Function Verification Of Rice Root Gravitropism Regulatory Protein OsGLS1

Root plays an important role in whole life of plant. Plant roots have great effect on plant anchoring, water and nutrients uptaking as well as normal physiological processes. Gravitropism of plant root is one of the important factors determining the spatial pattern of root growth.Therefore, study on the molecular mechanisms and biochemical networks of root gravitropism have theoretical and practical significance for guiding the genetic improvement of rice. Based on the rice gravitropic defect mutants, glsl, this study focuses on the function analysis of GLS1 protein. We found that GLS1 protein has ubiquitin E3 ligase activity in vitro, and further we found that the RING finger domain amino acid motif is responsible for the ubiquitin E3 ligase activity. Phylogenetic analysis showed that WAV3 is the homologous gene of GLSl in Arabidopsis. In the WAV3 gene family, there are three members in Arabidopsis controlling root gravitropism, but only one homolog in rice. Further study to transform the OsGLS1 to Arabidopsis wav3 mutant indicated that, GLS1 CDS transgenetic lines(T2) are able to relieve its phenotype to some extent. This indicates that GLS1 and WAV3 have similar function in controlling gravitropism in rice and Arabidopsis.