Conserved and species-specific guard cell transcriptional responses and drought physiology in Arabidopsis and tomato

Crop productivity is severely threatened by climate change-related stresses, including drought stress. During drought, physiological and transcriptional changes occur in guard cells to regulate stomatal closure and minimize excess water loss. Tomato is an important crop species in temperate regions, with a high water requirement. To further understand the drought response in tomato, we performed RNA-seq on guard cell-enriched samples of plants subjected to severe drought stress. We investigated drought-responsive changes in gene expression and alternative splicing, including the role of ABA signaling genes. Comparing this data to previous work on the model species Arabidopsis thaliana , we highlighted an increased level of transcriptional reprogramming in tomato. These differences translated to the physiological level, where we observed earlier stomatal closure during progressive drought in tomato compared to A. thaliana using thermal imaging. Overall, this study sheds new light on tomato GCs during drought, and emphasizes the importance of translational studies on crop species.