Microbial intervention by <i>Acinetobacter schindleri</i> SR-5-1 alleviates cadmium toxicity in pea cultivation

Cadmium (Cd) contamination of agricultural soils disrupts plant signaling networks, impairing nutrient communication, photosynthetic efficiency, and stress responses. Microbial inoculants offer eco-biotechnological solutions by modulating signal perception and transduction under heavy metal stress. This field study investigated the role of Acinetobacter schindleri strain SR-5-1 in influencing pea (Pisum sativum L.) signaling pathways under Cd toxicity. Plants exposed to environmentally relevant Cd concentrations (250 and 500 µM) exhibited disrupted chlorophyll biosynthesis, elevated oxidative stress markers, and impaired nutrient signaling. Inoculation with SR-5-1 restored chlorophyll levels, enhanced ROS-scavenging enzyme activities, and reduced lipid peroxidation, indicating microbial effects on oxidative signaling cascades. Importantly, the inoculated plants accumulated less Cd in the roots and leaves, reflecting microbial mediation of ion transporter activity and rhizosphere detoxification. SR-5-1 also improved nitrogen, iron, zinc, potassium, and magnesium acquisition, highlighting its role in nutrient uptake and homeostasis. These findings demonstrate that SR-5-1 functions as a bio-communicator, alleviating xenobiotic stress by modulating ROS and nutrient signaling pathways. The study underscores the ecological relevance of microbial inoculants in supporting integrative plant communication and resilience, positioning SR-5-1 as a promising bioresource for signaling-driven sustainable agriculture in Cd-affected soils.