Parthenocarpy Induced Fluctuations in Pungency and Expression of Capsaicinoid Biosynthesis Genes in a Japanese Pungency-variable Sweet Chili Pepper ‘Shishito’ (<i>Capsicum annuum</i>)

The pungency-variable sweet chili pepper ‘Shishito’ (Capsicum annuum) is widely cultivated in Japan. While generally used as a vegetable because of its relatively low pungency, it sometimes exhibits high pungency depending on cultivation conditions. Although the occurrence pungent fruits problem retail distribution and utilization, responsible mechanism largely unknown. As one approach to clarify mechanism, we focused effects parthenocarpy (resulting seedless fruit) traits fruits. In present study, artificial parthenocarpic were prepared by treatment with 2,4-dichlorophenoxyacetic acid (2,4-D), level was investigated quantification capsaicinoids, components for pungency. For comparison, two controls used: naturally pollinated 2,4-D-treated which exposed 2,4-D without parthenocarpy. results indicated that capsaicinoid content tended be higher compared controls. This suggests alterations associated Further, these relationships assessed using molecular method, gene expression analysis qRT-PCR conducted 16 biosynthesis genes. showed eight genes (Pun1, pAMT, KAS, CaMYB31, BCAT, CaKR1, ACL, FAT) exhibited parthenocarpy-specific expression, suggesting influence levels novel report carefully parthenocarpy-dependent changes pepper. We anticipate data will add horticultural knowledge help control during cultivation.