Expression Characteristics And Preliminary Function Identification Of Rice OsRac5Gene

Rop is a wide kind of small G proteins, which involved in multiple physiological processes of higherplant. Rop plays molecular switch in almost all biological process such as polarity growth, organdevelopment, immune response and environment signals, and mediated downstream signal transduction.Therefore, it is helpful to understanding the functional mechanism of plant genes how to regulate thedevelopment process, biotic and abiotic steress, hormone response with the clear function of Ropgene.OsRac5gene was isolated from the pistil and stamen of riceyoung panicles, which was belongs tothe Rop protein family. According to previous studies, the OsRac5gene may be involved in the regulationof rice photoperiod fertility conversion associated signal transduction, its function involving fertilityexpression of rice. But its expression characteristics and the exact function has not been reported.To better understand the biological function of the OsRac5gene, this paper using real-timequantitative RCR technical analysis of the gene expression of rice different tissues in three typical stages ofgrowth and development. The results show OsRac5was constitutively expressed in rice roots, stems, andleaves at different developmental stages, especially with highest abundance in young panicle, it turned outthat OsRac5related to a kind of biological process such as rice growth and development, and most likelyclosely related with the rice floral organ development.This paper also detected its expression characteristics under the treatment of six kinds of planthormones like ABA, IAA, SA,6-BA, GA, BR, The results showed that in rice seedling stage OsRac5wasconstitutively expressed under the treatment of six kinds of plant hormones, and ABA, GA, and6-BA cansignificantly up-regulate its expression, especially with highest abundance under treatment of ABA and GA,while IAA lead to the opposite effect. The results illustrate that OsRac5gene maybe was involved in mosthormone responses physiological processes.This paper also detected its expression characteristics under the treatment of three common kinds ofabiotic stress, such as drought, cold and high salt. The results show that drought, salt and cold also inducedexpression of OsRac5gene with different expression patterns. Compared to the cold, OsRac5is moresensitive to drought stress response especially in upside-plant. But with the treatment of high salt, expression of OsRac5is gradually up-regulated in upside-plant, and down-regulated on24h. Compared tothe upside-plant, its expression tendency was contrary before10h in root, but its expression wassignificantly increased on24h. The above results illustrate that OsRac5gene maybe was involved in moststress resistance physiological processes.In order to further understanding the biological functional mechanism of OsRac5, in this study usedAgrobacterium-mediated manner to introduce1300-MD plant over-expression vector (constructed bylaboratory early stage) into Arabidopsis thalianain florescence, and screen its transgenic plants. Nowwe’ve got the F2generation of transgenic plants, PCR was applied to detect the target gene fragment inline with expectations, in order to further detect overexpression of activated OsRac5effect to Arabidopsisthaliana growth and development.In the same time, the RNA interference vectors of OsRac5, pAND-OsRac5plasmid was constructedby DNA recombination, and this paper use aboved-mentioned manner to introduce pAND-OsRac5vectors and1300-MD and1300-D plant overexpression vectors into rice respectively, now the T0generation of transgenic plants screening progress is ongoing.This study systematically analyzed the expression characteristics of OsRac5, two classic transgenicsystem to carry out functional identification of OsRac5, in order to obtain transgenic plants, analyze thephenotype of gene overexpression and silencing rice transgenic plants, to lay the foundation for studyingphysiological detection and molecular identification, it will helpful for a comprehensive analysis ofOsRac5with biological function development, abiotic stress and hormone response in rice.