The role of arbuscular mycorrhizal symbiosis in maintaining potassium uptake in bean under drought and ABA stress

Potassium, as a key element, plays a prominent role in regulating cellular activities and stress responses in plants. However, its availability to plants is limited due to strong adsorption by soil aggregates. In this study, the effects of symbiosis with mycorrhizal fungi, Funneliformis mosseae and Rhizophagus irregularis on potassium uptake and the expression of AKT and HKT genes under drought stress and ABA application in bean were investigated. The results revealed that the concentration of potassium in root and shoot tissues increased in response to symbiosis with arbuscular mycorrhizal fungi (AMFs). Additionally, under both control and drought conditions, AMF-colonized plants maintained higher potassium concentrations compared to non-symbiotic plants. Cellular location prediction revealed that most PvAKT, except PvAKT9 and PvAKT14, were localized to the plasma membrane. RNA-seq data analysis showed that the PvAKT and PvHKT genes exhibited differential expression in response to salt stress. Furthermore, qPCR results indicated that drought conditions and AMF symbiosis enhanced the expression of PvAKT genes. The expression profile of PvHKT genes indicated that symbiotic relationships significantly enhanced their transcriptional activity in root tissues. These findings indicate that PvAKT and PvHKT genes respond to AMF symbiosis and abiotic treatments and are associated with potassium transport in bean roots. Overall, our results suggest that some PvAKT genes respond to ABA treatment, although their direct involvement in ABA signaling pathways requires further functional validation.