Temperature-responsive transcription factor SbHSF24 promotes flavonoid glycoside accumulation in Scutellaria baicalensis by activating UBGAT

Temperature is a decisive factor affecting the yield and quality of the medicinal crop Scutellaria baicalensis Georgi. As global climate change threatens traditional cultivation zones, deciphering the molecular mechanisms underlying temperature-dependent metabolite biosynthesis is critical for sustainable agriculture. Here, we explored the physiological and metabolic responses of S. baicalensis to different thermal regimes. We discovered that while high temperatures disrupt redox homeostasis and reduce medicinal quality, low temperatures trigger a "metabolic compensation" mechanism. Specifically, despite inhibited vegetative growth under cold environment, this mechanism ensures the sustained accumulation of key bioactive flavonoid glycosides, such as baicalin and wogonoside. Through integrated multi-omics and molecular analyses, we identified the heat shock transcription factor SbHSF24, which is upregulated in response to low temperature. SbHSF24 drives this metabolic compensation by directly binding to and activating the promoter of UDP-baicalein 7-O-glucuronosyltransferase ( UBGAT ), enhancing downstream flavonoid glycosylation. Ultimately, our results establish a fundamental "low temperature-SbHSF24-UBGAT" regulatory axis. This axis clarifies how S. baicalensis maintains its geo-authentic medicinal quality in cool environments and provides critical genetic targets for the sustainable cultivation and molecular breeding of high-quality medicinal crops in the face of global warming. • Low temperature promotes flavonoid glycoside accumulation in S. baicalensis . • Heat stress disrupts redox homeostasis and induces aglycone accumulation. • SbHSF24 activates UBGAT transcription to enhance flavonoid glycosylation.