The Functional Mechanism Of Rice Heat Shock Transcription Factor OsHsf18 On Regulating Plant Resistance Against Biotic And Abiotic Stresses

Rice is one of the important food crops for human survival,but its growing environment is deteriorating,such as subjected to biotic and abiotic stresses.During long-term evolution,rice has produced a series of mechanisms that respond to stress,and the heat-shocked transcription factor in rice is located at the end of the stress-responsive gene expression signal transduction chain and can specifically bind highly conserved heat shock element(HSE)(5'-nGAAn-3'),in combination with other transcription factor to forms a transcription complex to regulate the expression of heat shock protein(HSP)and stress-related genes.The main body of this thesis is divided into three parts.One is to analyze the function of OsHsf18 in resisting abiotic stress;the second is to analyze the role of OsHsf18 in disease resistance;the other is to perform CHIP-Seq and RNA-Seq on OsHsf18 leaves after high temperature treatment.The main results are as follows:1?Identify and obtain stable inherited OsHsf18-OX/RNAi transgenic lines.2?After the OsHsf18-OX/RNAi strain and the wild type Nipponbare treated with high temperature,drought,high salinity and low temperature,the results showed that the OsHsf18 gene could be induced by the above stresses,and OsHsf18-OX up-regulates rice tolerance.3?After Inoculating of the rice blast fungus,the expression levels of stress-resistance related genes PR1 a,PR10,and WRKY45 in OsHsf18-OX after inoculation were significantly lower than those in the wild type,and the range of lesions was larger than the other two materials,However,the OsHsf18-RNAi seedlings had the lowest incidence of leaves,the expression levels of stress-resistance related genes PR1 a,PR10,and WRKY45 in OsHsf18-RNAi after inoculation were higher than those in the wild type.4?After Inoculating of PXO-99.The results showed that the expression levels of PR2 and WRKY45 were significantly higher in OsHsf18-OX than in the wild type,and the lesion length was minimal.OsHsf18-RNAi seedlings had the highest degree of disease,and the expression levels of PR2 and WRKY45 were lower than wild type,and the bacterial count on their diseased leaves also confirmed this result.5?The OsHsf18-OX material was treated at a high temperature of 42°C and the untreated OsHsf18-OX material was used as a control for CHIP-Seq and RNA-Seq.The results showed that 6024 up-regulated differentially expressed genes were obtained from RNA-Seq,and 6927 down-regulated differentially expressed genes were obtained,CHIP-Seq obtained 4447 up-regulated Peak related genes,2243 down-regulated Peak related genes,combined Pathway significant enrichment analysis of both,rice heat stress response genes are mainly involved in Plant-pathogen interaction,Plant hormone signal transduction,Glyoxylate and dicarboxylate metabolism,Ascorbate and aldarate metabolism and so on.In order to verify the accuracy of the sequencing results,we randomly selected some genes by RT-qPCR for validation.The results show that genes in above pathways were involved in OsHsf18 regulation on rice resistance to biotic and abiotic stresses.