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Biofabrication of metal nanoparticles is a cost-effective, one-step and ecofriendly technique. Cell filtrate of an endophytic fungus isolated from Nyctanthes arbor-tristis was challenged with 1 mM solution of AgNO3 for the silver nanoparticles (AgNPs) synthesis. A reduction of silver ions into AgNPs was observed by surface plasmon resonance at absorption maxima 422 nm. The average size of AgNPs was 35.05 nm. The maximum inhibition zones by AgNPs were 14 mm each against E. coli and Pseudomonas aeruginosa compared to AgNO3 solution used as control (10 mm and 9 mm). The fungus was identified as Phomopsis helianthi by the sequencing of ITS region of rDNA. This experiment demonstrates a single-step and ecofriendly method for biosynthesis of AgNPs and their usage as an antimicrobial agent. more...

Seed-vectored endophytes internally colonize plant seeds and remain without eliciting disease symptoms. Microbes are carried by seeds generation after generation to benefit the host during and following seed germination. Seed-vectored endophytes have been poorly investigated and research targeted at understanding their biology will have immense applications in agriculture and horticulture. Some reports are available on the roles of seed endophytes in plant growth promotion via nutrient acquisition and biocontrol of soil borne diseases, but mechanisms of interaction at the endophyte-host interface, especially during seed germination and seedling establishment, have not been explored adequately. The present paper is intended to review the role of seed vectored endophytes in seed germination, seedlings development and in developing the rhizosphere community. The mechanisms of interaction and movement of seed inhabiting endophytic bacteria are explained with the help of pictorial models. more...

An endophytic fungus isolated from photosynthetic root of Tinospora cordifolia Miers. was identified as Pseudofusicoccum adansoniae with 100% 18S ITS rRNA partial gene sequence similarity (accession JX951181). The fungus exhibited amylase, lipase and protease activities and was also able to assimilate the galactose, glucose, fructose, lactose and maltose along with l-arginine and alanine. In addition to siderophore production, the fungus was found to be tolerant against various concentrations of NO2−, NO3− and NaCl. The maximum biomass and metabolite yield were observed at pH range 5.4–7.0, whereas yield of secondary metabolites was highest in potato dextrose broth (36.66 ± 0.33 mg/100 ml) extracted through ethyl acetate (EtOAc). Interestingly, metabolites extracted through ethyl acetate from PDB and MEB grown cultures were found to be active against all 8 human bacterial pathogens used in this study. The isolation and characterization of P. adansoniae done in this experiment are the initial steps which pave the way for purified isolation of bioactive compounds and enzymes of immense use. more...

Leersia oryzoides, a wild relative of rice (Oryza sativa), may carry potential seed-borne bacterial endophytes which could be used to enhance growth of rice. We hypothesized that seed-associated bacteria from L. oryzoides would be compatible with rice and promote seedling growth, development, and survival. We isolated bacteria from seed of L. oryzoides and checked compatibility with rice as well as Bermuda grass seeds for seedling growth promotion. Internal colonisation of bacteria into root cells was observed by ROS staining and microscopic observation. Growth promoting bacteria were evaluated for IAA production, phosphate solubilization and antifungal activities. Overall, ten bacteria were found to be growth promoting in rice seedlings with effects including restoration of root gravitropic response, increased root and shoot growth, and stimulation of root hair formation. All bacteria were identified by 16S rDNA sequencing. Six bacteria were found to become intracellular in root parenchyma and root hairs in rice and in Bermuda grass seedlings. Six bacteria were able to produce IAA in LB broth with highest (47.06 ± 1.99 μg ml−1) by LTE3 (Pantoea hericii). Nine isolates solubilized phosphate and inhibited at least one soil borne fungal pathogen. Seed bacteria of L. oryzoides are compatible with rice. Many of these bacteria become intracellular, induce root gravitropic response, increase root and shoot growth, and stimulate root hair formation in both rice and Bermuda grass seedlings. Presence of bacteria protects seedlings from soil pathogens during seedling establishment. This research suggests that bioprospecting microbes on near relatives of rice and other crop plants may be a viable strategy to obtain microbes to improve cultivation of crops. more...

A total of 1,897 isolates of endophytic fungi from Madhuca indica Gmel., representing 40 morphologically distinct fungal taxa were obtained from 2,700 segments of stem, bark and leaf from three different locations (Loc 1, Loc 2 and Loc 3) in Uttar Pradesh, India. Out of 40 taxa, 28 were identified microscopically and the remaining 12 by molecular methods. Coelomycetes (62.41 %) were the most prevalent fungal group followed by hyphomycetes (28.89 %) and ascomycetes (8.70 %). Colonisation frequency (CF) was greater in stem (82.55 %) than in leaf (65.00 %) and bark (63.22 %). Due to the dominance of a few taxa, species richness and Shannon and Simpson diversity indices were lower in stem than in leaf and bark at each location. Interestingly, less rainfall and lower temperatures disfavoured the overall colonisation of fungal endophytes at Loc 2. The stem samples from all locations were very similar in their endophytic composition, whereas bark and leaf samples showed differences. The dominant endophytic fungi isolated were Phomopsis sp. 1 (9.185 %), and Colletotrichum gloeosporioides (7.00 %). Principal component analysis showed 55 % tissue specificity with 51.08 % maximum variance. Antibacterial activity revealed that 58.33 % endophytic fungi were active against at least one or more bacterial pathogens, whereas the crude extract of five endophytic fungi inhibited the growth of five or more than five (50 %) of the pathogens tested. This report illustrates the value of having an adequate sample size from different tissues and different locations for species and chemical diversity in search of novel natural products. more...

A study was conducted for isolation, identification and antibacterial potential of fungal endophytes of Adenocalymma alliaceum Miers., (Bignoniaceae), a medicinal shrub vine plant which has long history for its usages in curing various disorders. A total of 149 isolates of endophytic fungi representing 17 fungal taxa were obtained from 270 segments (90 from each stem, leaf and petiole) of this plant. Hyphomycetes (77.85%) were the most prevalent, followed by Ascomycetes (8.05%) and Coelomycetes (4.03%) respectively. A considerable amount of fungal isolates was kept under (10.07%) Mycelia-Sterilia (MS). Leaf harboured maximum colonization of endophytic fungi (72.22%) which was greater than stem (67.78%) and petiole (25.54%). The Jc similarity index was maximum (0.619) between stem vs leaf followed by leaf vs petiole (0.571) and stem vs petiole (0.428). The dominant endophytic fungi were Alternaria alternata, Aspergillus niger, Stenella agalis, Fusarium oxysporum, Curvularia lunata and Fusarium roseum. Among twelve endophytic fungi tested for antibacterial activity, crude extracts of nine endophytic fungi (75%), showed antibacterial potential against one or more clinical human pathogens. Alternaria alternata, Curvularia lunata, Penicillium sp. and Chaetomium globosum exhibited significant antibacterial activity against 4 of 5 tested pathogens, showing broad spectrum activity. This investigation explains the value of sampling from different tissues of a host plant for the greater species diversity, and additionally, the antibacterial screening of some endophytic fungi from this specific medicinal plant may represent a unique source for many of the useful antibacterial compounds. more...

This study was performed to analyse the impact of leaf segment size and culture media on isolation and diversity of endophytic fungi from Madhuca longifolia with enzyme production potential. Total 14 taxa of endophytic fungi were recovered, dominated by Colletotrichum gloeosporioides, Corynespora and Macrophoma respectively. Reduction in leaf segment size showed increased isolation rate and significantly changed the diversity to all culture media. On potato dextrose agar 153 isolates were recovered with minimum isolation rate and diversity (1.20 isolates/cm2, Shannon index 1.43) to larger size segments (T1), followed by medium size segments (T2) (1.95 isolates/cm2, Shannon index 1.78) and maximum to small size segments (T3) (4.50 isolates/cm2, Shannon 1.89). On malt extract agar 145 isolates were recovered in which large size segments showed minimum isolation rate and diversity (1.30 isolates/cm2, Shannon of 1.33) followed by medium size (isolation rate 1.95 isolates/cm2, Shannon of 1.55) and maximum to small size segments (isolation rate 4.0 isolates/cm2, Shannon of 1.96). On water agar, 108 isolates were recovered with similar trends of isolation rate and diversity to large size (0.65 isolates/cm2, Shannon of 0.27) followed by medium size (isolation rate 1.40 isolates/cm2, Shannon of 1.42) and maximum to small size segments (3.35 isolates/cm2, Shannon of 1.59). This study revealed significantly that smaller leaf segment was most suitable size that gives real measures of isolation rate and diversity. Interestingly, of 24 endophytic fungi evaluated for enzyme activity, 18 were found positive to amylase, 9 to cellulase, 5 to pectinase and 14 to urease, respectively. more...

Seventeen isolates of Pseudomonas fluo-rescens (Pf) were examined for growth promotion and the induction of systemic resistance against early blight disease of tomato. A noticeable in-crease in shoot and root length was observed in plants treated with P. fluorescens. However, the root development was reduced by a combination of P. fluorescens and Alternaria alternata (A. alter-nata). P. fluorescens isolates systemically induced resistance against early blight of tomato caused by A. alternata and reduced (approx.18–42%) the dis-ease significantly. All the isolates of P. fluorescens produced salicylic acid (SA) in King's B (KB) broth and induced its accumulation in tomato leaf within 24 h of bacterial inoculation. SA levels were signifi-cantly increased in plants treated with bacteria compared to the split control from one to five days following inoculation. Low SA concentration (0.1–0.5 mg/ml) did not inhibit mycelial growth of A. alternata in vitro, contrary to inhibition at high concentrations. The exogenously applied SA first accumulates in host tissues and induces resistance, however, endogenous SA accumulation in plant tissue is considered to be involved in induced sys-temic resistance to early blight disease of tomato caused by A. alternata. more...

During present study, 513 isolates were recovered from 15 different experimental sites. For fungal recovery, PDA medium proved better over Czapek's dox agar medium (CDA), while Waksman dilution method showed higher isolates recovery than Warcup's soil plate method. Thirty filamentous fungi were recovered of which Aspergillus, Alternaria, Cladosporium, and Fusarium were dominant. Aspergillus niger and A. fumigatus showed a high frequency of occurrence and were isolated @ 80 x103 CFU/g and 47x 103 CFU/g, respectively from dry, moist and humid soil samples, while Penicillium notatum (37x103 CFU/g), Nigrospora oryzae (30 x103 CFU/g), Rhizopus nigricans (32x103 CFU/g), Trichoderma viride (24x103 CFU/g) were isolated with moderate frequency. Fifty three isolates were recovered from site 10 (Agriculture field, BHU) which was highest whereas, 12 isolates were recovered from site 1 (Cantt Railways Station). Consequently, the site 10 had the maximum CFU value (53x103 CFU/g) whereas site 1 had the lowest (12 x103 CFU/g). A higher percentage of soil fungi isolated have preferred the acidic pH range. Mean of fungal isolates was higher in moist (37.60), followed by humid (34.50) and dry (30.20) conditions. Bray-Curtis cluster analysis was done to understand that several variables are responsible for the diversity and occurrence of soil fungi. more...