Light as a stressor and its impact on biotic and abiotic stress responses in plants

Abstract

Light is important for plant life as a source of energy to drive photosynthesis but also as an environmental signal regulating development or cellular events such as resetting of the circadian clock. Light itself can cause stress such as excess light, fluctuating light, photoperiod and ultraviolet light stress. Light quality, quantity and light duration are important sources of information to prepare plants for future light stress events. Recurring light stress results in acclimation processes to the changing light environment. Furthermore, light regulates the responses of plants to diverse biotic and abiotic stresses. For example, short day conditions or shady environments prime thermotolerance and increase cold acclimation. Similarly, during drought stress, light signaling is important for the plant s stress response. Additionally, the light environment affects the plant s responses to biotic intruders such as pathogens or insect herbivores. Light influence many stress responses resulting in positive growth-defense trade-offs. Under shade, however, plants prioritize growth over defense and stress responses. In this review, we summarize the impact of light as a stressor and its influences on abiotic and biotic stress responses with special focus on the role of the different light receptors and the crosstalk between light signaling components and stress response pathways. ACKNOWLEDGEMENTSWe acknowledge funding by Deutsche Forschungsgemeinschaft (DFG) through Collaborative Research Centre 973 (www.sfb.973) and project Schm 814/29-1. There are no conflicts of interests.