Exogenous Calcium Improved Resistance to by Increasing Autophagy Activity and Salicylic Acid Level in Pear

Pear ring rot, caused by , is one of the most serious diseases in pear. Calcium (Ca) was reported to play a key role in the plant defense response. Here, we found that exogenous calcium could enhance resistance to in pear leaves. Less HO and O but more activated reactive oxygen species scavenge enzymes accumulated in calcium-treated leaves than in HO-treated leaves. Moreover, the increased level of more ascorbic acid-glutathione was maintained by Ca treatment under pathogen infection. The expression of core autophagy-related genes and autophagosome formations were enhanced in Ca-treated leaves. Silencing of in conferred sensitivity to inoculation, which was only slightly recovered by Ca treatment. Moreover, the salicylic acid (SA) level and SA-related gene expression were induced more strongly by in Ca-treated leaves than in HO-treated leaves. Taken together, these results demonstrated that exogenous Ca enhanced resistance to by increasing autophagic activity and SA accumulation. Our findings reveal a new mechanism of Ca in increasing the tolerance of pear to infection.