Ashikari Motoyuki, Sakakibara Hitoshi, Lin Shaoyang, Yamamoto Toshio, Takashi Tomonori, Nishimura Asuka, Angeles Enrique R, Qian Qian, Kitano Hidemi, Matsuoka Makoto
Bioscience and Biotechnology Center, Nagoya University, Nagoya 464-8601, Japan.
Science. 2005 Jul 29;309(5735):741-5. doi: 10.1126/science.1113373. Epub 2005 Jun 23.
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.
大多数具有重要农业意义的性状是由源自自然等位基因变异的数量性状基因座（QTL）调控的。我们在此表明，水稻中一个提高谷物产量的QTL，Gn1a，是一种细胞分裂素氧化酶/脱氢酶（OsCKX2）的基因，该酶可降解植物激素细胞分裂素。OsCKX2表达的降低导致细胞分裂素在花序分生组织中积累，并增加生殖器官的数量，从而提高谷物产量。在相同遗传背景下将控制粒数和株高的基因座进行QTL聚合，产生了兼具两种有益性状的品系。这些结果为定制作物改良提供了一种策略。
