Effect Of Heat Shock Protein Gene OsHSP40 On The Seed Setting Rate Of Rice

Heat Shock Protein is a highly conserved molecular chaperone widely existed in organisms.It plays a very important role in plant growth and development as well as in response to adversity stress.Untile now there are many studies on HSPs in animals,and few reports about plant heat shock protein gene have been reported on plant yield.In this study,we choosed japonica wild type Dongjin as the material.Molecular identification and functional studies of T-DNA insertion homozygous mutant oshsp40obtained from the early stage of laboratory were carried out by molecular biology,transgene technology and cell biology.The main results were as follows:1.The OsHSP40 is distributed on the 2st rice chromosomes,contains 10 exons and 9 introns,and codes 499 amino acids.The predicted protein size is 44279.60,and isoelectric point is 4.96.There are a variety of growing development and stress response elements in promoter region,such as drought induced MYB binding sites MBS.It also contains cis acting elements related to hormone such as MeJA response element CGTCA-motif.Phylogenetic tree analysis showed that the similarity between OsHSP40 protein and sHSP was higher than high molecular heat shock protein.2.Expression pattern revealed that OsHSP40 gene was expressed in different tissue parts of Zhonghua11.This may suggest that OsHSP40 gene makes an impression in the whole growth and development of rice.Expression pattern of OsHSP40 gene exists different under drought,cold and salt.Under cold stress,OsHSP40 gene expression in roots did not change significantly,the expression in leaves and stems were significantly down-regulated.Under drought stress and salt stress,OsHSP40 was significantly up-regulated expressed in stems and leaves.Under drought stress,OsHSP40 was significantly down-regulated expressed in roots,whereas,under drought stress,OsHSP40 was significantly up-regulated expressed in roots.3.Compared with wild type DJ,mutant oshsp40 had shorter plant height,lower seed setting rate,and brown spots on the seed surface.The pollen fertility and viability of the mutant were detected by I₂-KI and FDA.The results showed that the pollen fertility and viability of the mutant were significantly lower than that of the wild type.Pollen germination in vitro showed that the pollen germination rate of the mutant was also decreased,but its floret morphology was not significantly different from that of the wild type.qRT-PCR detection of the genes related to pollen development in the mutant showed that the expression of these genes was significantly down.4.We successfully built the functional complementary vector of OsHSP40.By agrobacterium-mediated method we transformed the reconstructed vector into mutant oshsp40.OsHSP40 transgenic plants with functional complementation were obtained.At present,all T₁ transgenetic seeds have been harvested,which lays a foundation for further study of the biological function of the OsHSP40.