Cryptochrome 1 attenuates plant heat stress response by light-heat stress response signal pathways crosstalk in Arabidopsis
Plants regulate growth and development in different  ambient environments through light signaling pathways and heat stress signaling pathways, both of which are very important for plant adaptation to the environment, but whether there is an interaction between the two is still unclear. In this article, we reported that the blue light receptor Cryptochrome CRY1 phosphorylation will be inhibited under high temperature stress, and CRY1 activity will decrease; at this time, CRY1 could not interact with E3 ubiquitin ligase COP1(CONSTITUTIVELY PHOTOMORPHOGENIC 1) and COP1 activity increased. Its substrate HY5(ELONGATED HYPOCOTYL 5)is continuously degraded under heat stress. Through further transcriptome analysis, we found that the substrates of HY5 have a class of HSFAs(HEAT SHOCK FACTOR)HSFA2/HSFA7As/HSFA7Bs transcription factors, which are rapidly induced under heat stress conditions and activate downstream HSPs (HEAT SHOCK PROTEIN)expression.Under normal conditions, HY5 protein inhibits HSFA2/HSFA7As/HSFA7Bs. Under heat stress, HY5 protein is degraded, which releases the expression of HSFAs, thereby enhancing plant heat tolerance. In this paper, we put forward the hypothesis that the phosphorylation of CRY1 seems to be a switch in the ambient environment , and through the regulation of phosphorylation level, the light and heat stress signal are transmitted downward, forming an light-heat signal interactive regulation pathway to regulate the growth and development of plants. Overall design: WT and cry1 mutant were grown under continuous light at 22°C for 7 days and then transferred to blue light for 1 day. Then part of them was transferred to 44°C blue light for heat treatment, and part continued to grow at 22°C. Samples were taken for RNA-seq after 2 hours.