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

The wild type Arabidopsis thaliana and its mutants in which heterotrimeric G protein α subunit gene GPA1 was null(gpα11,gpα1-2) or overexpressed(wGα,cGα) were used as main materials.By using different concentrated IAA(0~0.8 mg/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(gpα1-1,gpα1-2) 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.