Effects of Perillaldehyde and Polyamines on Defense Mechanisms of Sweet Potatoes against <i>Ceratocystis fimbriata</i>

Sweet potato (<i>Ipomoea batatas</i>) serves as a significant food and economic crop worldwide. However, its production and safety are jeopardized by black rot, a disease caused by <i>Ceratocystis fimbriata</i>. Although polyamines (PAs) are common biological growth factors, their function in the storage of fruits and vegetables remains poorly understood. This study examines the physiological roles of both exogenous and endogenous PAs in <i>C. fimbriata</i>, particularly their metabolism via gene knockout techniques. Additionally, we assessed how exogenous PAs affect sweet potato storage resistance. Our findings reveal that PAs are crucial in managing oxidative and cell wall stress in <i>C. fimbriata</i>. At high concentrations, PAs displayed cytotoxic effects through the upregulation of nitric oxide synthase (<i>TAH18</i>). Furthermore, exogenous PAs significantly enhanced the defense mechanisms of sweet potatoes during storage. The concurrent use of perillaldehyde (PAE), a natural antibacterial compound, additionally decreased the incidence of black rot in sweet potatoes. This study provides a novel strategy and theoretical basis for the prevention and control of fungal diseases in stored fruits and vegetables.