CHLOROPLAST SENSOR KINASE modulates growth and UV-B tolerance in Arabidopsis thaliana

<p><span>Increased levels of UV-B radiation are anticipated to occur under climate change, requiring a comprehensive understanding of its potential impact on plant physiology and development. Thus, it is crucial to grasp the mechanisms that allow plants to acclimate to this altered environmental scenario. In our study, <em>CHLOROPLAST SENSOR KINASE (CSK) </em>has emerged as a pivotal element influencing both plant development and tolerance to UV-B stress. Here we show that <em>CSK</em> plays a significant role in maintaining the integrity of the photosynthetic machinery and minimizing oxidative damage, interacting with SIGMA FACTORs 1 and 5 and operating in a UV-B dose-dependent manner and independently of <em>UV RESISTANCE LOCUS 8 (UVR8) </em>expression. Moreover, <em>CSK</em> expression is regulated by <em>ELONGATED HYPOCOTYL 5 (HY5)</em> and cryptochromes, highlighting the complex interplay between these molecular elements in regulating plant responses to UV-B exposure. These results shed light on potential avenues for further research and plant adaptation strategies in the face of climate change.</span></p>