A Raf-like kinase is required for smoke-induced seed dormancy in <i>Arabidopsis thaliana</i>

Abstract

Plants sense and integrate diverse stimuli to determine the timing for germination. A smoke compound, 3,4,5-trimethylfuran-2(<i>5H</i>)-one (trimethylbutenolide, TMB), has been identified to inhibit the seed germination of higher plants. To understand the mode of action, we examined various physiological and molecular aspects of the TMB-dependent inhibition of seed germination in <i>Arabidopsis thaliana</i> The results indicated that the effect of TMB is due to the enhanced physiological dormancy, which is modulated by other dormancy regulatory cues such as after-ripening, stratification, and ABA/GA signaling. In addition, gene expression profiling showed that TMB caused genome-wide transcriptional changes, altering the expression of a series of dormancy-related genes. Based on the TMB-responsive physiological contexts in <i>Arabidopsis</i>, we performed mutant screening to isolate genetic components that underpin the TMB-induced seed dormancy. As a result, the <i>TMB-RESISTANT1</i> (<i>TES1</i>) gene in <i>Arabidopsis</i>, encoding a B2 group Raf-like kinase, was identified. Phenotypic analysis of the <i>tes1</i> mutant implicated that <i>TES1</i> has a critical role in the TMB-responsive gene expression and the inhibition of seed germination. Taken together, we propose that plants have been equipped with a TMB sensory pathway through which the TMB induces the seed dormancy in a TES1-dependent way.