Effect of phytohormone on proliferation and accumulation of cellular metabolites of microalgae Isochrysis zhanjiangensis

[Display omitted] •Phytohormones in cells of IZ and strain 3005 are different at different temperatures.•Elevated endogenous JA in wild-type algae under high temperature conditions.•IBU can enhance the high-temperature tolerance and antioxidant activity of IZ.•IBU upregulate genes involved in the photosynthesis pathway of strain IZ. Phytohormones play a role in regulating microalgae cells tolerance to adversity. This paper examines the effects of different temperatures (20 °C, 25 °C, 30 °C and 35 °C) on the physiological characteristics and endogenous phytohormones of the Isochrysis Zhanjiangensis (IZ) and its mutagenic strain (3005). The results showed that the endogenous phytohormones indole acetic acid (IAA) and jasmonic acid (JA) exhibited significant differences (P