Abstract
Pepper (Capsicum annuum L.) is an economically important crop with added nutritional value. Production of capsaicin is an important quantitative trait with high environmental variance, so the development of markers regulating capsaicinoid accumulation is important for pepper breeding programs. In this study, we performed association mapping at the gene level to identify single nucleotide polymorphisms (SNPs) associated with capsaicin pathway metabolites in a diverse Capsicum annuum collection during two seasons. The genes Pun1, CCR, KAS and HCT were sequenced and matched with the whole-genome sequence draft of pepper to identify SNP locations and for further characterization. The identified SNPs for each gene underwent candidate gene association mapping. Association mapping results revealed Pun1 as a key regulator of major metabolites in the capsaicin pathway mainly affecting capsaicinoids and precursors for acyl moieties of capsaicinoids. Six different SNPs in the promoter sequence of Pun1 were found associated with capsaicin in plants from both seasons. Our results support that CCR is an important control point for the flux of p-coumaric acid to specific biosynthesis pathways. KAS was found to regulate the major precursors for acyl moieties of capsaicinoids and may play a key role in capsaicinoid production. Candidate gene association mapping of Pun1 suggested that the accumulation of capsaicinoids depends on the expression of Pun1, as revealed by the most important associated SNPs found in the promoter region of Pun1.
Highlights
Pepper (Capsicum annuum L.) is a crop of major agricultural and economic importance
principal component analysis (PCA) with normalized concentration values for various metabolites (Table S3) obtained by gas chromatography coupled with mass spectrometry (GC/MS) and highperformance liquid chromatography (HPLC) revealed nonpungent peppers with trace amounts of capsaicin and those with low pungency and a few moderately pungent accessions remaining on the negative side of the Y-axis, with only moderate, high- and very high-pungent accessions located on the positive side of the Yaxis (Fig. 1)
In season 2, all peppers showed a significant decrease in capsaicin, which indicated a high degree of environmental variance
Summary
Pepper (Capsicum annuum L.) is a crop of major agricultural and economic importance. It is known for its pungency, rich flavor, and nutritional value. Pepper contributes a range of beneficial metabolites, such as carotenoids, flavonoid glycosides and vitamins, to the human diet [2]. The most unique metabolites are the alkaloids denominated by capsaicinoids, which make peppers pungent and are produced mainly in the placenta of the fruits [3]. The most important pharmaceutical role of capsaicin is in pain perception. The transient receptor potential of vanilloid type 1 receptor (TRPV1) is activated by capsaicin in mammalian nociceptor cells, triggering inflammation and pain responses [7,8]. Prolonged exposure to capsaicin numbs the TRPV1 over time, for long-term pain relief
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
