In recent years, nanotechnology has attracted attention in many fields because it has several up-and-coming novel uses. Many researchers have suggested that chitosan nanoparticles (CS-NPs) and their derivatives are one of the best nanomaterials for delivering antibacterial activity. CS-NPs have a broad spectrum of antibacterial activity, but they manifest different inhibitory efficacy against gram-negative (G⁻) and gram-positive (G⁺) bacterial species. The mechanism of antibacterial action is an intricate process that varies between G⁻ and G⁺ bacteria as a result of the differences in cell wall and cell membrane chemistry. In previous studies, greater antibacterial activity was more evident against G⁻ bacteria than G⁺ bacteria, whereas in some studies G⁺ bacteria were more sensitive. Researchers predicted that the varied responses of bacteria are caused by the mixed hydrophilicity and negative charge distribution on the bacterial surface. Moreover, its activity depends on a number of variables including bacterial target (i.e., G⁻ or G⁺ bacteria) and bacterial growth, as well as its concentration, pH, zeta-potential, molecular weight, and degree of acetylation. Therefore, this review examines current research on the mechanisms and factors affecting antibacterial activity, and application of CS-NPs specifically against animal and plant pathogenic bacteria.

Salinity and drought are the major osmotic stress limitations that affect plant growth and crop yield in agriculture worldwide. The alternative response mediated by plants in response to salinity and drought are principally proline accumulation which regulates stress combat strategies owing to sustainable production in the realm of agricultural production even under severe stress. Symbiotic and soil associated arbuscular mycorrhizal fungi (AMF) are regarded as efficient biofertilizers in several crops under these stresses. Summarily AMF is renowned for effective scavengers of free radicals in soil thereby increasing soil parameters optimal for plant growth. AMF contribute to augment host plant tolerance to stress specifically salinity and drought. Mycorrhizal colonization positively regulates root uptake of available nutrients and enhance growth even when bestowed by water constraints which has contributory roles due to proline accumulation providing several intriguing researches on AMF symbiosis pertaining to plant productivity and yield. Mycorrhizal plants and their non-mycorrhizal counterparts show varied expression pattern regarding proline amass. Hence, the precise role of proline with respect to stress tolerance and equivocal mechanisms involved in evasion of osmotic stress has not been extensively reviewed earlier. Further molecular forecasting in this arena is still an underexploited research field. This review comprehensively addresses the observable facts pertaining to proline accumulation upon AMF association and adherence relevant to stress tolerance and host plant efficiency and efficacy.

The present study was to prepare chitosan nanoparticles (CNPs) from chitosan (CS) to evaluate their in vitro antimicrobial activities against phytopathogens of tomato. We prepared and characterized CNPs for their particle size, polydispersity index, and structures. The antifungal properties of CS and CNPs against phytopathogenic fungi namely Colletotrichum gelosporidies, Phytophthora capsici, Sclerotinia sclerotiorum, Fusarium oxysporum, Gibberella fujikuori were investigated. CNPs showed the maximum growth inhibitory effects on mycelial growth of F. oxysporum followed by P. capsici. We also studied antibacterial activities against phytopathogenic bacteria, such as three strains of Erwinia carotovora subsp. carotovora and one strain of Xanthomonas campestris pv. vesicatoria. Our results showed that both CS and CNPs markedly inhibited the growth of the both Xanthomonas and Erwinia strains. From our study, it is evident that both CS and CNPs have tremendous potential against phytopathogens of tomato for further field screening towards crop protection.

Soil salinization is one of the most serious abiotic stress factors affecting plant productivity through reduction of soil water potential, decreasing the absorptive capacity of the roots for water and nutrients. A weighted meta-analysis was conducted to study the effects of arbuscular mycorrhizal fungi (AMF) inoculation in alleviating salt stress in C₃ and C₄ plants. We analyzed the salt stress influence on seven independent variables such as chlorophyll, leaf area, photosynthetic rate (Amax), stomatal conductance (Gs), transpiration rate (E), relative water content (RWC), and water use efficiency (WUE) on AMF inoculated plants. Responses were compared between C₃ and C₄ plants, AMF species, plant functional groups, level of salinity, and environmental conditions. Our results showed that AMF inoculated plants had a positive impact on gas exchange and water status under salt stress. The total chlorophyll contents of C₃ plants were higher than C₄ plants. However, C₃ plants responses regarding Gs, Amax, and E were more positive compared to C₄ plants. The increase in G_s mainly maintained E and it explains the increase in Amax and increase in E. When the two major AMF species (Rhizophagus intraradices and Funnelliformis mosseae) were considered, the effect sizes of RWC and WUE in R. intraradices were lower than those in F. mosseae indicating that F. mosseae inoculated plants performed better under salt stress. In terms of C₃ and C₄ plant photosynthetic pathways, the effect size of C₄ was lower than C₃ plants indicating that AMF inoculation more effectively alleviated salt stress in C₃ compared to C₄ plants.