Plant growth-promoting bacteria (PGPB) enhance plant growth, as well as protect plants from several biotic and abiotic stresses through a variety of mechanisms. Therefore, the exploitation of PGPB in agriculture is feasible as it offers sustainable and eco-friendly approaches to maintaining soil health while increasing crop productivity. The vital key of PGPB application in agriculture is its effectiveness in colonizing plant roots and the phyllosphere, and in developing a protective umbrella through the formation of microcolonies and biofilms. Biofilms offer several benefits to PGPB, such as enhancing resistance to adverse environmental conditions, protecting against pathogens, improving the acquisition of nutrients released in the plant environment, and facilitating beneficial bacteria–plant interactions. Therefore, bacterial biofilms can successfully compete with other microorganisms found on plant surfaces. In addition, plant-associated PGPB biofilms are capable of protecting colonization sites, cycling nutrients, enhancing pathogen defenses, and increasing tolerance to abiotic stresses, thereby increasing agricultural productivity and crop yields. This review highlights the role of biofilms in bacterial colonization of plant surfaces and the strategies used by biofilm-forming PGPB. Moreover, the factors influencing PGPB biofilm formation at plant root and shoot interfaces are critically discussed. This will pave the role of PGPB biofilms in developing bacterial formulations and addressing the challenges related to their efficacy and competence in agriculture for sustainability.

Combating the consequences of climate change is extremely important and critical in the context of feeding the world’s population. Crop simulation models have been extensively studied recently to investigate the impact of climate change on agricultural productivity and food security. Drought and salinity are major environmental stresses that cause changes in the physiological, biochemical, and molecular processes in plants, resulting in significant crop productivity losses. Excessive use of chemicals has become a severe threat to human health and the environment. The use of beneficial microorganisms is an environmentally friendly method of increasing crop yield under environmental stress conditions. These microbes enhance plant growth through various mechanisms such as production of hormones, ACC deaminase, VOCs and EPS, and modulate hormone synthesis and other metabolites in plants. This review aims to decipher the effect of plant growth promoting bacteria (PGPB) on plant health under abiotic soil stresses associated with global climate change (viz., drought and salinity). The application of stress-resistant PGPB may not only help in the combating the effects of abiotic stressors, but also lead to mitigation of climate change. More thorough molecular level studies are needed in the future to assess their cumulative influence on plant development.

Bacillus cereus s.l., Gram-positive endospore-forming bacilli, persist ubiquitously in different natural habitats and play various ecological roles. Nevertheless, although chitin is one of the most abundant polymer on Earth, the study of the ability of B. cereus s.l. to hydrolyze this polymer were limited to individual B. cereus and B. thuringiensis strains only. Thus, to fill this gap in this research we focused on (i) the linkage between the capability to chitin degradation and the phylogenetic relatedness of B. cereus s.l. strains, and (ii) the genetic background of chitinolytic properties of these bacilli. Our results showed that chitin degradation is common among the B. cereus group members, yet strains clustered into particular phylogenetic groups differ in their chitinolytic capacity. Separate clustering of chitinolytic and non-chitinolytic strains in the phylogenetic tree indicates the ecotypic structure of these isolates. Two proteins belonging to subfamily A (ChiA) and subfamily B (ChiB) of the glycoside hydrolase GH18 family exhibited simultaneous chitobiosidase and endochitinase activities, and are responsible for chitin utilization by environmental B. cereus s.l. isolates.

Rapeseed (Brassica napus L.) is a globally significant oilseed crop with high economic value. However, water deficit significantly limits its growth and productivity. Exopolysaccharides (EPS)‐producing bacteria offer a promising strategy to counteract drought stress, leveraging their high water retention capabilities and plant growth‐promoting (PGP) properties. This study was conducted to characterize the PGP traits of selected EPS‐producing bacteria strains and evaluate its efficacy in enhancing rapeseed resilience under drought conditions. Among five EPS‐producing bacteria evaluated, Pseudomonas protegens ML15 was selected for its best performance. This strain demonstrated a range of plant growth‐promoting traits, such as the solubilization of phosphate, potassium, and zinc, alongside the production of ammonia, siderophores, and proline. It also exhibited antioxidant activity and the ability to form biofilms, even under water‐stressed conditions. Inoculation of rapeseed with strain ML15 increased germination percentages and seedling length. Notably, whether rapeseed plants were subjected to drought‐induced stress or maintained under normal conditions, treatment with P. protegens ML15 inoculation consistently improved plant length and overall biomass. Under drought‐stressed conditions, inoculated plants exhibited reduced malondialdehyde levels and increased vegetation indices, chlorophyll, protein, proline, and phenolic content. They also showed enhanced activity of antioxidant enzymes, such as catalase and peroxidase, compared to uninoculated rapeseed plants. These findings underscore the potential of EPS‐producing bacteria like P. protegens ML15 to mitigate water stress in plants, providing ecological and economic benefits that support agricultural sustainability.