Functional Study Of AtWRKY50 And AtWRKY51 Genes In Response To Abiotic Stresses

WRKY transcription factors are one of the large transcription families in higher plants,and there are a number of reports that WRKY transcription factors involved in biotic and abiotic stresses.WRKY transcription factors often regulate the stress tolerance by JA,SA,ABA and other signaling pathways in plant.AtWRKY50 and AtWRKY51 have higher homology with a Heat Shock protein in rice.So the function study of At WRKY 50 and At WRKY 51 will lay the foundation for the study of rice Heat Shock protein,and broaden the theory in abiotic stress breeding of rice and other crops.To study the function of AtWRKY50,we screened the T-DNA insertion mutants,wrky50,and constructed the overexpression line.The results illustrated that the expression of AtWRKY50 was affected by JA,SA and ethylene in rosette,at the same time high temperatures and drought also affected the expression.Under JA treatment,the germination rate and root length of wrky50 were significantly smaller or shorter than wild-type,which indicating that the gene may be involved in JA biosynthesis or signaling pathway.Under ABA treatment,the germination rate of wrky50 was significantly less than the wild-type,which indicating that the gene may be involved in ABA synthesis or signal transduction pathways.Under the high temperature and drought stress,the germination rate of wrky50 was significantly less than the wild type,overexpression lines were more than wild type,which indicating AtWRKY50 can enhance the tolerance of heat and drought stress in seedling stage.We obtained the mutant,w51,and the overexpression lines as the study-method of WRKY50.The results illustrated that the expression of AtWRKY51 was affected by JA,SA and ethylene in rosette,simultaneously high temperatures and drought also affected the expression.Under ABA treatment,the germination rate of wrky51 was significantly less than the wild-type,which indicating that the gene may be involved in ABA synthesis or signal transduction pathways.Under the salt and drought stresses,the germination rates of wrky51 were significantly less than the wild type,which indicating AtWRKY51 can enhance the tolerance of salt and drought stress in seedling stage.We also found that,the leaves of wrky51 were longer than wild-type,whereas the leaves of overexpression lines were less than wild-type,so AtWRKY51 reduced elongation of the blade.To study whether AtWRKY51 and AtWRKY50 have functional redundancy,we obtained the double mutant wrky50/wrky51 by Hybriding.Germination tests showed that the germination rates of double mutant were significantly higher than the wild type under the ABA,drought and heat treatment.