Reactive oxygen species-mediated signal transduction and utilization strategies in microalgae

Reactive oxygen species (ROS) are crucial in stress perception, the integration of environmental signals, and the activation of downstream response networks. This review emphasizes ROS-mediated signaling pathways in microalgae and presents an overview of strategies for leveraging ROS. Eight distinct signaling pathways mediated by ROS in microalgae have been summarized, including the calcium signaling pathway, the target of rapamycin signaling pathway, the mitogen-activated protein kinase signaling pathway, the cyclic adenosine monophosphate/protein kinase A signaling pathway, the ubiquitin/protease pathway, the ROS-regulated transcription factors and enzymes, the endoplasmic reticulum stress, and the retrograde ROS signaling. Moreover, this review outlines three strategies for utilizing ROS: two-stage cultivation, combined stress with phytohormones, and strain engineering. The physicochemical properties of various ROS, together with their redox reactions with downstream targets, have been elucidated to reveal the role of ROS in signal transduction processes while delineating the ROS-mediated signal transduction network within microalgae.