New state-of-the-art imaging tools to study how crops adapt to environmental changes: Lycopersicum esculentum key study

Plants, as sessile organisms, constantly face environmental challenges, including abiotic factors, like water scarcity, and biotic stresses, such as pathogen attacks, which significantly influences plant growth and crop yield. Consequently, understanding the mechanisms of plant responses to external stimuli becomes crucial. So far, much research conducted on molecular pathways involved in the transmission of stimuli perception to plant responses comes from Arabidopsis thaliana studies. To reveal how crops perceive and cope with environmental stimuli we directed our focus toward tomato, Lycopersicon esculentum, due to its global economic importance and its susceptibility to adverse conditions. To deepen our understanding of the roles played by different second messengers in signal transduction pathways within crops, we generated MicroTom tomato plants expressing the genetically encoded biosensors Cameleon YC3.6 and pH-GFP to analyse cytosolic calcium (Ca2+) and pH dynamics, respectively. So far, we have successfully selected plants that exhibit favourable expression of the two sensors within guard cells and pollen tubes. Through fluorescence microscopy analysis of the Cameleon line, we observed spontaneous cytosolic Ca2+ oscillations occurring in both guard cells and at the tip of growing pollen tubes. Concerning the pH-GFP plants, we were able to verify the proper sensor functionality in guard cells. Whereas our preliminary analyses reveal the functionality of the sensors in MicroTom plants, we are facing difficulties on selecting plants with uniform expression of the sensors in different tissues, and not only limited to guard cells and pollen tubes. Attempts to improve the transformation protocol are undergoing.