The Chlamydomonas heat stress response

Heat waves occurring at increased frequency as a consequence of global warming jeopardize crop yield safety. One way to encounter this problem is to genetically engineer crop plants toward increased thermotolerance. To identify entry points for genetic engineering, a thorough understanding of how plant cells perceive heat stress and respond to it is required. Using the unicellular green alga Chlamydomonas reinhardtii as a model system to study the fundamental mechanisms of the plant heat stress response has several advantages. Most prominent among them is the suitability of Chlamydomonas for studying stress responses system-wide and in a time-resolved manner under controlled conditions. Here we review current knowledge on how heat is sensed and signaled to trigger temporally and functionally grouped sub-responses termed response elements to prevent damage and to maintain cellular homeostasis in plant cells. Significance Statement Heat waves occurring with increased frequency as a result of global climate change threaten crop yield safety. Countermeasures may lie in the genetic engineering of crop plants toward higher thermotolerance, for which a thorough understanding of how plants sense heat and respond to it is imperative. This review gives a comprehensive overview to this issue with a strong focus on data from Chlamydomonas reinhardtii.