title: A low-pungency S3212 genotype of Capsicum frutescens caused by a mutation in the putative aminotransferase (p-AMT) gene.
abstract: The purpose of this study was to identify the genetic mechanism underlying capsinoid biosynthesis in S3212, a low-pungency genotype of Capsicum frutescens. Screening of C. frutescens accessions for capsaicinoid and capsiate contents by high-performance liquid chromatography revealed that low-pungency S3212 contained high levels of capsiate but no capsaicin. Comparison of DNA coding sequences of pungent (T1 and Bird Eye) and low-pungency (S3212) genotypes uncovered a significant 12-bp deletion mutation in exon 7 of the p-AMT gene of S3212. In addition, p-AMT gene transcript levels in placental tissue were positively correlated with the degree of pungency. S3212, the low-pungency genotype, exhibited no significant p-AMT transcript levels, whereas T1, one of the pungent genotypes, displayed high transcript levels of this gene. We therefore conclude that the deletion mutation in the p-AMT gene is related to the loss of pungency in placental tissue and has given rise to the low-pungency S3212 C. frutescens genotype. C. frutescens S3212 represents a good natural source of capsinoids. Finally, our basic characterization of the uncovered p-AMT gene mutation should contribute to future studies of capsinoid biosynthesis in Capsicum.
authors.affiliation: Graduate School of Agriculture, Shinshu University, 8304 Minami-minowa, Kami-ina, Nagano, 399-4598, Japan.
authors.forename: Young-Jun
authors.initials: YJ
authors.lastname: Park
authors.affiliation: Genetic Resources Center, National Insitute of Agrobiological Sciences, 2-1-2, Tsukuba, Ibaraki, 305-8602, Japan.
authors.forename: Tomotaro
authors.initials: T
authors.lastname: Nishikawa
authors.affiliation: Graduate School of Agriculture, Shinshu University, 8304 Minami-minowa, Kami-ina, Nagano, 399-4598, Japan.
authors.forename: Mineo
authors.initials: M
authors.lastname: Minami
authors.affiliation: Graduate School of Agriculture, Shinshu University, 8304 Minami-minowa, Kami-ina, Nagano, 399-4598, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nemoto
authors.affiliation: Graduate School of Agriculture, Shinshu University, 8304 Minami-minowa, Kami-ina, Nagano, 399-4598, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Iwasaki
authors.affiliation: Graduate School of Agriculture, Shinshu University, 8304 Minami-minowa, Kami-ina, Nagano, 399-4598, Japan. matuken@shinshu-u.ac.jp.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Matsushima
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D002212:Capsicum / Q000201:enzymology / Q000235:genetics*; D017343:Genes, Plant; D005838:Genotype; D008969:Molecular Sequence Data; D009154:Mutation; D060888:Real-Time Polymerase Chain Reaction; D000637:Transaminases / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D000637:Transaminases
keywords: Capsicum frutescens; Capsinoid; Deletion mutation; Low-pungency; Putative aminotransferase