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.
Laura Amaya-Quiroz, M. Kaddoura, M. Rani et al.· Frontiers in Plant Science· 0 citations
Bacterial endophytes are increasingly recognized for their ability to enhance plant growth and productivity through multiple physiological and biochemical mechanisms. However, how these responses are coordinated across plant developmental stages and translate into final crop performance remains unclear. This study evaluated previously characterized bacterial endophytes belonging to Bacillus subtilis (BS-114, BS-120) and Pseudomonas wadenswilerensis (PPW-26) as plant growth-promoting agents in yellow bean under in vitro, greenhouse, and field conditions. Bacterial treatments enhanced early developmental responses relative to the non-inoculated control (NC), with BS-114 increasing germination (+19.1%) and seedling total root length (+71.3%), while PPW-26 increased root biomass (+61.7%). Under greenhouse conditions, BS-114 improved reproductive development, increasing bud count (+47.4%), immature pod count (+60.2%), and pod fresh mass (+42.1%). Cell-free extracts reproduced several of these beneficial effects, with the BS-114 cell-free extract (BS-114E) producing the highest cumulative pod fresh mass (+94.2%), suggesting the contribution of extracellular components to reproductive performance. Physiological and gene-expression analyses further indicated that treatment responses were not attributable to a single pathway. Among the measured gas-exchange parameters, photosynthetic rate increased (+175.8%) and stomatal conductance increased (+306.9%). Gene expression analyses showed treatment-specific upregulation of selected genes, with N-fixation-related expression (nifH) reaching +5.62 log2FC (49.31×) with the BS-114 live-cell treatment (BS-114L), while hormone-related responses were characterized by coordinated upregulation of auxin signaling-related expression +5.24 log2FC (37.89×) and cytokinin-related expression patterns consistent with increased biosynthesis and reduced degradation. Field validation showed that all treatments increased yield relative to NC, with the BS-114+BS-120 consortium achieving a +32.65% increase, which was comparable to NPK (+37.76%), despite limited shifts in soil microbial diversity and moderate variation in soil nutrients. Together, these findings indicate that the evaluated bacterial treatments improved plant performance through coordinated responses across multiple biological levels and plant developmental stages, supporting their application as plant growth-promoting agents under controlled and field conditions.
M. Kaddoura, Laura Amaya-Quiroz, J. Samsatly et al.· Frontiers in Plant Science· 1 citation
The use of the tested biostimulant treatments support the use of the tested biostimulants as sustainable crop management tools that preserve rhizosphere microbial communities.
Oumaima Akachoud, Paola Villanueva Rosales, J. Fontaine et al.· Agriculture· 0 citations
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