Kashiwagi Takayuki, Ishimaru Ken
National Institute of Agrobiological Sciences, Kannondai 2, Tsukuba, Ibaraki 305-8602, Japan.
Plant Physiol. 2004 Feb;134(2):676-83. doi: 10.1104/pp.103.029355. Epub 2004 Jan 22.
We identified a new locus responsible for increased pushing resistance of the lower part of rice (Oryza sativa) and analyzed its physiological function to understand how to improve lodging resistance in rice. Quantitative trait loci (QTLs) controlling pushing resistance of the lower part were analyzed in a population of backcross inbred lines of japonica Nipponbare x indica Kasalath plants cut out at 40 cm to exclude the effect of the weight of the upper parts. Five QTLs for pushing resistance were detected; only one QTL from Kasalath on chromosome 5 (prl5) had a positive effect. The likelihood odds ratio curve of prl5 echoed that for lodging resistance by typhoon. We selected three near-isogenic lines (NILs) in which the chromosomal region of prl5 was substituted with that of Kasalath in the Nipponbare background. The dry weights and densities and the contents of accumulated carbohydrate in stems below 40 cm (lower stems) in each NIL were significantly higher than those of Nipponbare. There was no difference between Nipponbare and the NILs in yield, root characteristics, or the weights of the upper parts. Pushing resistance of the lower part and lodging resistance in the NILs were up to twice as high as in Nipponbare. These results suggest that prl5 might affect the characteristics of the lower stems of the NILs, thus increasing lodging resistance.
我们鉴定出一个导致水稻（Oryza sativa）下部抗倒伏能力增强的新基因座，并分析了其生理功能，以了解如何提高水稻的抗倒伏性。在粳稻日本晴与籼稻Kasalath回交自交系群体中，对40厘米处切断的植株下部抗倒伏性的数量性状基因座（QTL）进行了分析，以排除上部重量的影响。检测到5个抗倒伏QTL；仅位于第5号染色体上来自Kasalath的一个QTL（prl5）具有正向效应。prl5的似然比曲线与台风抗倒伏性的曲线相似。我们选择了三个近等基因系（NIL），在日本晴背景下，prl5的染色体区域被Kasalath的染色体区域所取代。每个NIL中40厘米以下茎（下部茎）的干重、密度和积累碳水化合物含量均显著高于日本晴。日本晴与NIL在产量、根系特征或上部重量方面没有差异。NIL下部的抗倒伏性和抗倒伏能力比日本晴高出两倍。这些结果表明，prl5可能影响NIL下部茎的特性，从而提高抗倒伏性。
