Symbiotic Aspergillus terreus alleviates drought and waterlogged stress in Zea mays L.

The interaction concerning rhizospheric fungi and plants is essential for enhancing plant resilience in the face of abiotic stress conditions. This study investigated the effects of the rhizospheric fungus Aspergillus terreus on maize (Zea mays L.) growth under both drought and waterlogging conditions. Our findings confirmed that inoculation with A. terreus mitigated the adverse effects of drought and waterlogging conditions on maize growth. Plants treated with Aspergillus terreus (A. terreus) exhibited enhanced root and shoot length, fresh and dry weight as well as enhanced chlorophyll content in plants compared to control, under stress-related conditions. Compared to the control group, A. terreus significantly increased the level of chlorophyll "a" by 8.14%, chlorophyll "b" by 19.04%, and total chlorophyll by 6.04% under drought stress and by 25.04%, 11% and 7.26% under waterlogging stress conditions, effectively restored chlorophyll levels in stress induced plants. Inoculated plants demonstrated elevated levels of phytohormone, specifically SA (18.27%) compared to the untreated control group, correlating with improved stress tolerance. Enzymatic investigation revealed that A. terreus affected the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), leading to a notable increase in catalase activity and a reduction in electrolyte leakage, thereby enhancing membrane integrity under stress conditions. Additionally, plants infected with A. terreus showed reduced levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), suggesting a reduction in oxidative damage. Microscopic analysis confirmed the successful colonization of roots by A. terreus, which facilitated plant growth in both arid and waterlogged conditions. These results reveal that the bioinoculant such as A. terreus induces Zea mays L. resistance to water-related stress by modulating the phytohormones and antioxidant enzyme activities. This provides a sustainable means of increasing crop health under stress growing circumstances and explore the possible use of rhizospheric A. terreus in agricultural biotechnology.