Functional Study Of Arabidopsis CNGC2 And CNGC4 Genes In Thermotolerance And Disease Resistance

Plants growth is modulated by many environmental factors including temperature and microbial pathogen.Plants have formed many defense mechanisms to cope with pathogens and temperature stresses.Some CNGCs(Cyclic Nucleotide-Gated Ion Channels)that are non-selective cation channels have been shown to affect plant disease resistance and heat tolerance.Early studies have found that CNGC2 and CNGC4 are negative regulators of disease resistance in Arabidopsis,and CNGC2 is a negative regulator of thermotolerance.In order to determine the relationship between the roles of CNGC2 and CNGC4 in disease resistance and thermotolerance,we used the loss of function of PAD4,a key regulator of disease resistance,to explore the interaction of disease resistance and heat tolerance function of CNGC2 and CNGC4.We obtained the mutants cngc2 cngc4,cngc2 pad4,cngc4 pad4 and cngc2 cngc4 pad4 by hybridization.As previously reported,CNGC2 and CNGC4 are negative regulators of disease resistance in Arabidopsis.DAB(3,3'-Diaminobenzidine)and Trypan Blue staining results indicated that CNGC2 and CNGC4 affect H2O2 accumulation and cell death.Mutation in PAD4 reduces disease resistance to bacterial pathogen Pst DC3000 in cngc2 and cngc4.The cngc2 and cngc4 mutants have a dwarfing phenotype at the seedling stage compared to the wild type,and the flowering time is significantly delayed.Deletion of PAD4 partially restores the dwarf phenotypes of cngc2 and cngc4,but it does not affect at the flowering time phenotype at 22?.The PAD4 mutation does not affect the flowering phenotypes of cngc2 and cngc4 at 28? either.In addition,we found that the cngc2,cngc4 and cngc2 cngc4 mutants have enhanced basal and acquired heat tolerance.In addition,mutations in CNGC2 and CNGC4 affected the stomatal aperture under heat stress.Preliminary results showed that PAD4 affected the thermotolerance of cngc2 and cngc4,therefore the heat resistance of cngc2 and cngc4 might be dependent on enhanced disease resistance,and this interaction will be further studied.