Li Fuzhen, Hu Guocheng, Fu Yaping, Si Huamin, Bai Xuemei, Sun Zongxiu
College of Life Sciences, Zhejiang University, Hangzhou, China.
Genome. 2005 Aug;48(4):738-46. doi: 10.1139/g05-030.
A rice mutant, designated pse(t) (premature senescence, tentatively), was isolated from a T-DNA-inserted transgenic population. Senescence advanced more markedly in pse(t) than in wild-type ('Zhonghua 11', japonica) plants. Genetic analysis of pse(t) revealed that the premature senescence mutation was controlled by a single recessive nuclear gene, but that it was not induced by T-DNA insertion. In an effort to understand the genetic and molecular basis underlying premature senescence in rice, a map-based cloning strategy was used to localize Pse(t). High-resolution mapping of the Pse(t) locus was carried out using simple sequence repeat (SSR) and cleaved amplified polymorphic sequence (CAPS) markers. An F2 population, comprising 1691 pse(t) individuals derived from a cross of the pse(t) mutant with 'Longtepu' (indica), was constructed. Several new polymorphism markers were developed in this study. Genetic linkage analysis showed that the Pse(t) gene was located on the long arm of chromosome 7. It was found that the Pse(t) gene cosegregated with 3 markers and was flanked by markers SS22 and PP21. Thus, the Pse(t) gene is located within a genetic distance of 0.15 cM, corresponding to a physical distance of 220 kb. These findings provide the basic information that can be used for the final isolation of this gene in the rice premature-senescence pathway.
从一个T-DNA插入的转基因群体中分离出一个水稻突变体，暂命名为pse(t)（早衰）。pse(t)植株的衰老比野生型（粳稻‘中华11’）植株更明显。对pse(t)的遗传分析表明，早衰突变由一个隐性核基因控制，但并非由T-DNA插入诱导。为了了解水稻早衰的遗传和分子基础，采用图位克隆策略对Pse(t)进行定位。利用简单序列重复（SSR）和酶切扩增多态性序列（CAPS）标记对Pse(t)基因座进行了高分辨率定位。构建了一个由1691个pse(t)个体组成的F2群体，这些个体来自pse(t)突变体与‘龙特浦’（籼稻）的杂交。本研究开发了几个新的多态性标记。遗传连锁分析表明，Pse(t)基因位于第7染色体长臂上。发现Pse(t)基因与3个标记共分离，两侧分别为标记SS22和PP21。因此，Pse(t)基因位于0.15 cM的遗传距离内，对应物理距离为220 kb。这些发现为最终分离水稻早衰途径中的该基因提供了基础信息。
