Preliminary Study On Zinc Finger Protein SRZ1 In The Regulation Of Stress Response In Rice (Oryza Sativa L.)

The abiotic stresses,such as low temperature,drought and high salt,have a great influence on the growth and production of crops.To improve the the adaptability of crop varieties under adverse conditions is the guarantee of high and stable yield of crops.Understand the response mechanism of crops in abiotic stresses and dig stress-related genes are the basic of cultivating resistant crops.Previously,we cloned a rice C2C2 type zinc finger protein gene SRZ1(Stress Repressive Zinc Finger 1)and showed that SRZ1 was highly down-regulated by various abiotic stresses including salt,cold and drought.In the later research on the gene,we found that the root length of SRZ1 RNAi transgenic lines are longer than wild type and SRZ1 overexpression transgenic lines under normal and ABA conditions.Therefore,this paper studied the roles of SRZ1 in the modulation of rice root phenotype of SRZ1 transgenic seedlings,using the method of plant morphology and molecular biology,to do a preliminary study on the molecular mechanism of SRZ1 regulated stress response in rice.Novelties achieved are as follows in this study:1.Tolerance study showed that overexpression of SRZ1 transgenic plants can improve the tolerance to drought,but resistant to salt;on the contrary,SRZ1 RNAi transgenic seedlings can decrease the drought resistance and improve salt tolerance.2.Under normal and ABA,the germination rate of SRZ1 RNAi transgenic seedlings higher than wild type and SRZ1 overexpression transgenic lines,it showed more insensitive to ABA.Under the same conditions,the root length of SRZ1 RNAi transgenic lines are longer than wild type and overexpression transgenic lines.3.Use enzyme linked immunosorbent assay(ELISA),we measured the content of ABA and IAA in the SRZ1 RNAi transgenic seedlings and overexpression transgenic lines.The results showed that the content of IAA in the SRZ1 RNAi plants higher than wild type and SRZ1 overexpression lines,the content of ABA in the SRZ1 overexpression transgenic lines higher than wild type and SRZ1 RNAi plants.The different endogenous hormone content in transgenic plants may be lead to root length changes in the SRZ1 RNAi transgenic seedlings.4.Combined with the reaction mechanism of plant hormone ABA and IAA signal pathway,we detected high expression levels of ABA and IAA related genes in the SRZ1 transgenic plants.The results showed that the expression of ABA related gene OsNCED3 in SRZ1 overexpression transgenic lines,was significantly higher than WT,and ABA related genes,OsPP2C?OsVP1 and OsZEP in the SRZ1 overexpression transgenic lines was lower than WT.The expression of IAA related genes,OsABP1 in the SRZ1 RNAi transgenic lines was significantly higher than the SRZ1 overexpression transgenic lines.5.Transcription factor ABL1 is a negative regulator of ABA signaling in plant.In this study,we used abll mutant to analyse the expression of SRZ1 was related to the ABA signaling pathway.By real-time PCR to test the expression of SRZ1 in abll mutant under salt stress,we found the SRZ1 expression was significantly increased.The expression of SRZ1 was decreased under salt stress inhibited by the mutant of ABL1.Accordingly,ABL1 may be a negative regulator of SRZ1.6.In the rice cDNA yeast library.under salt stress,we use pGBKT7-SRZ1 as the "bait" to screen the protein interacted with SRZ1 by yeast two-hybrid(Y2H),the result showed that Di19 and RubisCO-Large protein interacted with SRZ1 strongly,the interaction was confirmed by BiFC assay.