Capsaicinoids production and accumulation in epidermal cells on the internal side of the fruit pericarp in ‘Bhut Jolokia’ (Capsicum chinense)

Abstract

Capsaicinoids are pungent components that are produced only in the genus Capsicum. These functional compounds are produced in chili pepper fruits and have health benefits for humans. A high capsaicinoid level is one of the major parameters determining the commercial quality and health-promoting properties of chili peppers. Several reports have indicated that capsaicinoids are produced in the interlocular septum of chili pepper fruits. Microscopic analyses show that there are morphological changes in epidermal cells in the interlocular septum during the capsaicinoid-biosynthesis stages of fruit development. Epidermal cells containing capsaicinoids in the interlocular septum had an elongated shape. Recently, it was reported that capsaicinoids and transcripts of genes encoding enzymes involved in capsaicinoid biosynthesis were present in the fruit pericarp of extremely pungent chili cultivars. However, the morphological changes in epidermal cells in pericarp tissue had not been reported. In this study, microscopic analyses of the fruit of Capsicum chinense cv. Bhut Jolokia, an extremely pungent chili pepper variety, revealed elongated epidermal cells secreting capsaicinoids on the inside surface of the pericarp.