Loss of function of a DMR6 ortholog in tomato confers broad-spectrum disease resistance
Daniela Paula de Toledo Thomazella, Kyungyong Seong, Rebecca Mackelprang, Douglas Dahlbeck, Yu Geng, Upinder Gill, Tiancong Qi, Julie Pham, P.O. Giuseppe, Clara Youngna Lee, Arturo Ortega, Myeong‐Je Cho, Samuel F. Hutton, Brian J. Staskawicz
Abstract
mutants display enhanced resistance against different classes of pathogens, such as bacteria, oomycete, and fungi. Notably, disease resistance correlates with increased salicylic acid (SA) levels and transcriptional activation of immune responses. Furthermore, we demonstrate that SlDMR6-1 and SlDMR6-2 display SA-5 hydroxylase activity, thus contributing to the elucidation of the enzymatic function of DMR6. We then propose that SlDMR6 duplication in tomato resulted in subsequent subfunctionalization, in which SlDMR6-2 specialized in balancing SA levels in flowers/fruits, while SlDMR6-1 conserved the ability to fine-tune SA levels during pathogen infection of the plant vegetative tissues. Overall, this work not only corroborates a mechanism underlying SA homeostasis in plants, but also presents a promising strategy for engineering broad-spectrum and durable disease resistance in crops.