The heat stress transcription factors HsfA3a/b enhance heat stress resistance by regulating HSP26.5-1/-2 in Sorbus pohuashanensis.

SpHsfA3a/b directly regulate SpHSP26.5-1/-2 and enhance heat stress resistance in Sorbus pohuashanensis.

• Why it matters: Understanding heat tolerance mechanisms in woody plants like S. pohuashanensis is crucial for improving their resilience amid rising global temperatures, yet their regulatory pathways remain poorly understood.
• What they did: Researchers isolated and characterized SpHsfA3a/b and SpHSP26.5-1/-2, then overexpressed these genes in Arabidopsis thaliana and complemented hsfa3 mutants, analyzing gene expression, physiological responses, and promoter binding.
• The result: Overexpression and complementation increased plant survival under heat stress, with associated changes in stress-related metabolites and enzyme activities, confirming that SpHsfA3a/b directly activate SpHSP26.5-1/-2 to improve thermotolerance.