Molecular Mechanism Of Adversity Resistance Of Haloxylon Ammodendron Of HaNAC2/3/42 Gene

Haloxylon ammodendron is a typical desert plant,which has developed into an efficient response mechanism to adapt to the changing environment.NAC transcription factors are widely distributed in various terrestrial plants.They not only participate in the growth and development and metabolism of plants,but also play a vital role in the response of plants to various biological or abiotic stresses.Therefore,the analysis of NAC transcription factors in H.ammodendron is of great research value for analyzing the unique regulatory network of stress-resistant molecules in extreme desert environments and exploring the excellent stress-resistant genes.On the basis of previous studies,the functions of HaNAC2/3/42 transcription factors in Haloxylon ammodendron were comprehensively analyzed from three aspects: characterization analysis(binding activity analysis and protein interaction analysis),functional analysis(functional verification of HaNAC42 transgenic Arabidopsis thaliana)and molecular mechanism of stress resistance(transcriptome sequencing of HaNAC2 and HaNAC3 transgenic tobacco).The main conclusions are as follows :(1)Yeast single hybridization was used to verify the core elements that HaNAC3/42 could bind to,and the results showed that HaNAC3/42 could bind to the target element CGT[G/A] in yeast strains.The formation of HaNAC2/3/42 and other HaNACs dimers was analyzed by yeast two-hybrid technology.The results showed that HaNAC42 could not only form homodimers with itself,but also form heterodimers with HaNAC2/3/38 in yeast.In addition,it was also proved that HaNAC2 and HaNAC3 could not form heterodimers in yeast,and HaNAC2 and HaNAC38 could not form heterodimers.(2)The stress resistance function of HaNAC42 over-expressed A.thaliana was verified.The results showed that HaNAC42 gene delayed the germination of A.thaliana seeds and improved the tolerance of A.thaliana at seedling stage under high temperature and salt stress.(3)Transcriptome sequencing was performed on HaNAC2 transgenic tobacco.The results showed that HaNAC2 transgenic tobacco might improve the drought tolerance of plants mainly by participating in phenylpropanoid biosynthesis and carbon metabolism in roots.HaNAC2 transgenic tobacco leaves might resist high temperature by positively regulating starch sucrose metabolism and phenylpropanoid biosynthesis.(4)The transcriptome sequencing of HaNAC3 transgenic tobacco showed that the HaNAC3 gene was mainly resistant to drought stress through root metabolism of tobacco,mainly through phenylpropanoid biosynthesis and glutathione metabolism.HaNAC3 gene resists high temperature in tobacco leaves by up-regulating plant hormone signal transduction and glutathione metabolism.