异三聚体G蛋白在IAA诱导的拟南芥根生长发育中的作用

The Role of Heterotrimeric G Protein in Root Growth of IAA Induced Arabidopsis thaliana

以拟南芥的野生型（ws）和异三聚体G蛋白α亚基基因GPA1缺失突变体（gpa1-1,gpa1-2）和超表达突变体（wGα,cGα）为材料,通过施加不同浓度（0~0.8 mg/L）的IAA处理,对拟南芥根生长发育的一些形态指标进行了观测比较。结果表明：①随着培养基中IAA浓度的不断升高,5种基因型主根的伸长生长都受到抑制,且抑制作用随浓度升高而增强;4种突变体和野生型主根的生长在相同浓度IAA处理下,无明显差异;②IAA在一定浓度范围内,对拟南芥侧根的生长发育起促进作用;在相同浓度IAA诱导的侧根生长中,缺失突变体明显比野生型侧根多,超表达突变体比野生型侧根少。初步证明,G蛋白不参与主根生长发育的调节,而在侧根生长发育中可能起负调节作用。

The wild type Arabidopsis thaliana and its mutants in which heterotrimeric G protein a subunit gene GPA1 was null （gpal-1 ,gpal-2） or overexpressed （wGa, cGa） were used as main mate-rials. By using different concentrated IAA（0-0.8 rag/L）, some morphological parameters of the root growth of Arabidopsis thaliana were measured. The results showed that there were no significant differences in the length of main root among wild type and the four mutants under the same level of IAA. The main roots growth were inhibited of 5 genotypes along with growth of IAA concentration. The numbers of the lateral root in overexpressed mutants were lower than those in wild type under the same level of IAA, while higher in null mutants. IAA promotes growth of lateral root in Arabidopsis thaliana within the limits of IAA concentration, null mutants （gpa1-1, gpa1-2） are more sensitive compare with the wild type in IAA inducing growth and development of lateral root in Arabidopsis thaliana. The results showed that the heterotrimeric G protein participated in modulating growth and development of root in Arabidopsis thaliana, and the α subunit of heterotrimeric G protein probably acted as a negative regulator for growth of lateral root.