A novel R2R3-MYB transcription factor LlMYB305 from Lilium longiflorum plays a positive role in thermotolerance via activating heat-protective genes

•LlMYB305 is a homology of AtMYB21 and AtMYB24 from Lilium longiflorum.•LlMYB305 is induced by heat stress, and also specially expresses in the later developmental stages of anther.•The conserved C-terminal motif of LlMYB305 contributes to its transactivation ability.•LlMYB305 may be an up-stream regulator of LlHSC70 in Lilium longiflorum.•LlMYB305 acts as a positive regulator of thermotolerance in Lilium longiflorum.