Salt tolerance analysis of CaNAC36 in peppers

Abstract [Objective] Pepper is the largest vegetable crop planted in China. With the land salinization becoming more and more serious, it is urgent to accelerate the functional study of key genes related to pepper salt tolerance. It is of great significance to strengthen the study of mechanisms underlying salt tolerance in peper to promote sustainable development of the pepper industry. [Methods] In the early stage of research, CaNAC36, a NAC transcription factor family gene related to salt stress response in peppers, was discovered. Based on this, the full-length gDNA and cDNA sequences of CaNAC36 were cloned using salttolerant pepper accession PI201224 and salt-sensitive pepper accession PI438643. The expression of CaNAC36 and its interacting genes in different tissues under salt stress was quantitatively analyzed by fluorescence, and the potential relationship between CaNAC36 and its interacting genes was further explored by bioinformatics analysis. [Results] The gDNA and cDNA sequence homology of CaNAC36 in salt-tolerant and salt-sensitive materials were 99.86% and 100%, respectively. CaNAC36 showed an up-expression in roots and stems in the salt-tolerant pepper, and a down-expression in roots and leaves in the salt-sensitive peper. Throgh analyzing the annotation information of 48 genes that may interact with CaNAC36, it was found that 14 genes were belonging to transmembrane proteins, transporter proteins, water porins, chloride channel proteins, detoxifying proteins, and other genes, which may have functional interaction with CaNAC36. Further analysis revealed that PI201224 and PI438643 exhibited significant differences in the expression of five related genes, inclding Capana08g002748, Capana00g004514, Capana09g000275, Capana07g001450, Capana02g001031, at different time points and tissues under salt stress. Meanwhile, the promoter region of CaNAC36 and five associated genes was found to contain a large number of stressrelated cis-acting elements. [Conclusion] CaNAC36 was an important regulatory gene in pepper in response to salt stress, and might interact with other genes to improve salt tolerance.