Plants are increasingly subjected to concurrent heat stress and elevated CO2, yet how they perceive and integrate these combined stresses remains poorly understood. Here, we identified β-carbonic anhydrase βCA2 as a central signaling hub in tomato that decodes these combined stresses. We demonstrated that βCA2 physically interacts with the receptor kinase PSKR1 at the plasma membrane, and the phosphorylation of βCA2 by PSKR1 is significantly enhanced when both CO2 and heat stress converge. We pinpointed Serine-231 as the crucial phosphorylation site on βCA2. Activation of βCA2 via Ser231 phosphorylation is essential for the accumulation of phosphatidic acid (PA), a lipid signaling molecule that helps protect the plant from heat damage. These findings provide new insights into the complex integration of environmental stress signals through βCA2 and emphasize the critical role of CO2-heat interactions in plant stress responses. Our findings not only deepen the understanding of plant adaptation to climate change but also provide potential targets for developing climate-resilient crops.
Lv et al. (Sun,) studied this question.