TL;DR
Findings indicate that B. licheniformis strain RGS is a promising seed-applied bioinoculant for enhancing drought resilience and recovery in tomato grown under limited-moisture conditions.
Drought is a major constraint to crop productivity, highlighting the need for sustainable approaches to improve plant resilience. In this study, three endophytic bacteria, Bacillus subtilis BS-114 and BS-116, and Pseudomonas wadenswilerensis PPW-26, previously selected based on their plant growth-promoting traits and genomic potential, were evaluated for their ability to enhance drought resilience in common bean and tomato. Their effects were investigated through in vitro screening under polyethylene glycol (PEG)-induced drought, greenhouse drought validation, and open-field evaluation. Bacterial inoculation improved seed germination, seedling vigor, and plant water status under PEG-induced stress, with strain-dependent responses observed between crops, with the most pronounced effects observed in bean. Under greenhouse drought, inoculated bean plants exhibited improved photosynthetic performance and relative water content, together with reduced oxidative damage and proline accumulation, suggesting enhanced physiological adjustment to water deficit. These responses were associated with changes in the expression of drought-responsive genes involved in abscisic acid signaling, antioxidant defense, and osmoprotection, and were accompanied by a 52% increase in yield compared with non-inoculated drought-stressed plants. Based on greenhouse performance, a consortium containing BS-114 and two additional Bacillus strains was further evaluated under field conditions, where crop productivity was comparable to conventional NPK fertilization and a commercial algae-based biostimulant. Overall, these findings highlight the potential of beneficial endophytic bacteria isolated from medicinal plants to improve drought resilience, accompanied by changes in plant water status, hormonal signaling, and oxidative stress responses.
This study investigated the effects of Sinorhizobium meliloti GAU-93 inoculation on the growth and drought responses of alfalfa (Medicago sativa L.). Alfalfa seeds were inoculated with the GAU-93 strain Sinorhizobium meliloti and subjected to four soil water content levels: 15% (severe drought), 30% (moderate drought), 45% (well-watered control), and 60% (high-moisture condition). Various growth parameters, antioxidant enzyme activities, flavonoid-related traits, and membrane lipid peroxidation were measured. Increasing drought severity reduced plant growth, fresh and dry biomass, and relative water content (RWC). GAU-93 inoculation was associated with smaller reductions in these traits across several water regimes. Inoculated plants also showed higher flavonoid contents and higher expression of several flavonoid biosynthetic genes, including CHS, DFR, F3H, and PAL. In addition, GAU-93 was associated with lower membrane lipid peroxidation and higher antioxidant enzyme activities. Overall, these findings suggest that Sinorhizobium meliloti GAU-93 may help alleviate drought-induced oxidative stress and support alfalfa growth under the tested water regimes. This study provides a basis for further evaluation of GAU-93 as a microbial strategy to improve drought tolerance in forage crops.
The potential of SZ01 as a microbial inoculant to promote plant growth and productivity in saline–alkaline environments, with implications for both medicinal and agricultural crop production, is highlighted.
Principal component analysis indicated that inoculation with the B. velezensis–S.
It is shown that endophytic fungi have the potential to enhance plants’ resilience and provide a promising controlled-environment approach to enhance crop productivity in metal- and salt-contaminated soils.
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