Plant growth-promoting rhizobacteria (PGPR) are a group of root-associated beneficial bacteria emerging as one of the powerful agents in sustainable plant disease management. Among the PGPR, Bacillus sp. has become a popular biocontrol agent for controlling pests and the diseases of several crops of agricultural and horticultural importance. Understanding the molecular basis of the plant growth-promoting and biocontrol abilities of Bacillus spp. will allow us to develop multifunctional microbial consortia for sustainable agriculture. In our study, we attempted to unravel the genome complexity of the potential biocontrol agent Bacillus subtilis Bbv57 (isolated from the betelvine’s rhizosphere), available at TNAU, Coimbatore. A WGS analysis generated 26 million reads, and a de novo assembly resulted in the generation of 4,302,465 bp genome of Bacillus subtilis Bbv57 containing 4363 coding sequences (CDS), of which 4281 were functionally annotated. An analysis of 16S rRNA revealed its 100% identity to Bacillus subtilis IAM 12118. A detailed data analysis identified the presence of >100 CAZymes and nine gene clusters involved in the production of secondary metabolites that exhibited antimicrobial properties. Further, Bbv57 was found to harbor 282 unique genes in comparison with 19 other Bacillus strains, requiring further exploration.

Climate change is an emerging threat to global food and nutritional security. The tropical fruits such as mango, bananas, passionfruit, custard apples, and papaya are highly sensitive to weather changes especially; changes of monsoon onset and elevated temperature are influencing crop growth and production. There is a need for more specific studies concerning individual crops and regional variations. Long-term effects and interactions of weather parameters and increased concentration of greenhouse gases, especially carbon dioxide, with phenological stages of the plant, pests, and diseases remain understudied, while adaptation strategies require further exploration for comprehensive understanding and effective mitigation. Few researchers have addressed the issues on the effect of climate change on tropical fruits. This paper focuses on the impact of abiotic (temperature, rainfall, humidity, wind speed, evaporation, carbon dioxide concentration) and biotic (pest and pathogens dynamics) factors affecting the fruit crop ecosystem. These factors influence flowering, pollination, fruit set, fruit yield and quality. This review paper will help develop adaptive strategies, policy interventions and technological innovations aimed at mitigating the adverse effects of climate change on tropical fruit production and safeguarding global food and nutritional security.

The efficacy of plant growth-promoting rhizobacteria (PGPR) was tested against the powdery mildew of grapevine caused by Uncinula necator (Schw.) Burn. Foliar application of talc-based Pseudomonas fluorescens strain Pf1 at 2% significantly reduced the incidence of powdery mildew under glasshouse conditions through the induction of defense gene products such as peroxidase (PO), polyphenol oxidase (PPO) and chitinase. The isoforms of peroxidases were observed in Native Poly acrylamide gel electrophorosis (PAGE). Plants challenged with Pf1 against U. necator expressed three isoforms of peroxidase (PO1 – PO3) while only one isoform of PO was expressed in control with less intensity. The expression pattern of PPO showed that there was no extra isoform except the level of induction in Pf1-treatment against the powdery mildew pathogen. Native gel electrophoresis detected four isoforms of chitinase in plants challenged with Pf1.

Horse gram is one of the lesser-known beans widely grown in India. One hundred and twenty-three homozygous horse gram mutants were screened for powdery mildew (PM) disease resistance using the grade 0 to 4. The mutants were grouped based on the disease level of 0 to 2 (resistant) and susceptible (3 to 4). The PM altered the chlorophyll fluorescence (a/b ratio), maturity duration, and yield attributing traits. The yield loss ranged from 4.55% to 72.66%. After affirming the resistance level, the resistant mutant (RM) with minimum yield loss (scale:0) and the susceptible mutant (SM) with maximum loss (scale:4) were used for metabolomic analysis through GC-MS. PM infection induced expression of 66 metabolites representing 32 functional classes. The number of unique classes in RM and SM was 13 and 11, respectively, while eight were common. A fold change in the common metabolites indicated an enhanced accumulation of amine, alcohol, and ester in RM. Along with pathogen-induced defensive metabolites, RM produced silane and fluorene, whose biological significance in disease resistance is unknown. Though SM expressed defence-related bio-molecules, it failed to yield better.