Chilling stress severely restricts tomato cultivation and productiveness, but the mechanisms by which a single regulator integrates photosynthetic effectivity, developmental development, and chilling tolerance stay to be elucidated. Right here, we characterised SlBBX19, a chilling-inducible B-box transcription think about tomato (Solanum lycopersicum). SlBBX19 is nucleus-localized, features as a adverse regulator of vegetative progress and photosynthetic capability underneath regular situations, whereas concurrently selling fruit ripening and suppressing inflorescence branching. Underneath chilling stress, SlBBX19 acts as a adverse regulator of chilling tolerance: overexpression exacerbates reactive oxygen species (ROS) accumulation, membrane harm, and suppresses COR pathway activation, whereas knockout strains exhibit enhanced chilling resistance. Transcriptomic and molecular analyses reveal that SlBBX19 immediately binds to G-box parts within the promoters of light-harvesting chlorophyll a/b-binding genes SlLhcb2.2 and SlLhca4.1 to repress their transcription. Virus-induced gene silencing of those targets recapitulated the overexpression phenotypes, confirming that SlBBX19 compromises photosynthetic effectivity and chilling tolerance primarily by SlLhc downregulation. Collectively, our findings set up SlBBX19 as a key integrator of growth and environmental acclimation, revealing a novel regulatory module that hyperlinks photosynthetic antenna dynamics to chilling stress adaptation. This work could present a promising genetic goal for engineering chilling-tolerant and physiologically optimized tomato varieties.
Key phrases:
BBX transcription issue; chilling tolerance; fruit ripening; gentle‐harvesting chlorophyll a/b‐binding; photosynthesis; tomato.
