Arbutin Protects Pear Leaves Against Oxidative Stress by Improving Antioxidant Activity

Experimental evidence on the antioxidant role of arbutin, the main phenolic constituent in pear trees, remains limited. In this study, we investigated the effect of exogenous arbutin on the resistance of pear leaves to methyl viologen (MV)-induced oxidative stress. The results showed that arbutin application alleviated chlorophyll degradation and maintained higher photosynthetic efficiency under MV stress. Exogenous arbutin also attenuated the accumulation of malondialdehyde and H₂O₂ and promoted the activity of antioxidant enzymes. Additionally, exogenous arbutin had a mitigating effect on the MV-induced decline in phenolic accumulation and antioxidant capacity, as demonstrated by DPPH and FRAP assays. The expression of phenolic and arbutin biosynthesis-related genes (PAL, CHS, and UGT) significantly increased after MV exposure. Furthermore, arbutin-pretreated pear calli exhibited enhanced tolerance to cold, salt, and abscisic acid (ABA) stresses, characterized by elevated antioxidant enzyme activity and decreased oxidant levels. In tobacco leaves, transient overexpression of UGT enhanced arbutin accumulation and alleviated MV-induced oxidative damage. Collectively, these findings highlight the function of arbutin in controlling oxidative stress responses in pear leaves.