Brassinosteroids: Under biotic stress

Abstract

Brassinosteroids are the steroidal plant hormones, key regulators of growth and metabolism in metabolically active tissues. Their interplay ensures either the accelerated growth or differentiation in meristematic tissues or induces the defense responses in biotically challenged tissues, stopping the growth responses in concentration dependent manner. A rationale of highly active growth regulators and classical phytohormones, based on external cues and endogenous developmental program, ascertains the fate of localized tissue for the sake of whole plant, may induce hypersensitive response based PCD, activating LAR and/or SAR. A shift of growth metabolism towards defense strategies is evidenced in several Arabidopsis and other BR mutants suggesting their antagonistic role. However, specific interaction of BRs with well known other phytohormones in suppressing the growth responses under biotic stress, have been tried to underline in the present survey.