నైరూప్య

Impact of beta-aminobutyric acid on induced resistance in tomato plants exposed to a combination of abiotic and biotic stress.

Ines Ben Rejeb, Victoria Pastor, Valérie Gravel, Brigitte Mauch-Mani*

A plant’s defensive capacity can be enhanced by treatment with various synthetic and natural compounds capable of improving its immune system and make it more resistant. This is called priming. Primed plants express faster and stronger enhanced defence upon encountering either abiotic or biotic stress. Traditionally, plant stress has been studied by applying a single type of stress such as drought, salinity or infection and analyzing phenotypic and molecular aspects of the resulting plant phenotype. However, this type of analysis is in sharp contrast to natural conditions where plants are simultaneously subjected to a combination of different abiotic and biotic stresses that limit crop yields. Recent evidence shows that a combination of abiotic and biotic stress can have a positive effect on plant performance by reducing the susceptibility to biotic stress. Such an interaction between both types of stress points to crosstalk between their respective signalling pathways. Using the non-protein amino acid β-aminobutyric acid (BABA) to prime tomato plants, we found that BABA-treated plants showed earlier and higher expression of PR1 and PR5 genes following combination of salt stress and infection with Botrytis cinerea compared to non-treated plants exposed to salt. Histochemical analysis revealed that in BABA-treated plants, induced levels of callose deposition and lignin accumulation were higher than in non-treated controls, while the spread of B. cinerea was strongly reduced. A rapid H₂O₂ accumulation detected in BABA-treated plants under combined stress, may have contributed to the observed decrease in the pathogen’s proliferation.