拟南芥NO敏感突变体rsn1的特性分析

Characterization of Nitric Oxide Sensitive Mutant rsn1 in Arabidopsis

为了深入研究信号分子NO在植物中的调控机制,以拟南芥(Arabidopsis thaliana)为研究材料,从甲基磺酸乙酯(EMS)诱变获得的突变体库中筛选得到1株对一氧化氮(NO)敏感的突变体rsn1(Root sensitive to NO),对比分析突变体根对NO的敏感程度、气孔对脱落酸(ABA)的反应等指标,并且利用图位克隆技术初步定位突变基因。结果表明,尽管在正常生长条件下rsn1突变体的萌发率与野生型没有明显区别,但根对NO胁迫敏感,在50μmol/L硝普钠(SNP)处理下,野生型拟南芥的相对根长为48.7%,而突变体rsn1的相对根长仅为5.3%;通过分析气孔对ABA的敏感程度发现,rsn1对ABA调控气孔关闭不敏感,在10μmol/L ABA处理下突变体rsn1的气孔直径是野生型的1.9倍,而在正常条件下突变体rsn1的气孔直径与野生型差异不大,且突变体rsn1的失水率高于野生型拟南芥;遗传分析表明,rsn1是一个单基因隐性突变体;通过图位克隆初步判断突变位点在第5号染色体上。

In order to investigate the molecular regulation mechanism of nitric oxide(NO)in plant,using Arabidopsis as research materials,we screened NO-sensitive mutants and isolated a mutant rsn1(root sensitive to NO)from the EMS mutant library.The sensitivity of rsn1 mutant roots to NO and stomatal response to abscisic acid(ABA)were compared and analyzed,and the mutant genes were preliminarily located by map-based cloning.The results were as follows:the rsn1 root was more sensitive to NO stress compared with the wild type,though the germination rate of rsn1 mutant was not significantly different from that of wild type under normal growth conditions.Under 50μmol/L SNP treatment,the relative root length of wild type(as compared with root length in normal growth)was 48.7%,whereas the relative root length of mutant was 5.3%.By analyzing the sensitivity of stomata to ABA,it was found that rsn1 was insensitive to the regulation of stomatal closure by ABA.The stomatal diameter of rsn1 mutant was 1.9 times that of wild type under 10μmol/L ABA treatment,though the stomatal diameter of rsn1 mutant was similar to that of wild type under normal conditions,and the water loss rate of rsn1 mutant was higher than that of wild type Arabidopsis.Genetic analysis suggested that rsn1 was a single recessive mutant,and the mutation site was initially designated on chromosome 5 by map-based cloning.