Ethylene-mediated resistance to bacterial canker in kiwifruit is suppressed by cool temperature

Abstract

Ambient temperature affects the occurrence and prevalence of plant disease. Most bacterial diseases are damaging at high temperatures. However, kiwifruit bacterial canker caused by pv. () has been found to be prevalent at relatively cool temperatures, and it is unclear how ambient temperature affects the development of kiwifruit bacterial canker. In this study, basal resistance to was suppressed in kiwifruit at cool growth temperature (16 °C) compared with at normal temperature (24 °C). In addition, RNA sequence analysis and ethylene content assessment indicated that ethylene modulated kiwifruit resistance to at normal growth temperature and that cool temperature inhibited ethylene accumulation and -induced activation of the ethylene signaling pathway in kiwifruit. Virus-mediated silencing of the kiwifruit ethylene signaling gene suppressed kiwifruit resistance to at normal growth temperature. Exogenous application of ethylene inhibitor 1-methylcyclopropene eliminated the difference in kiwifruit resistance to at 16 and 24 °C. Exogenous application of ethylene analogues ethephon induced resistance to in kiwifruit. In conclusion, cool temperatures impair basal resistance to by reducing the activation of ethylene biosynthesis and signaling in kiwifruit. The results provide clues for new strategies to control plant diseases in a context of global environmental change.