Genetic variability of Pun1 gene (capsaicin synthase) in pungent cultivars of capsicum annuum of northern Mexico

Abstract

Background: Capsaicinoids are exclusive of the genus Capsicum and are responsible for fruit pungency. The genetic basis of pungency is not yet fully understood, although several candidate genes have been analyzed including the Pungent gene (Pun1). Objective: The main aim of this study was to identify the Punl in some pungent samples of Capsicum annuum of Northern Mexico adapted to conditions of high temperature and analyze the variability of polymorphisms in the gene. Methodology: The coding sequence of the Punl gene was analyzed by Polymerase Chain Reaction and Restriction Fragment Length. Results: The Punl gene showed highly variable patterns: the variable regions were sequenced, and we found 19 single nucleotide polymorphisms in the first exon and 7 in the intron. some polymorphisms generated amino acid changes: while that of Chiltepin cultivar showed more than one sequence. Implications: The protein homology model suggests that these polymorphisms could affect their functionality. Conclusion: All the pungent cultivars of Mexican C. annuum analyzed were positive to Pun1 gene and have a high variety of polymorphisms, this study provides evidence of the high variability that exists in the Pun1 gene responsible for pungency and could allow the selection of pungent variants to obtain a greater quantity of capsaicinoids for different applications.