Formulations of synergistic microbial consortia for enhanced systemic resistance against Fusarium wilt in cumin.

The study aimed to understand the dynamic interplay between plants and their associated microbes to develop an efficient microbial consortium for managing Fusarium wilt of cumin. A total of 601 rhizospheric and endophytic bacteria and fungi were screened for antagonistic activity against Fusarium oxysporum f.sp. cumini (Foc). Subsequently, ten bacteria and ten fungi were selected for characterizing their growth promotion traits and ability to withstand abiotic stress. Furthermore, a pot experiment was conducted to evaluate the bioefficacy of promising biocontrol isolates-1F, 16B, 31B, and 223B in mono and consortium mode, focusing on disease severity, plant growth, and defense responses in cumin challenged with Foc. Promising isolates were identified as Trichoderma atrobruneum 15F, Pseudomonas sp. 2B, Bacillus amyloliquefaciens 9B, and Bacillus velezensis 32B. In planta, results revealed that cumin plants treated with consortia of 15F, 2B, 9B, and 32B showed highest percent disease control (76.35%) in pot experiment. Consortia of biocontrol agents significantly enhanced production of secondary metabolites and activation of antioxidant-defense enzymes compared to individual strain. Moreover, consortium treatments effectively reduced electrolyte leakage over the individual strain and positive control. The four-microbe consortium significantly enhanced chlorophyll (~ 2.74-fold), carotenoid content (~ 2.14-fold), plant height (~ 1.8-fold), dry weight (~ 1.96-fold), and seed yield (~ 19-fold) compared to positive control in pot experiment. Similarly, four microbe consortia showed highest percent disease control (72.2%) over the positive control in field trial. Moreover, plant growth, biomass, yield, and yield attributes of cumin were also significantly increased in field trial over the positive control as well as negative control.

Physicochemical and bioactive constituents, microbial counts, and color components of spray-dried Syzygium cumini L. pulp powder stored in different packaging materials under two controlled environmental conditions.

Currently, the demand for functional food items that impart health benefits has been rising. Blackberry (Syzygium cumini L.) fruit has high anthocyanin content and other functional attributes. However, this seasonal fruit is highly perishable, and a large proportion of it goes unharvested and wasted worldwide. Spray drying of the fruit pulp can impart improved shelf life, ensuring long-term availability for consumers to exploit its health benefits. The storage quality varies according to the type of packaging material and the storage environment. Therefore, in this study, the shelf life span of the spray-dried Syzygium cumini L. pulp powder (SSCPP) was investigated during 6 months of storage under three types of packaging materials (i.e., polystyrene, metalized polyester, and 4-ply laminates) in a low-temperature environmental (LTE) and at ambient environmental conditions. The physicochemical stability of bioactive principles (TPC and TAC), microbial counts, and color components were analyzed at 0, 2, 4, and 6 months of storage. There was a significant gradual loss of dispersibility and solubility with an increase in flowability, bulk density, and wettability during the entire storage period for all three packaging materials. The TSS, pH, TPC, TAC, and microbial counts decreased in the SSCPP both at ambient and LTE conditions during the study. Among all the packaging materials, the 4-ply laminate was found to be the most appropriate and safe for storage of spray-dried SCPP at LTE conditions.

Effect of mineral phosphates on growth and nitrogen fixation of diazotrophic cyanobacteria Anabaena variabilis and Westiellopsis prolifica.

The nitrogen fixing cyanobacterial strains namely Anabaena variabilis (Nostocales, Nostocaceae) and Westiellopsis prolifica (Nostocales, Hapalosiphonaceae) were evaluated for their nitrogen fixation and growth potential in response to different concentrations (10, 20 and 30 mg P) of the alternate insoluble P-sources Mussorie Rock Phosphate and Tricalcium Phosphate. Distinct and significant intergeneric differences were observed with respect to nitrogen fixation measured as Acetylene Reduction Activity (ARA) and growth potential as soluble proteins, total carbohydrate content, dry weight and total chlorophyll content in response to different concentrations of Mussorie Rock Phosphate and Tricalcium Phosphate. Both the strains showed higher soluble protein content at 20 mg P (Mussorie Rock Phosphate) that increased with time of incubation in A. variabilis. Both cyanobacteria recorded maximum Acetylene Reduction Activity at 20 mg P (Tricalcium Phosphate) followed by activity in presence of soluble phosphate (K2HPO4). The mean activity at all concentrations of insoluble phosphate (Mussorie Rock Phosphate and Tricalcium Phosphate) was more than in the presence of soluble phosphate.

Effect of mineral phosphate solubilization on biological nitrogen fixation by diazotrophic cyanobacteria.

The ability of two diazotrophic cyanobacteria Westiellopsis prolifica and Anabaena variabilis were examined to solubilize extracellular insoluble tricalcium phosphate (TCP) and Mussorie rock phosphate (MRP). The two strains exhibited a differential response to insoluble forms of phosphorus used. W. prolifica showed better growth in presence of MRP while A. variabilis proliferated better in presence of TCP. Biological nitrogen fixation measured in terms of acetylene reduction (AR) activity showed significant variation among the concentrations of TCP or MRP and time of incubation. W. prolifica and A. variabilis showed maximum AR activity on 14 and 21 days of incubation respectively. In general AR activity in presence of MRP was always less than that in presence of TCP at all concentrations. Among the two cyanobacteria A. variabilis was best in terms of P-solubilization and nitrogen fixation and TCP (20 mg P l(-1)) was the best source of insoluble P rather than MRP or K(2)HPO(4).