thermomorphogenesis
Thermomorphogenesis refers to the suite of developmental and architectural changes plants undergo in response to elevated ambient temperature, including elongated stems, hyponastic (upward-angled) leaf growth, and altered flowering time. This process is critical for understanding how plants sense and adapt to warming conditions, with molecular pathways centered on temperature-sensitive photoreceptors and transcription factors that reprogram gene expression to balance growth with stress tolerance. Insights into thermomorphogenesis are increasingly valuable for predicting crop performance and resilience under climate change.
open_in_new WikipediaPubMed · 2026-07-04
Scientists discovered a molecular brake called BLH1 that keeps Arabidopsis plants from overreacting to heat. When temperatures rise, this brake gets released, allowing a known growth-promoting circuit to drive the elongation response plants use to cope with warmth.
BLH1 directly suppresses PIF4 at both the gene and protein level, acting as a dual-layer brake on the heat-elongation response.
Plants overexpressing BLH1 are insensitive to high temperature, while plants lacking BLH1 and its relatives show exaggerated heat responses.
BZR1 directly represses BLH1 expression, forming a negative feedback loop within the BZR1-PIF4-auxin-brassinosteroid circuit that prevents runaway thermomorphogenesis.
