Root zone warming represses foliar diseases in tomato by inducing systemic immunity

Area of Science:

• Plant pathology
• Plant immunity
• Molecular plant-microbe interactions

Background:

• Plants possess systemic-induced resistance mechanisms against pathogens.
• Mild heating has emerged as a method to induce plant resistance.
• Understanding warming-induced immunity is crucial for crop protection.

Purpose of the Study:

• To investigate the effect of root zone warming (RZW) on tomato resistance.
• To determine RZW's impact against diverse pathogens: Botrytis cinerea, Xanthomonas campestris pv. vesicatoria, and Oidium neolycopersici.
• To elucidate the molecular mechanisms underlying RZW-induced immunity.

Main Methods:

• Application of root zone warming (RZW) to tomato plants.
• Challenging plants with three distinct phytopathogens: Botrytis cinerea (Bc), Xanthomonas campestris pv. vesicatoria (Xcv), and Oidium neolycopersici (On).
• Analysis of defense-related gene expression, reactive oxygen species (ROS) production, and ethylene output.

Main Results:

• RZW significantly enhanced tomato resistance against Bc, On, and Xcv.
• The induced resistance was dependent on salicylic acid and ethylene signaling pathways.
• RZW led to elevated defense gene expression, ROS, and ethylene levels upon pathogen challenge, even without pathogens present.

Conclusions:

• Root zone warming is an effective strategy for bolstering tomato plant immunity.
• Salicylic acid and ethylene are key mediators of warming-induced resistance in tomato.
• RZW primes tomato plants, enhancing their preparedness against diverse pathogens.