拟南芥矮小丛生突变体的分离与分子鉴定

顶端优势是指侧生分生组织的生长被主茎或主花序所抑制。最近的研究通过分离和鉴定顶端优势发生改变的突变体开始揭示顶端优势的分子机制。通过T-DNA标签法分离了拟南芥矮小丛生(bushy and dwarf l，budl)突变体。突变体植株的表型包括顶端优势丧失、株型矮小，表明budl突变体存在生长素代谢、运输或信号传导的缺陷。一个对生长素特异反应的启动子驱动的报告基因在budl中表达模式改变。生长素敏感性和运输能力的测定表明这两个过程在budl中均正常。以上结果显示budl表型是生长素代谢缺陷的结果。遗传分析表明BUDI为半显性突变且与一个T-DNA插入共分离，可通过iPCR方法分离。

Isolation and Characterization of an Arabidopsis Bushy and Dwarf Mutant

Apical dominance is a phenomenon that the growth of axillary meristems is inhibited by the primary shoot or inflorescence. Recent researches have begun to reveal the molecular mechanisms of apical dominance by isolating and identifying mutants with altered apical dominance. Here we report isolation of a bushy and dwarf 1 (bud1) mutant from Arabidopsis thaliana L. through a T_DNA tagging approach. The phenotypes of bud1 plants include loss of apical dominance, reduced plant size and dwarfism, suggesting that the bud1 mutant may be involved in auxin metabolism, transport or signalling. Using a reporter gene driven by an auxin_responsive promoter, we found that the expression pattern of auxin response element was altered in bud1. The auxin sensitivity and transport assay indicates that these two processes are normal in bud1. These results suggest that the bud1 phenotypes may result from an alteration in auxin metabolism. Genetic analysis demonstrates that bud1 is a semidominant mutant and cosegregates with a T_DNA insertion, which indicates that BUD1 gene could be cloned by iPCR approach.