title: Chloroplast Retrograde Regulation of Heat Stress Responses in Plants.
abstract: It is well known that intracellular signaling from chloroplast to nucleus plays a vital role in stress responses to survive environmental perturbations. The chloroplasts were proposed as sensors to heat stress since components of the photosynthetic apparatus housed in the chloroplast are the major targets of thermal damage in plants. Thus, communicating subcellular perturbations to the nucleus is critical during exposure to extreme environmental conditions such as heat stress. By coordinating expression of stress specific nuclear genes essential for adaptive responses to hostile environment, plants optimize different cell functions and activate acclimation responses through retrograde signaling pathways. The efficient communication between plastids and the nucleus is highly required for such diverse metabolic and biosynthetic functions during adaptation processes to environmental stresses. In recent years, several putative retrograde signals released from plastids that regulate nuclear genes have been identified and signaling pathways have been proposed. In this review, we provide an update on retrograde signals derived from tetrapyrroles, carotenoids, reactive oxygen species (ROS) and organellar gene expression (OGE) in the context of heat stress responses and address their roles in retrograde regulation of heat-responsive gene expression, systemic acquired acclimation, and cellular coordination in plants.
authors.affiliation: The National Key Laboratory of Plant Molecular Genetics, National Center of Plant Gene Research (Shanghai) and CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences Shanghai, China.
authors.forename: Ai-Zhen
authors.initials: AZ
authors.lastname: Sun
authors.affiliation: The National Key Laboratory of Plant Molecular Genetics, National Center of Plant Gene Research (Shanghai) and CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences Shanghai, China.
authors.forename: Fang-Qing
authors.initials: FQ
authors.lastname: Guo
keywords: chloroplast; heat stress responses; plastid signal molecules; reactive oxygen species (ROS); retrograde signaling