*4.2. Plant Treatments*

The seedlings of *H. villosa* were grown in liquid or soil until the three-leaf stage. For heat shock or drought stress treatment, the plants were transferred to 42 ◦C conditions, or dipped into 20% PEG 6000 and leaves were sampled at 0, 1, 6, or 12 h after treatment. For powdery mildew treatment, the plant was inoculated with pathogen isolate *E26* and the leaf tissues were sampled at 0, 24, 48 and 72 h after inoculation. For phytohormones and H2O<sup>2</sup> treatments, the plants were sprayed with 5 mmol salicylic acid (SA), 0.1 mmol methyl jasmonate (MeJA), 0.1 mmol ethephon (ET), 0.2 mmol abscisic acid (ABA) and 7 mmol hydrogen peroxide (H2O2), respectively and all leaf tissues were collected at 0, 6, 12, or 24 h after spraying [78]. All the samples were rapidly frozen in liquid nitrogen, then stored in an ultra-freezer (−80 ◦C) before use.
