2.1 BRs play a positive role in thermomemory
To elucidate the role of BRs in thermomemory in Arabidopsis , we
performed a thermotolerance assay under primed and unprimed conditions
towards wild-type Col-0. Heat priming and triggering protocol was
outlined in Fig. 1A. Seedlings grown on standard half-strength
Murashige-Skoog (1/2MS) medium with or without 10 nM BL (brassinolide, a
kind of BRs with high physiological activity) were vibrant before HS.
Upon HS triggering and recovery, seedlings grown on the medium
containing BL exhibited significantly enhanced thermotolerance,
accompanied with comparably elevated survival rate and decreased
electrolyte leakage. Thermomemory induced by heat priming effectively
improved the thermotolerance of seedlings and the application of BL
further enhanced the vitality of thermomemory (Fig. 1). These
observations suggest that BRs positively modulate thermomemory process.