Most agriculturally important traits are regulated by genes known as quantitative trait loci (QTLs) derived from natural allelic variations. We here show that a QTL that increases grain productivity in rice, Gn1a, is a gene for cytokinin oxidase/dehydrogenase (OsCKX2), an enzyme that degrades the phytohormone cytokinin.Reduced expression of OsCKX2 causes cytokinin accumulation in inflorescence meristems and increases the number of reproductive organs, resulting in enhanced grain yield. QTL pyramiding to combine loci for grain number and plant height in the same genetic background generated lines exhibiting both beneficial traits. These results provide a strategy for tailormade crop improvement.
許多重要的農(nóng)藝性狀都是由來源于自然變異的數(shù)量性狀基因座（QTL）控制的。本文我們報道了一個增加水稻產(chǎn)量的QTL Gn1a，它編碼一個降解植物激素細胞分裂素的細胞分裂素氧化酶/脫氫酶(OsCKX2)。OsCKX2的表達下降導(dǎo)致細胞分裂素在花序分生組織中累積，增加生殖器官的數(shù)目，最終提高水稻的產(chǎn)量。通過QTL聚合將控制水稻粒數(shù)和株高的QTL聚合到同一個遺傳背景下，獲得了具有各種優(yōu)良性狀的株系。這些結(jié)果為改良作物特定性狀提供了一種策略。
結(jié)果：QTL分析；QTL克隆；OsCKX2的分子分析；QTL聚合；QTL在新的綠色革命中的應(yīng)用前景。