The Cloning And Function Characterization Of Transcription Factor CaNAC72of Capsicum Annuum

Pepper (Capsicum annuum L.) is an important Solanaceae vegetable. In nature,plants are often exposed to various biotic and abiotic stresses, pepper production havebeen seriously affected. NAC(NAM, ATAF1/2, CUC2)transcription factors are afamily of genes specific to plants that have been shown to be involved in regulatingdiverse processes, such as development, senescence and stress responses. Thus,isolation and functional analysis of pepper NAC genes show important significance toelucidate the defense mechanism of pepper and promote pepper genetic improvement.In this paper, full-length cDNA of CaNAC72, a gene encoded NAC transcriptionfactors was isolated from the normalized cDNA library and the subcellularlocalization, expression and function were studied. The main results were asfollowings:1. Full-length cDNA clone encoded CaNAC72was isolated from peppernormalized cDNA. Its ORF encodes a protein of350amino acids and the proteinscontained highly conserved N-terminal NAC domains that can bind both DNA andother proteins, which was accompanied by diverse C-terminal domains. We found itto share70%amino acid sequence identity with the AtNAC072of Arabidopsis andbelonged to groupIII SNAC (stress-related NAC genes), it was named CaNAC72.2. Transient expression analysis of35S::CaNAC72-GFP fusion protein in theepidermal cells of onion suggested that CaNAC72protein was localized in thenucleus.3. Yeast transformed assay suggested that the transactivation region ofCaNAC72was located in the C-terminals.4. Transient expression analysis in onion epidermal cells suggested thatCaNAC72proteins could bind to the NACRS cis-acting element to activate the GUSgene expression.5. Real time PCR analysis suggested that The expression of CaNAC72wasinduced by hormones (SA, JA, ET and ABA), dehydration, high salinity, cold, heatand Ralstonia solanacearum inoculation. 6. The phenotypes analysis of CaNAC72-overexpressed T1transgenic line underbiotic and abiotic stresses suggested that the transgenic plants overexpressingCaNAC72were hypersensitive to Ralstonia solanacearum and confers high salinitytolerance.In conclusion, the CaNAC72was a new member of NAC transcription factorfamily in pepper. Our study showed that CaNAC72might be involved in pepperresponse to high salinity and Ralstonia solanacearum stresses.