PgMYB96 enhances Physalis grisea high temperature tolerance by activating trithorax-like factor WD REPEAT CONTAINING5b.

Abstract

Under the general trend of global warming, high temperature stress (HTS) is an increasingly grievous challenge to the normal growth and development of crops. Exposure to high temperature (42°C) during the growth and development stages of Physalis grisea can result in the breakdown of antimicrobials, sterility of pollen, and diminished yields. In this study, trithorax-like factor PgWDR5b was functionally analysed in response to high temperature stress in P. grisea. PgWDR5b expression was enhanced through treatments with HTS and abscisic acid (ABA), PgWDR5b promoted the level of expression of downstream ABA synthesis genes after HTS, and positively contributes to tolerance to high temperature stress in P. grisea. In addition, the transcription factor PgMYB96 binds the promoter of PgWDR5b. Silencing both PgWDR5b and PgMYB96 reduced the high temperature tolerance of the P. grisea, as well as the synthesis genes for ABA showed decreased expression while the catabolic genes had increased levels of expression. The results of overexpression assay were contrary. Furthermore, ABA directly activates PgWDR5b expression. These results collectively suggest that PgMYB96 can both regulate PgWDR5b expression by affecting ABA synthesis and directly activate PgWDR5b transcription. Hence, PgWDR5b can participate in the high temperature stress response of P. grisea through the metabolic pathway of ABA and establishes a positive feedback regulatory mechanism with ABA.