HsfA1a confers pollen thermotolerance through upregulating antioxidant capacity, protein repair, and degradation in Solanum lycopersicum L.The heat shock transcription factors (Hsfs) play critical roles in plant responses to abiotic stresses.  However, the mechanism of Hsfs in the regulation of pollen thermotolerance and their specific biological functions and signaling remain unclear.  Herein, we demonstrate that HsfA1a played a key role in tomato pollen thermotolerance.  Pollen thermotolerance was reduced in hsfA1a mutants but was increased by hsfA1a overexpression, based on pollen viability and germination.  Furthermore, HsfA1a bound to the promoter region of genes involved in redox regulation (Cu/Zn-SOD, GST8, and MDAR1), protein repair (HSP17.6A, HSP70-2, HSP90-2, and HSP101) and degradation (UBP5, UBP18, RPN10a, and ATG10) and regulated the expression of these genes in tomato anthers under heat stress.  Our findings suggest that HsfA1a maintains pollen thermotolerance and cellular homeostasis by enhancing antioxidant capacity and protein repair and degradation, ultimately improving pollen viability and fertility.
THERM