Histone acetyltransferase p300/CBP regulates reproductive diapause via the juvenile hormone pathway in the cabbage beetle, Colaphellus bowringi

Juvenile hormone (JH) serves as a pivotal endocrine regulator of
reproductive diapause in insects, though the molecular mechanisms
governing JH signaling remain poorly characterized. This investigation
assesses the roles of the histone acetyltransferase p300/CBP in mediating
reproductive diapause through JH signaling in the cabbage beetle
Colaphellus bowringi. RNA interference-mediated suppression of p300/CBP in
reproductive female adults induced diapause-like phenotypes, including
arrested ovarian maturation, suppressed vitellogenesis, enhanced lipid
storage, and upregulated expression of diapause-associated genes. Along
with downregulation of key JH biosynthetic enzymes and signaling
components. While exogenous JH application decreased lipid accumulation,
it failed to rescue ovarian developmental arrest. Parallel experiments in
diapausing females with p300/CBP knockdown yielded similar results - JH
analog treatment reduced lipid reserves without stimulating ovarian
development. These findings collectively demonstrate that p300/CBP
regulates photoperiodic reproductive diapause through dual regulation of
JH biosynthesis and signal transduction pathways in C. bowringi. Our
results establish p300/CBP as a critical mediator of JH biosynthesis and
signaling during photoperiod-induced reproductive diapause. This work
advances our understanding of epigenetic regulation in insect diapause and
provides a molecular framework for future studies on environmental
adaptation strategies in insects.