Plant growth promoting rhizobacteria (PGPR) are the rhizosphere bacteria that may be utilized to augment plant growth and suppress plant diseases. The objectives of this study were to identify and characterize PGPR indigenous to cucumber rhizosphere in Bangladesh, and to evaluate their ability to suppress Phytophthora crown rot in cucumber. A total of sixty six isolates were isolated, out of which ten (PPB1, PPB2, PPB3, PPB4, PPB5, PPB8, PPB9, PPB10, PPB11 and PPB12) were selected based on their in vitro plant growth promoting attributes and antagonism of phytopathogens. Phylogenetic analysis of 16S rRNA sequences identified these isolates as new strains of Pseudomonas stutzeri, Bacillus subtilis, Stenotrophomonas maltophilia and B. amyloliquefaciens. The selected isolates produced high levels (26.78 to 51.28 μg mL−1) of indole-3-acetic acid, while significant acetylene reduction activities (1.79 to 4.9 µmole C2H4 mg-1 protein h-1) were observed in eight isolates. Cucumber plants grown from seeds that were treated with these PGPR strains displayed significantly higher levels of germination, seedling vigor, growth, and N content in root and shoot tissue compared to non-treated control plants. All selected isolates were able to successfully colonize the cucumber roots. Moreover, treating cucumber seeds with these isolates significantly suppressed Phytophthora crown rot caused by Phytophthora capsici, and characteristic morphological alterations in Ph. capsici hyphae that grew towards PGPR colonies were observed. Since these PGPR inoculants exhibited multiple traits beneficial to the host plants, they may be applied in the development of new, safe, and effective seed treatments as an alternative to chemical fungicides.

Amaranth has two morphological types described as red and green morphs. Previous studies have extensively characterised red morph amaranth regarding both morphological and chemical properties including antioxidant activity, antioxidant phytochemical profile, mineral content and proximate composition. However, there is scarce information concerning green morph amaranth. Hence, the present study evaluated 12 green morph genotypes for proximate composition, antioxidant activity, antioxidant pigments, minerals, and phytochemicals. Green morph amaranth was found to contain abundant carbohydrates, dietary fiber and protein. We found notable levels of inorganic minerals including potassium, calcium, magnesium, iron, manganese, copper and zinc. Antioxidant capacity quantified as free radical quenching capacity varied between 27 and 48 μg g⁻¹ Trolox equivalents. We additionally quantified antioxidants, including total phenolics, total flavonoid equivalents and vitamin C, as well as the antioxidant pigments carotenoids, chlorophylls and betalains. These data indicated that four green morph genotypes could be considered as enriched in their antioxidant profiles. Green morph amaranth could be a potential source of nutritional components and antioxidant phytochemicals in the human diet providing opportunities to address mineral nutrient deficiencies and provide an antioxidant rich food

Arabidopsis thaliana grown in soil amended with barley grain inocula of Penicillium simplicissimum GP17-2 or receiving root treatment with its culture filtrate (CF) exhibited clear resistance to Pseudomonas syringae pv. tomato DC3000 (Pst). To assess the contribution of different defense pathways, Arabidopsis genotypes implicated in salicylic acid (SA) signaling expressing the NahG transgene or carrying disruption in NPR1 (npr1), jasmonic acid (JA) signaling (jar1) and ethylene (ET) signaling (ein2) were tested. All genotypes screened were protected by GP17-2 or its CF. However, the level of protection was significantly lower in NahG and npr1 plants than it was in similarly treated wild-type plants, indicating that the SA signaling pathway makes a minor contribution to the GP17-2-mediated resistance and is insufficient for a full response. Examination of local and systemic gene expression revealed that GP17-2 and its CF modulate the expression of genes involved in both the SA and JA/ET signaling pathways. Subsequent challenge of GP17-2-colonized plants with Pst was accompanied by direct activation of SA-inducible PR-2 and PR-5 genes as well as potentiated expression of the JA-inducible Vsp gene. In contrast, CF-treated plants infected with Pst exhibited elevated expression of most defense-related genes (PR-1, PR-2, PR-5, PDF1.2 and Hel) studied. Moreover, an initial elevation of SA responses was followed by late induction of JA responses during Pst infection of induced systemic resistance (ISR)-expressing plants. In conclusion, we hypothesize the involvement of multiple defense mechanisms leading to an ISR of Arabidopsis by GP17-2.

Sclerotinia sclerotiorum (Lib.) de Bary is a broad host-range fungus that infects an inclusive array of plant species and afflicts significant yield losses globally. Despite being a notorious pathogen, it has an uncomplicated life cycle consisting of either basal infection from myceliogenically germinated sclerotia or aerial infection from ascospores of carpogenically germinated sclerotia. This fungus is unique among necrotrophic pathogens in that it inevitably colonizes aging tissues to initiate an infection, where a saprophytic stage follows the pathogenic phase. The release of cell wall-degrading enzymes, oxalic acid, and effector proteins are considered critical virulence factors necessary for the effective pathogenesis of S. sclerotiorum. Nevertheless, the molecular basis of S. sclerotiorum pathogenesis is still imprecise and remains a topic of continuing research. Previous comprehensive sequencing of the S. sclerotiorum genome has revealed new insights into its genome organization and provided a deeper comprehension of the sophisticated processes involved in its growth, development, and virulence. This review focuses on the genetic and genomic aspects of fungal biology and molecular pathogenicity to summarize current knowledge of the processes utilized by S. sclerotiorum to parasitize its hosts. Understanding the molecular mechanisms regulating the infection process of S. sclerotiorum will contribute to devising strategies for preventing infections caused by this destructive pathogen.

Climate change is increasingly conceded as a significant menace to global agricultural productivity, with plant diseases emerging as a critical challenge in this context. Plant diseases can result in an annual reduction of approximately US$220 billion in agricultural productivity, impacting global economies and socio-economic stability. To address these challenges, it is crucial to explore the intricate relationship between climatic variables and the occurrence, intensity, and geographic distribution of plant diseases, highlighting how shifts in temperature, CO₂ levels, and precipitation patterns exacerbate pathogen virulence and alter disease dynamics. This review examines the historical and projected impacts of climate change on vulnerable crops and regions, emphasizing the heightened risk to food security. The molecular basis of climate-modulated plant defense mechanisms and pathogen virulence is dissected, offering insights into the underlying biological processes that govern these interactions. In response to this escalating threat, we discuss climate-informed plant disease management strategies, including early warning systems, adaptive surveillance, and the development of resilient crops through biotechnological advancements such as genetic engineering, gene silencing, and genome editing. Additionally, we explore the role of resource-saving technologies and precision agriculture in mitigating the adverse repercussions of climate change on plant health. The review concludes with an exploration of critical research needs and future perspectives, underscoring the urgent need for interdisciplinary approaches to safeguard sustainable agricultural productivity in a rapidly changing climate.