2) Ms. Noa Assaf

Plant-microbe interactions play a crucial role in plant adaptation to environmental stresses. However, the mechanisms underlying the co-evolution of plants and their microbiota remain poorly understood. Plants exude a significant portion of their photosynthetic products, influencing the rhizosphere in response to environmental changes. However, the extent to which plants actively recruit specific microbiota to cope with extreme conditions is still unclear. This study examined evolutionary responses of desert plants to drought stress that involve communication with microorganisms. We grew Isatis microcarpa, a species from arid climate, and Isatis lusitanica, a species from Mediterranean climate, and compared their drought-stress responses. We demonstrate that the southern I. microcarpa is more drought-resistant than I. lusitanica by I.microcarpa’s ability to maintain photosynthetic efficiency and higher shoot mass even under drought conditions. Additionally, we found that I. microcarpa exhibits larger total organic carbon under drought and shows a more pronounced metabolic response to drought stress in its root exudate profile, with a greater number of metabolites significantly regulated in response to drought compared to I. lusitanica, which may indicate the plant’s attempt to shape its microbiota in a way that helps cope with the stress. We are currently characterizing the rhizosphere microbial community in each species and treatment, as well as genes expressed in the different plant species under drought stress. These results expand our knowledge about the relationship between plants and their microbiota, and have the potential to suggest future methods for making agricultural crops more resistant to climate change and desertification.