Cyanobacterial bioformulations enhance growth and stress resilience in maize genotypes under moisture-limited conditions

Cyanobacteria-maize-moisture stress interactions were evaluated in mesocosm experiments using autoclaved and non-autoclaved soil, as options to improving plant vigour and stress resilience in two maize (Zea mays) genotypes. The investigation focused on priming seeds with cyanobacterial formulations: BF1-4 (Cyanobacterial consortium) and Anabaena torulosa-Trichoderma viride (An-Tr) biofilm, and comparing with recommended doses of fertilizers at 75% and 50% water-holding capacity (WHC), representing optimum and restricted moisture conditions respectively. Sampling at 3 WAS (weeks after sowing) and flowering stage revealed that both BF1-4 and An-Tr (+ 75% recommended N dose and full doses of P and K), significantly improved maize growth, with 4-16% increase in biometric and growth parameters, even under moisture stress. Distinct genotype-specific responses with lower decline in biomass along with enhanced soil nutrient availability under stress was recorded in V6 (HKI323PV), as compared to V7 (HKI161PV). In non-autoclaved soil, the bioformulations significantly enhanced by 1.7-fold increase in microbial biomass carbon, soil dehydrogenase activity, and soil chlorophyll. Bioformulation-treated plants alleviated moisture stress with 1.2-4-fold enhanced activities of carbon and nitrogen assimilation enzymes, even with 75% recommended N dose. This was also evidenced by the elevated proline and relative water content, as well as positive influence on flowering attributes and drought-related delays, which correlated with increased soil available nitrogen and organic carbon. Significant regulation of soil biological and enzymatic activities was recorded under both moisture levels, by BF1-4 and An-Tr, differentially in both genotypes. Integrating cyanobacterial bioformulations can be a promising approach to improved plant vigour under moisture stress in maize, with 25% N savings.