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Dessection of developmental program in rice

水稻发育程序解析

基本信息

批准号：
11306001
负责人：
NAGATO Yasuo
金额：
$ 26.07万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

We have already revealed that at least four loci (SHL1〜SHL4) are involved in the initiation of shoot apical meristem (SAM) in rice. To address how SHL genes are associated with the maintenance of SAM, we have newly identified three weak alleles, shl2-6〜shl2-8, of SHL2 and one weak allele, shl1-3, of SHL1. It is revealed that SHL1 and SHL2 genes are indispensable for the maintenance of SAM. In addition, they also regulate the developmental pattern of leaf primordia. Weak shl alleles developed abnormal seedlings producing small thread-like leaves in irregular phyllotaxy. The seedling phenotype of weak shl alleles is similar to that of sho mutants. Double mutant of shl2-6 sho2 suggests that SHO2 function upstream of SHO2.For dissecting developmental mechanism of panicle and flower, we have analyzed apo1 mutants showing abnormal organization of panicle and flowers. The apo1 produced terminal flowers due to the precocious transformation of meristem identity in rachis and branches. In apo1 flowers, lodicules were increased but stamens were decreased. A large number of pistils were produced indeterminately. These phenotypes suggest that APO1 gene regulates temporal y the transformation of meristem identity in reproductive phase.To elucidate the program for root formation, we identified mutants defective in crown root (adventitious root) formation. Some mutants have defect in the elongation of root primordia, and the other failed to form root primordia. Thus, there exists a complex cascade of many genes in root formation.

我们已经揭示了至少有4个基因(SHL1~SHL4)参与水稻顶端分生组织(SAM)的发生。为了研究SHL基因如何与SAM的维持相关，我们新发现了SHL2的三个弱等位基因shl2-6~shl2-8和SHL1的一个弱等位基因shl1-3。结果表明，SHL1和SHL2基因对SAM的维持是不可或缺的。此外，它们还调节叶原基的发育模式。在不规则的叶序中，弱的shl等位基因发育出产生细丝状叶片的异常幼苗。弱shl等位基因的苗期表型与sho突变体相似。Sho2的双突变体表明SHO2在SHO2的上游起作用。为了剖析穗和花的发育机制，我们分析了表现出穗和花组织异常的apo1突变体。Apo1由于轴和枝中分生组织特性的早熟转化而产生顶花。载脂蛋白1花的鳞片数增加，雄蕊数减少。不确定地产生了大量雌蕊。这些表型表明，APO1基因调控生殖阶段分生组织特性的时间转换。为了阐明根形成的程序，我们鉴定了冠根(不定根)形成缺陷的突变体。一些突变体的根原基伸长存在缺陷，另一些突变体未能形成根原基。因此，在根的形成过程中存在着许多基因的复杂级联。