Microbial-mediated resilience in tomato (Solanum lycopersicum L.): ecophysiological and molecular signals controlling mycorrhizal and microbiota interactions

Solanum lycopersicum is one of the most relevant horticultural crops worldwide, because of its economic importance, nutritional features and its use as a model system for plant science research. In the context of climate change management, rhizosphere microbes, including arbuscular mycorrhizal fungi (AMF), have emerged as key biological tools to improve plant resilience against environmental stressors, acting as biofertilizers able to enhance the plant performance by modulating key physiological processes such as nutrient uptake, water relations, photosynthesis and oxidative balance. This review provides a comprehensive overview of the ecophysiological and molecular responses induced by tomato plant root microbiota, with special emphasis on AMF, challenged by different abiotic cues. Special attention is given to changes occurring in leaf gas exchange, osmotic adjustment, antioxidant enzyme activity, and hormonal regulation, as well as the transcriptional modulation sustaining these physiological processes. Furthermore, we focus on current omics approaches that are shedding light on the functional dynamics of tomato-microbe interactions, offering insights into plant adaptation strategies under multiple stress conditions. Overall, the review underscores that AMF-mediated benefits are strongly influenced by stress severity and timing, as well as the genotype × AMF strain combination, highlighting the use of local, ad hoc formulations to maximize physiological benefits and stress resilience. It also showcases the need to expand current knowledge under field conditions and emphasizes the crucial role of the tomato microbiome in sustaining plant health and productivity under abiotic stress.