Effect and Mechanism of Patchouli Alcohol for the Management of Postharvest Green Pepper Fruit Rot Caused by Alternaria alternata

Green pepper, a commonly cultivated vegetable, often suffers from fruit rot caused by Alternaria alternata, which reduces its quality and shelf life. In this study, the antifungal activity and mechanism of patchouli alcohol (PA), which was isolated from Pogostemon cablin essential oil, against A. alternata during the storage of green peppers, were investigated. PA effectively inhibited the growth of A. alternata in vitro and in vivo assays, reduced lesion areas, and extended the storage life of green peppers. Scanning and transmission electron microscopy revealed that PA induced significant morphological deformations in A. alternata hyphae, inhibited spore germination, and disrupted the cellular structures. Transcriptomic, proteomic, and physiological analyses suggested that PA impaired cell membrane synthesis and function, disrupted mitochondrial activity, and induced oxidative stress, resulting in cellular dysfunction and apoptosis. These actions significantly suppressed A. alternata growth, ultimately prolonging the shelf life of the green peppers. This study provides the potential use of PA for green pepper preservation.