Plant materials
One-year-old tea plants (Camellia sinensis cv. Longjing 43) were placed in plastic pots and grown in a plant growth room at 25 ℃ with a 14-h-light/8-h-dark cycle for two months. The Columbia-0 (Col-0) ecotype of Arabidopsis was grown in a growth chamber at 22 °C, and the parameter 16-h-light/8-h-dark cycle was used. The athsfa2 mutant was provided by Dr. Yee-Yung Charng. Transgenic plants Col-0 andathsfa2 overexpressing CsHSFA1b/CsHSFA2 were generated by cloning the corresponding cDNA fragment into pCAMBIA2300 (kanamycin-resistant) and the 35S promoter was used as control. These constructs were transformed into Agrobacterium strain GV3101. Using the floral dip method, the bacteria were subsequently introduced into Arabidopsis plants (Clough and Bent, 1998).