Suprathreshold Water Spray Stimulus Enhances Plant Defenses against Biotic Stresses in Tomato

Mechanical stimuli can affect plant growth, development,
and defenses.
The role of water spray stimulation, as a prevalent mechanical stimulus
in the environment, in crop growth and defense cannot be overlooked.
In this study, the effects of water spray on tomato plant growth and
defense against the chewing herbivore Helicoverpa armigera and necrotrophic fungus Botrytis cinerea were investigated. Suprathreshold water spray stimulus (LS) was
found to enhance tomato plant defenses against pests and pathogens
while concurrently modifying plant architecture. The results of the
phytohormone and chemical metabolite analysis revealed that LS improved
the plant defense response via jasmonic acid (JA) signaling. LS significantly
elevated the level of a pivotal defensive metabolite, chlorogenic
acid, and reduced the emissions of volatile organic compounds (VOCs)
from tomato plants, thereby defending against pest and pathogen attacks.
The most obvious finding to emerge from this study is that LS enhances
tomato plant defenses against biotic stresses, which will pave the
way for further work on the application of mechanical stimuli for
pest management.