Awakening buds: Navigating tomato axillary bud dormancy from the BRC1 hub

Samenvatting (Engelstalig)

Plants undergo continuous growth through their
main shoot, and specific signals in this growth process trigger the outgrowth
of axillary buds. In indeterminate tomatoes, these axillary buds compete for
energy with fruit production. Central to this axillary bud regulation is TCP
transcription factor (TF) BRANCHED1 (BRC1) playing a key role in suppressing
bud outgrowth. Both endogenous and exogenous signals are integrated upstream of
BRC1 and depending on the signals BRC1 expression is differentially modulated
for either dormancy or outgrowth. In my project, I investigate the
transcriptional regulation of BRC1 by employing phylogenetic
footprinting to identify its conserved regions. I then applied CRISPR/Cas9-mutagenesis
to introduce a large variety of mutations in these sequences. Several mutants
exhibited extended periods of bud dormancy. Additionally, I confirmed the
binding of specific TF families to these conserved regions. These results
underscore the highly conserved BRC1 regulation across different plant
species and enlighten the critical regulators involved in BRC1-dependent
axillary bud outgrowth. Decoding these regulatory sequences could enhance our
understanding of bud development, therefore contributing to the improvements of
plant architecture in the future.