Lactic Acid Bacteria Mediated Induction of Defense Enzymes To Enhance the Resistance in Tomato against Ralstonia Solanacearum Causing Bacterial Wilt

The biocontrol agent Lactic acid bacterium (LAB) was used against the bacterial wilt caused by Ralstonia solanacearum. The present investigation focuses on the role of defense related enzymes in imparting resistance to tomato plants against R. solanacearum. The LAB isolate was tested for its ability to induce the production of defense-related enzymes in treated tomato seedlings. Tomato seedlings were raised from LAB pretreated seeds, were challenge inoculated with R. solanacearum, harvested at different time intervals (0–72 h) and assayed for defense enzyme activity. The LAB treated seeds showed increase in germination percentage (6%) and seedling vigour index (259) compared with control. Treatment of tomato seedlings with LAB isolate induced a significant amount of Peroxidase (POX), Polyphenol oxidase (PPO), Phenylalanine ammonialyase (PAL), total phenolics and β-1,3-glucanase activities. The activities of PAL, POX, PPO and β-1,3-glucanase reached maximum at 24 h, 24 h, 32 h and 24 h respectively after challenge inoculation. Increased accumulation of phenolics was noticed in plants pre-treated with LAB. Native PAGE analyses of POX and PPO were carried out for the time course of enzyme activities and the isoforms of POX and PPO were examined. In field study, ten isolates of R. solanacearum treated plots yielded an average of 32.4–50 kg/m2 and LAB treated plots an average of 153.5 kg/m2. As compared to the control, LAB increased the yield by 15.3% (8.2 kg/m2) and the pathogen infected plants and pre-treated with LAB gave an average of 55% (28.3 kg/m2 compared to the infected plots). Field experiment results indicated that LAB exhibited 61.1% of disease reduction of bacterial wilt in tomato

Molecular diversity of seed-borne Fusarium species associated with maize in India

A total of 106 maize seed samples were collected from different agro-climatic regions ofIndia. Sixty-two Fusarium isolates were recovered, 90% of which were identified as Fusarium verticillioidesbased on morphological and molecular characters. Use of the tef-1alpha gene corrected/refinedthe morphological species identifications of 11 isolates, and confirmed those of the remaining isolates. Genetic diversityamong the Fusarium isolates involved multilocus fingerprinting profiles by Inter Simple Sequence Repeats (ISSR) UPGMAand tef-1 alpha gene phenetic analyses; for which, we observed no significant differences among the isolates based ongeographic origin or fumonisin production; most of the subdivision related to species. Genotyping was performed on theF. verticillioides isolates, using 12 primer sets from the fumonisin pathway, to elucidate the molecular basis of fumonisinproduction or non-production. One fumonisin-negative isolate, UOMMF-16, was unable to amplify nine of the 12 fumonisincluster genes tested. We also used the CD-ELISA method to confirm fumonisin production for our 62 Fusariumisolates. Only 15 isolates were found to be fumonisin-negative. Interestingly, genotypic characterization revealed six isolateswith various gene deletion patterns that also tested positive for the production of fumonisins via CD-ELISA. Ourfindings confirm the importance of molecular studies for species delimitation, and for observing genetic and phenotypicdiversity, among the Fusaria.</p

Efficacy of indigenous plant growth-promoting rhizobacteria and Trichoderma strains in eliciting resistance against bacterial wilt in a tomato

Bacterial wilt of tomato caused byRalstonia solanacearumis a serious threat to tomato production worldwide. For eco-friendly management of bacterial wilt of tomato, the rhizospheric microorganisms belonging to the generaBacillus(6 isolates),Brevibacillus(1 isolate),Pseudomonas(3 isolates), andTrichoderma(8 isolates) were studied for their ability to induce innate immunity in tomato, individually and in combination againstR. solanacearumin greenhouse and field studies. In laboratory studies, maximum germination percent of 93%, vigor index of 1609 was noted in seed bacterization withP. fluorescensPf3, followed by 91% germination, vigor index of 1593 in treatment withT. asperellumT8 over control. Under greenhouse conditions, protection against bacterial wilt in individual treatments with PGPRs ranged from 38 to 43% andTrichodermasp. ranged from 39 to 43% in comparison to control. In comparison to individual seed treatment, among different combinations, maximum seed germination percent of 97% was recorded with combinationP. fluorescensPf3 +T. longibrachiatumUNS11. In greenhouse studies' combination seed treatment withP. fluorescensPf3+ T. longibrachiatumUNS11 offered an impressive 62% protection against bacterial wilt over control. Similarly, under field conditions, seed treatment withP. fluorescensPf3+ T. longibrachiatumUNS11 resulted in 61% protection. The innate immunity triggered by eco-friendly seed treatment was analyzed by expression to defense-related enzymes such as peroxidase, phenylalanine ammonialyase, and polyphenol oxidase in comparison to control. This study indicated that the potential benefits of using combination treatments of beneficial microorganisms in effectively inducing resistance are possible for dual benefits of enhanced plant growth, tomato yield, and pathogen suppression

Mycosynthesis of ZnO Nanoparticles UsingTrichodermaspp. Isolated from Rhizosphere Soils and Its Synergistic Antibacterial Effect againstXanthomonas oryzaepv.oryzae

The Plant Growth Promoting Fungi (PGPF) is used as a source of biofertilizers due to their production of secondary metabolites and beneficial effects on plants. The present work is focused on the co-cultivation ofTrichodermaspp. (T. harzianum(PGT4),T. reesei(PGT5) andT. reesei(PGT13)) and the production of secondary metabolites from mono and co-culture and mycosynthesis of zinc oxide nanoparticles (ZnO NPs), which were characterized by a UV visible spectrophotometer, Powder X-ray Diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDAX) and Transmission Electron Microscope (TEM) and Selected Area (Electron) Diffraction (SAED) patterns. The fungal secondary metabolite crude was extracted from the mono and co-culture ofTrichodermaspp. And were analyzed by GC-MS, which was further subjected for antibacterial activity againstXanthomonas oryzaepv.Oryzae, the causative organism for Bacterial Leaf Blight (BLB) in rice. Our results showed that the maximum zone of inhibition was recorded from the co-culture ofTrichodermaspp. rather than mono cultures, which indicates that co-cultivation of beneficial fungi can stimulate the synthesis of novel secondary metabolites better than in monocultures. ZnO NPs were synthesized from fungal secondary metabolites of mono cultures of Trichoderma harzianum (PGT4), Trichoderma reesei (PGT5), Trichoderma reesei (PGT13) and co-culture (PGT4 + PGT5 + PGT13). These ZnO NPs were checked for antibacterial activity against Xoo, which was found to be of a dose-dependent manner. In summary, the biosynthesized ZnO NPs and secondary metabolites from co-culture ofTrichodermaspp. are ecofriendly and can be used as an alternative for chemical fertilizers in agriculture

Evaluation of biological efficacy of Trichoderma asperellum against tomato bacterial wilt caused by Ralstonia solanacearum

Abstract Bacterial wilt, caused by soilborne bacterium Ralstonia solanacearum, is one of the most severe diseases of tomato worldwide, and no successful control measures are available to date. In the present study, a sustainable alternative tool such as use of fungi from tomato rhizosphere is being utilized to combat the pathogen attack. The application of Trichoderma asperellum (T4 and T8) isolates delayed wilt development, effectively decreased the disease incidence, increased fruit yield, and improved plant growth promotion under field conditions. The T. asperellum treatment decreased the disease incidence by 51.06% (RS + T4) and 52.75% (RS + T8) in Bhoomishettihalli (BH) and 47.21% (RS + T4) and 46.83% (RS + T8) in Madanahalli (MH) plots, respectively when compared with the pathogen-treated plot in year 2014. Correspondent decreases in year 2015 were 50.69% (RS + T4) and 52.38% (RS + T8) in BH and 48.18% (RS + T4) and 49.22% (RS + T8) in MH plots. In year 2014, T. asperellum (T4 and T8) treatment enhanced the yield with 5.45 t/ha and 5.50 t/ha in BH plot and 6.66 t/ha and 6.93 t/ha in MH plot, respectively, when compared with infected plots. In year 2015, T. asperellum (T4 and T8) treatment enhanced the yield with 5.29 t/ha and 5.51 t/ha in BH plot and 5.82 t/ha and 5.66 t/ha in MH plot, respectively, when compared with infected plots. The disease control and yield enhancement were highest at T8, followed by T4. Increase in the level of peroxidase (POX), phenylalanine ammonium lyase (PAL), polyphenol oxidase (PPO), β-1,3-glucanase and total phenol activities at 12th, 10th, 14th, 12th, and 10th days, respectively, after pathogen inoculation was observed. This indicates the induction of plant resistance mechanism by T. asperellum against R. solanacearum in tomato plants under field conditions

Mycogenic Synthesis of Extracellular Zinc Oxide Nanoparticles from Xylaria acuta and Its Nanoantibiotic Potential

Purpose: The study aimed to find an effective method for fungal-mediated synthesis of zinc oxide nanoparticles using endophytic fungal extracts and to evaluate the efficiency of synthesized ZnO NPs as antimicrobial and anticancerous agents. Methods: Zinc oxide nanoparticles (ZnO NPs) were produced from zinc nitrate hexahydrate with fungal filtrate by the combustion method. The spectroscopy and microscopy techniques, such as ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), and transmission electron microscopy (TEM) with selected area electron diffraction (SAED), were used to characterize the obtained product. Antibacterial activity on Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) samples was tested by broth microplate dilution technique. ZnO NPs antifungal activity was determined against plant pathogenic and regular contaminating fungi using the food-poison method. The anticancerous assay of the synthesized ZnO NPs was also investigated by cell uptake, MTT assay, and apoptosis assay. Results: The fungal synthesized ZnO NPs were pure, mainly hexagonal in shape and size range of 34-55 nm. The biosynthesized ZnO NPs could proficiently inhibit both Gram-positive and Gram-negative bacteria. ZnO NPs synthesized from fungal extract exhibited antifungal activity in a dose-dependent manner with a high percentage of mycelial inhibition. The cell uptake analysis of ZnO NPs suggests that a significant amount of ZnO NPs (1 mu g/mL) was internalized without disturbing cancer cells' morphology. As a result, the synthesized ZnO NPs showed significant anticancer activity against cancer cells at 1 mu g/mL concentration. Conclusion: This fungus-mediated synthesis of ZnO NPs is a simple, eco-friendly, and non-toxic method. Our results show that the synthesized ZnO NPs are an excellent novel antimicrobial and anticancer agent. Further studies are required to understand the mechanism of the antimicrobial, anticancerous action of ZnO NPs and their possible genotoxicity

Biosynthesis of Zinc Oxide Nanoparticles Using Leaf Extract of Passiflora subpeltata: Characterization and Antibacterial Activity Against Escherichia coli Isolated from Poultry Faeces

The current study was undertaken to investigate the antibacterial (against molecular characterized E. coli isolated from poultry faeces) potential of biosynthesized zinc oxide nanoparticles (ZnO-NPs) from Passiflora subpeltata Ortega aqueous leaf extract. The biosynthesized nanoparticles were subjected to physico-chemical characterization to study shape, size and purity by UV-Vis spectroscopy, X-Ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscopy (TEM). The molecular identification of isolated E. coli from faeces samples was carried out by using 16-23s rRNA primers. The results of the physico-chemical characterization revealed that the biosynthesized nanoparticles were of 93.7% purity with an average size between 45 and 50 nm. The ZnO-NPs offered significant inhibition against the isolated Gram-negative E. coli with MIC at 62.5 mu g mL(-1) concentration. The antibacterial potential of ZnO NPs against E. coli has also been investigated by the cell viability test, and further the effects of ZnO NPs on bacterial morphological structures was analysed by SEM and TEM

Cinnamomum verum Bark Extract Mediated Green Synthesis of ZnO Nanoparticles and Their Antibacterial Potentiality

Cinnamomum verum plant extract mediated propellant chemistry route was used for the green synthesis of zinc oxide nanoparticles. Prepared samples were confirmed for their nano regime using advanced characterization techniques such as powder X-ray diffraction and microscopic techniques such as scanning electron microscopy and transmission electron microscopy. The energy band gap of the green synthesized zinc oxide (ZnO)-nanoparticles (NPs) were found between 3.25-3.28 eV. Fourier transmission infrared spectroscopy shows the presence of Zn-O bond within the wave number of 500 cm(-1). SEM images show the specific agglomeration of particles which was also confirmed by TEM studies. The green synthesized ZnO-NPs inhibited the growth of Escherichia coli and Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 125 mu g mL(-1) and 62.5 mu g mL(-1), respectively. The results indicate the prepared ZnO-NPs can be used as a potential antimicrobial agent against harmful pathogens