Comparative transcriptomic and physiological analyses reveal the key role of abscisic acid in hydrangea macrophylla responding to Corynespora cassiicola

Bigleaf hydrangea (Hydrangea macrophylla) is a widely cultivated ornamental plant species. Leaf spot disease, caused by Corynespora cassiicola, poses a significant threat to the ornamental quality and economic value of hydrangeas. However, the disease resistance breeding of hydrangea is limited due to the lacking of resistant varieties and genes.