Kloeckera apiculata promotes the healing of potato tubers by rapidly colonizing and inducing phenylpropanoid metabolism and reactive oxygen species metabolism

As a biocontrol yeast, Kloeckera apiculata exhibits excellent control for various postharvest diseases in fruit and vegetables. However, it is still unclear how K. apiculata influences the healing of potato tubers. The effect of K. apiculata treatment on the healing of wounded tuber was investigated by observing the population dynamics of K. apiculata and the formation of the closing layer. Furthermore, this study analyzed the activities and product contents of phenylpropanoid metabolism and reactive oxygen species metabolism at wounds. The results showed that K. apiculata effectively colonized wounds and peaked at 7 d of healing. Tubers treated with K. apiculata exhibited higher key enzyme activities and more production contents of phenylpropanoid metabolism. K. apiculata activated NADPH oxidase and superoxide dismutase, which ascended contents of superoxide anion and hydrogen peroxide. Besides, K. apiculata accelerated suberin polyphenolic and lignin formation and reduced weight loss of wounded tubers and disease index of tubers inoculated with Fusarium sulfureum. Above all, K. apiculata positively affected healing by colonizing and profiling rapidly and inducing phenylpropanoid metabolism and reactive oxygen species metabolism at wounds.