The accumulation of 2-HOT in infected and senescent leaves is dependent on α-dioxygenase. 2-HOT contents in the wild type and the α-dioxygenase mutants (α-dox1-1, α-dox1-4, α-dox2-2, α-dox2-1, α-dox1-1 α-dox2-2, and α-dox1-4 α-dox2-1) were measured by LC-MS. Leaves at 4 d after C. higginsianum infection (A; infected leaf), senescent leaves (B), and intact leaves were used. Data represent average values ± sd (error bars). Details are provided in Supplemental Figure S6A. FW, Fresh weight.