Mycorrhizal symbiosis-induced abiotic stress mitigation through phosphate transporters in Solanum lycopersicum L

Arbuscular mycorrhizal (AM) symbiosis and abiotic stress mitigation have intrigued researchers for more than a century, but how different phosphate transporters, such as members of the Pht1 gene family, are influenced during the combined presence of AM fungi and stress is not well known. In this study, the impact of AM fungi (Funneliformis mosseae) on tomato plants under water deficit and heat stress was investigated via observing the physiological changes and applying spectrophotometric and quantitative real-time PCR methods, with a focus on phosphate transporters (Pht1;1, Pht1;3, Pht1;4, Pht1;6, Pht1;7 and Pht1;8). Moreover, genes encoding heat-responsive proteins (HSFA2 and HSP70) and aquaporins (PIP2.5 and PIP2.7) were also studied. On the basis of our results, AM fungi seemingly mitigated heat and combined (heat and water deficit) stresses through the mediation of the expression of Pht1 family phosphate transporter genes. In addition to the Pht1;3 and Pht1;4 genes, Pht1;7 also seems to be an AM fungus-inducible phosphate transporter gene. The results of this study may provide insights into the behavior of phosphate transporter gene family members and a potential strategy to enhance the vigor of tomato plants through increased phosphorous uptake under heat stress, water deficit and heat and water deficit combined.