拟南芥ABA敏感突变体asm1的分离与鉴定

以拟南芥(Arabidopsis thaliana)为研究材料,从T-DNA突变体库中筛选分离得到1株脱落酸(ABA)敏感突变体asm1(ABA sensitive mutant 1,asm1),在含有ABA的培养基中,与野生型相比,asm1突变体的根伸长明显受到抑制,且其种子萌发结果显示asm1对ABA同样表现出敏感特性。在生长发育方面,asm1突变体抽苔时间提前,植株矮化,并且荚果长度明显小于野生型。利用远红外成像系统分析发现,在干旱胁迫下asm1突变体叶面温度高于野生型;失水率分析显示突变体失水率降低以及水分散失减少。遗传学分析表明,asm1是单基因隐性突变且与一个T-DNA插入共分离;通过图位克隆成功获得候选基因ASM1。RT-PCR结果显示,在突变体中ASM1的表达受到抑制,并且能够调控多种ABA信号通路和胁迫应答基因的表达水平。研究结果表明,ASM1可能参与调控ABA信号转导并应答干旱胁迫。

Isolation and Characterization of ABA Sensitive Mutant asm1 in Arabidopsis

In Arabidopsis,we screened and isolated a mutant asm1 (ABA sensitive mutant 1,asm1) in the T-DNA mutant library,on ABA medium asm1 was more sensitive to ABA than the wild type on root elongation,further study showed on seed germination asm1 germinated earlier than WT.In terms of growth and development,asm1 exhibited early-flowering and dwarf phenotypes,the size of siliques of the mutants was shorter and more stunted compared with the wild type.Using far infrared imaging system we found that the leaf temperature of asm1 mutant was higher than the wild type under drought stress,water loss rate of mutant was lower and water loss was reduced.Genetic analysis revealed asm1 was a single recessive-gene mutant and cosegregated with a T-DNA tag,We used map-based cloning to identify the candidate gene ASM1.RT-PCR results showed that in the mutant the expression of ASM1 was inhibited,and could regulate expression levels of a variety of ABA signaling and stress response genes.These results indicate that ASM1 may be involved in the regulation of ABA signal transduction and response to drought stress.