Root zone warming represses foliar diseases in tomato by inducing
Plants employ systemic induced resistance as part of their defense
arsenal against pathogens. In recent years, the application of mild
heating has been found to induce resistance against several pathogens.
In the present study, we investigated the effect of root zone warming
(RZW) in promoting tomato resistance against the necrotrophic fungus
Botrytis cinerea (Bc), the hemibiotrophic bacterium Xanthomonas
campestris pv. vesicatoria (Xcv) and the biotrophic fungus Oidium
neolycopersici (On). We demonstrate that RZW enhanced tomato resistance
to Bc, On and Xcv, through a process that is dependent on salicylic
acid. RZW induced tomato immunity, resulting in increased defense gene
expression, reactive oxygen species (ROS), and ethylene output when
plants were challenged, even in the absence of pathogens. Overall, the
results provide novel insights into the underlying mechanisms of warming
induced immune responses against phytopathogens with different
lifestyles in tomato.