Nanda Nath Saikia College

Ensuring plant resilience is crucial for maintaining global food security amidst a changing climate. Leveraging the multitude of microorganisms in different environmental conditions appears to be a promising and sustainable approach to boosting agricultural productivity. However, understanding the legacy of microbial bioinoculants in agroecosystems remains a challenging issue, thereby hampering their widespread applicability and acceptance. This review offers an in-depth insight into the intricacies of designing effective bioinoculants, orchestrated by an understanding of the ecological contexts that drive their success. Furthermore, this article emphasizes the importance of adopting a holistic approach to designing effective bioinoculants, thereby enhancing their application in agriculture.

Tomato is a globally important crop and model for plant-pathogen studies, with bacterial wilt caused by Ralstonia solanacearum posing a major threat. Understanding metabolic changes in resistant and susceptible cultivars during infection is vital. This study investigated the metabolic responses of resistant (Hawaii 7996) and susceptible (Marmande) tomato cultivars under R. solanacearum infection, identified key metabolites and defense pathways, and compared metabolite accumulation using high-resolution mass spectrometry. Liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS) was used to analyze root samples at 6 days post-inoculation. Data processed in MetaboAnalyst 6.0 identified differentially accumulated metabolites through multivariate analysis, heatmaps, and volcano plots. Pathway and chemical superclass enrichment analyses revealed distinct responses between cultivars. The resistant cultivar showed markedly higher abundance of defense-related metabolites in pathways such as glutathione metabolism, tropane/piperidine/pyridine alkaloid biosynthesis, phenylalanine metabolism, terpenoid backbone biosynthesis, and sesquiterpenoid/triterpenoid biosynthesis, indicating a robust defense response. In contrast, the susceptible cultivar exhibited fewer changes in these pathways, suggesting a weaker defense. Baseline differences were also observed, with the resistant cultivar displaying elevated levels of certain defense-associated metabolites even without infection. Overall, the findings clearly demonstrate that resistance in Hawaii 7996 is driven by a strong activation and maintenance of key defense-related metabolic pathways, whereas Marmande fails to initiate comparable metabolic reprogramming under infection. These results provide direct metabolomic evidence linked to bacterial wilt resistance and identify specific metabolites and pathways that may serve as promising biochemical targets for breeding disease-resilient tomato cultivars.

There is a consistent increase in persistent organic pollutants and co-contaminants across diverse ecosystems. The polychlorinated biphenyls, polycyclic aromatic hydrocarbons and organochlorine pesticides along with heavy metals pose serious threats to our ecosystem and environment. Use of conventional physical and chemical decontamination technologies of persistent organic pollutant removal is often discouraged due to their operational complexities and potential environmental hazards. The pollutant removing potential of certain plants has been attributed to the assemblance of putative microbial populations residing in their inner tissues, popularly known as the endophytes. The current review addresses the potential of endophyte microbial mutualists as significant contributors in phytoremediation. The intrinsic metabolic machineries of the endophytic fungal cell factories accelerate the host plant’s mechanism in pollutant decontamination. Notwithstanding significant progress in the field, a comprehensive understanding of host-endophyte interaction during pollutant removal is still challenging. In this context, the current review has been designed to study the mechanistic interactions of endophyte fungi-mediated phytoremediation of persistent organic pollutants and co-contaminants. The review delineates the characteristics of various persistent organic pollutants, provides a concise overview of endophytic and arbuscular mycorrhizal fungi, and elucidates their essential mechanisms in augmenting the phytoremediation of persistent organic pollutants and associated contaminants. The recent update discusses technological interventions in host-fungal endophyte interactions that enhance phytoremediation efficiency and highlights potential in future research approaches.

Nanofertilizers (NFs) represent an emerging strategy to improve nutrient use efficiency (NUE) and minimize nutrient losses in agriculture. Recent advances have focused on composite nanofertilizers capable of delivering multiple nutrients simultaneously. In this study, three combinatorial nanofertilizers were synthesized by impregnating macronutrients into Hydroxyapatite (HNF), Zeolite (ZNF), and Chitosan (CNF) nanoparticles. Their physicochemical characteristics including swelling ratio, water absorption and retention capacity, and nutrient leaching patterns were systematically evaluated. In addition, their effects on rice growth, biochemical responses, and soil nutrient availability were investigated under pot experiments. The results demonstrated that nutrient loading within porous nanostructures produced spongy, slow-release formulations. ZNF exhibited the highest swelling ratio (3.2%), whereas HNF achieved the greatest water absorption capacity (85%). Water retention studies revealed that ZNF was initially most effective, though its performance declined faster compared to HNF and CNF, which showed more stable retention over 15 days. All nanofertilizer treatments enhanced the leaching of Fe, K, Zn, NO₃⁻, PO₄³⁻, and Mg relative to the control, with ZNF exhibiting the highest leaching activity. Moreover, ZNF treatment consistently induced greater peroxidase POD activity in both leaves and roots. Growth analyses indicated that nanofertilizer application significantly improved plant height, root length, leaf number, tiller count, and 1000-grain weight compared to the control (CK). Among treatments, ZNF outperformed HNF and CNF, leading to higher grain protein and carbohydrate content. The findings of the present study suggest that combinatorial nanofertilizers, particularly ZNF, provide an effective and sustainable approach to enhancing rice productivity and nutritional quality.

The increasing global demand for maintaining sustainable agriculture has focused on the critical role played by endophytic entomopathogenic fungi as dual-purpose microbial agents facilitating plant growth promotion and pest management. Endophytic entomopathogenic fungi as natural endosymbionts, provide multifaceted benefits, such as improving plant growth and nutrient uptake, enhancing tolerance to biotic and abiotic stresses, and protecting the crops against devastating insect pests, pathogens, nematodes, and weeds. Addressing the potential of endophytic entomopathogenic fungi in agriculture has eventually reduced the dependence on toxic agrochemicals, thereby assists to adopt key alarms of environmental safety and agricultural sustainability. Direct application of this category of fungi involves seed treatment, soil inoculation, and foliar sprays, resulting enhancement in plant endosphere colonization, assisting in optimum plant protection and growth promotion. Indirect applications include the potential use of bioformulations, thereby reducing the reliance on toxic chemical fertilizers and pesticides. Customized strategies for integrating entomopathogenic fungi into sustainable pest and disease management frameworks must be generated to boost their use efficiency under field evaluations. These strategies must ensure that the fungi are compatible with other biocontrol agents and recommended dosages of agrochemicals. The integration of advanced technologies, including the genetic engineering, myconanoformulations, artificial intelligence, and the internet of things, alongside Fuzzy logics, has recently revolutionized the strategic advancements in entomopathogenic research for sustainable plant growth promotion and crop protection, leading to the development of climate-smart agriculture.