Ginkgo biloba endophyte Rhodococcus sp. FY-5 promotes wound healing in 'Nanguo' Pear by regulating the AsA-GSH cycle and phenylpropane metabolism

Endophytes are a group of microorganisms that exist in various tissues, and organs of plants and are not harmful to plants. In this study, we treated artificially injured 'Nanguo' pear with the endophyte Rhodococcus sp. FY-5 from Ginkgo biloba, and explored the effects of different treatments on the wound healing of 'Nanguo' pear by observing the population dynamics of the bacterial strains at the wound. The results showed that Ginkgo biloba endophyte Rhodococcus sp. FY-5 was able to stabilize the colonization at the fruit wounds, and the 'Nanguo' pear was treated with Ginkgo biloba endophyte Rhodococcus sp. FY-5 had higher activities of phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), and cinnamate 4-hydroxylase (C4H), which promoted the accumulation of phenolic compounds, maintained high antioxidant activity, and activated the ascorbic acid-glutathione cycle to inhibit the mechanical damage-induced reactive oxygen species (ROS). In addition, the treatment of Ginkgo biloba endophyte Rhodococcus sp. FY-5 inhibited the activity of polyphenol oxidase (PPO), which effectively alleviated the browning response of 'Nanguo' pear after mechanical damage. In conclusion, the Ginkgo biloba endophyte Rhodococcus sp. FY-5 could promote the healing of 'Nanguo' pear wounds by regulating the phenylpropane metabolism and the necrotic acid-glutathione cycle in 'Nanguo' pear wounds.