The DAY1-SnRK1 modue is a key survival strategy under long-term drought stress via chloroplast degeneration and suppression of translation
Plants are a sessile and autotrophic organism. Thereby, responses to drought stress are highly complicated. Drought stress causes a problem in water relations and also interferes with autotrophic energy production via inhibition of photosynthesis. The latter phenomenon is specific to plants and brings another serious problem, accumulation of excess amounts of ROS, highly toxic compounds. Thus, drought stress, in particular during long period of time, is a serious threat to plant survival by affecting both water relations and energy production. However, how plants response to the long-term drought stress remains elusive. In this study, we provide evidence that a newly identified module consisting of DAY1-SnRK1 plays a key role in adaptation to long-term drought stress. DAY1, a leucine-rich repeat receptor-like kinase, that had a malectin domain with pectin binding ability showed dehydration-dependent cell wall binding and activated SnRK1-alpha via direct interaction. Activation of this module by long-term ABA treatment leads to chloroplast degeneration and suppression of translation-related processes, leading to a quiescent state of life preservation.