL) showed differences consistent with the original QTL mapping results. One of these lines (N19) containsqFSR4, a QTL on chromosome 4 controlling root volume per tiller and co-segregating with flag leaf width and spikelet number per panicle. Using a population derived from N19,qFSR4was mapped to a 38-kb region containing three open reading frames including the previously characterizedNARROW LEAF 1(NAL1) gene.NAL1, which controls leaf width and also affects vein patterning and polar auxin transport, is the most promising candidate genes forqFSR4. Our results underscore the importance of the development of NILs to confirm the identification of QTL affecting complex traits such as drought resistance.