Search

Endophytic fungal isolates Hypocrea lixii F3ST1 and Beauveria bassiana G1LU3 were evaluated for their potential to endophytically colonize and induce active compounds in Phaseolus vulgaris, as a defense mechanism against pea leafminer (Liriomyza huidobrensis) and fall armyworm (Spodoptera frugiperda). Endophytic colonization was achieved through seed inoculation with the volatile emissions from P. vulgaris plants being analyzed using GC-MS. The crude extracts of P. vulgaris obtained using methanol and dichloromethane were assayed against leafminer and fall armyworm larvae using leaf dipping and topical application, respectively. The two isolates successfully colonized the entire host plant (roots, stems, and leaves) with significant variation (p < 0.001) between fungal isolates and the controls. The results showed qualitative differences in the volatile profiles between the control plants, endophytically colonized and insect-damaged plants attributed to fungal inoculation and leafminer damage. The crude methanol extracts significantly reduced the percentage pupation of 2nd instar leafminer larvae (p < 0.001) and adult-flies emergence (p < 0.05). The survival of the 1st instar fall armyworm larvae was also significantly reduced (p < 0.001) compared to the controls. This study demonstrated the high potential of endophytic fungi H. lixii and B. bassiana in inducing mainly specific defense compounds in the common bean P. vulgaris that can be used against pea leafminer and fall armyworm.

In agricultural ecosystems, insect pests, pathogens, weather patterns, and reduced soil fertility pose major challenges to crop productivity and are responsible for significant yield losses worldwide. Iris yellow spot virus (IYSV) vectored by Thrips tabaci Lindeman, is a major hindrance to onion production in eastern Africa. Control measures often rely on insecticides with deleterious effects. Endophytes are one key alternative as they can play important roles in mediating induced systemic resistance. Hence, we examined the potential effect of endophytic fungus Hypocrea lixii (F3ST1) on feeding and replication of IYSV on endophyte-colonized (E+) and endophyte-free (E-) onion plants. For more precise assessment, replication was also tested using leaf disk bioassays and individual thrips. The number of feeding punctures was significantly lower in E+ as compared to E- plants. Disease level was significantly lower in E+ as compared to E- plants for four weeks post-exposure to thrips. IYSV replication was reduced by 2.5-fold in endophytic treatment on both whole plant and leaf disk assays. Thrips tabaci showed 2 times higher feeding activities on endophyte-free onion leaf disks as compared to the endophyte-inoculated leaf disks. Our results suggest potential utility of the endophytes to reduce feeding damage and virus infection on onion plants. Further studies should be conducted to elucidate the secondary metabolites involved in such endophyte-thrips-virus mediated interaction and determine whether the interactions extend for this and other onion varieties and viruses under field conditions.

In agricultural ecosystems, insect pests, pathogens, weather patterns, and reduced soil fertility pose major challenges to crop productivity and are responsible for significant yield losses worldwide. Iris yellow spot virus (IYSV) vectored by Thrips tabaci Lindeman, is a major hindrance to onion production in eastern Africa. Control measures often rely on insecticides with deleterious effects. Endophytes are one key alternative as they can play important roles in mediating induced systemic resistance. Hence, we examined the potential effect of endophytic fungus Hypocrea lixii (F3ST1) on feeding and replication of IYSV on endophyte-colonized (E+) and endophyte-free (E-) onion plants. For more precise assessment, replication was also tested using leaf disk bioassays and individual thrips. The number of feeding punctures was significantly lower in E+ as compared to E- plants. Disease level was significantly lower in E+ as compared to E- plants for four weeks post-exposure to thrips. IYSV replication was reduced by 2.5-fold in endophytic treatment on both whole plant and leaf disk assays. Thrips tabaci showed 2 times higher feeding activities on endophyte-free onion leaf disks as compared to the endophyte-inoculated leaf disks. Our results suggest potential utility of the endophytes to reduce feeding damage and virus infection on onion plants. Further studies should be conducted to elucidate the secondary metabolites involved in such endophyte-thrips-virus mediated interaction and determine whether the interactions extend for this and other onion varieties and viruses under field conditions. [ABSTRACT FROM AUTHOR]

Field trials were carried out for two seasons in two sites (Sagana and Naromoru, Central province of Kenya) to evaluate the prospects of endophyte isolates of Beauveria bassiana (Balsamo) Vuillemin G1LU3 and Hypocrea lixii Patouillard F3ST1 for the control of Liriomyza leafminer in common bean Phaseolus vulgaris L. crops through seeds inoculation. Autodissemination device (AD) treated with conidia of Metarhizium anisopliae (Metschnikoff) Sorokin ICIPE 20 was also added as a treatment. Leafminer infestation was not significantly different during the first season but was higher in the controls than in endophtyte treatments at both sites during the second season. Three key Liriomyza species [( L. huidobrensis Blanchard, L. sativae Blanchard and L. trifolii (Burgess)] and six parasitoid species [( Opius dissitus Muesebeck, Phaedrotoma scabriventris Nixon, Diglyphus isaea Walker, Neochrysocharis formosa Westwood, Hemiptarsenus varicornis Girault and Halticoptera arduine (Walker)] were identified during the trials. Leafminer infestation, number of pupae, leafminer flies and parasitoids emergence and yield were the parameters evaluated. Both isolates successfully colonized different parts of P. vulgaris plants, although the colonization was higher with H. lixii F3ST1 than B. bassiana G1LU3 at both sites. The mean number of pupae from the infested leaves varied between 141-252 and 331-416 in endophyte and control treatments, respectively, during the first season and from 110-223 to 366-523, respectively, in endophyte and control treatments during the second season. There were no significant differences among the treatments in the number of parasitoids that emerged from pupae. Higher yield of P. vulgaris seeds was obtained in endophyte than in control treatments. The inclusion of AD treatment did not have significant effect on all the parameters evaluated, except yield. Results of the present study suggest that both fungal isolates hold potential for pest management and could be considered for the control of leafminer flies. However, there is the need to confirm these results on large-scale trials. [ABSTRACT FROM AUTHOR]

This work focused on the bioremoval of heavy metals by mangrove-derived Trichoderma biomass in the artificial sewage water. Of the 12 isolates tested, Hypocrea lixii TSK8 (JQ809340) was found to be a potent strain in removal of lead and iron. The bioremoval was enhanced through adsorption kinetics and process optimization using statistical model of the response surface methodology. The magnitude of Langmuir constant was 0.64 L mg and 0.42 L mg for lead and iron, respectively. Adsorption capacity was determined as 49.2 mg g and 51.3 mg g for lead and iron, respectively. The optimized conditions for maximum removal of lead and iron were standardized. The biosorption of metals was also confirmed by scanning electron microscopic and X-ray energy-dispersive spectrometer analyses. The results revealed that dried biomass of the H. lixii TSK8 was a potent biosorbent for efficient bioremoval of lead and iron. [ABSTRACT FROM AUTHOR]

Endophytic fungi colonize healthy plant tissues and can in some cases induce systemic resistance to the host against biotic and abiotic stresses. In our previous study, Hypocrea lixii isolate F3ST1 was able to colonize onion plants endophytically and conferred resistance to them against onion thrips, Thrips tabaci. To further elucidate the mechanism of resistance, we examined the behavioral response of adult and larval stages of T. tabaci to endophyte-inoculated (E+) and endophyte-free (E−) onion plants/sections. In choice experiments, female T. tabaci preferred E− over E+ plants. The number of feeding punctures and eggs was more on E− than on E+ plants. Oviposition was reduced sixfold on E+ plants within a 72-h experimental period. In the Y-tube olfactometer assay, thrips showed a 3.3-fold preference for E− plants. In individual larval choice experiments, significantly more first and second instars were found on the leaf sections of E− as compared to the E+ plants. In the settlement preference assay with groups of second instars, more larvae preferred leaf sections from E− over E+ plants with incremental time. Our findings suggest that endophyte-colonized onion plants may trigger antixenotic repellence of T. tabaci, impacting their biology. This repellence could be exploited in thrips control programs by using endophyte-inoculated plants in the field. [ABSTRACT FROM AUTHOR]

The aim of this work was to synthesize gold nanoparticles by Trichoderma viride and Hypocrea lixii. The biosynthesis of the nanoparticles was very rapid and took 10 min at 30 °C when cell-free extract of the T. viride was used, which was similar by H. lixii but at 100 °C. Biomolecules present in cell free extracts of both fungi were capable to synthesize and stabilize the formed particles. Synthesis procedure was very quick and environment friendly which did not require subsequent processing. The biosynthesized nanoparticles served as an efficient biocatalyst which reduced 4-nitrophenol to 4-aminophenol in the presence of NaBH4 and had antimicrobial activity against pathogenic bacteria. To the best of our knowledge, this is the first report of such rapid biosynthesis of gold nanoparticles within 10 min by Trichoderma having plant growth promoting and plant pathogen control abilities, which served both, as an efficient biocatalyst, and a potent antimicrobial agent. [ABSTRACT FROM AUTHOR]

This study developed mathematic models to convert ultraviolet-visible absorbance (UV/Vis) of bio-solublized coal to conversion ratios. By a mathematic regression method, the results showed that they had strong linear relationships. The highest correlation coefficient (0.99531) of the linear relationship between UV/Vis absorbance and coal bio-solubilization ratios was obtained at the wavelength of 513 nm. The high correlation coefficient further indicated that the use of UV/Vis with the proposed mathematic model would be an easier, quicker, and more accurate measurement, as compared with the conventional measurement of weighing coal loss after bio-solubilization. [ABSTRACT FROM PUBLISHER]

Aims The aim was to isolate, identify and characterize endophytes from pigeon pea ( Cajanus cajan [ L.] Millsp.), as novel producer of cajanol and its in vitro cytotoxicity assay. Methods and Results Isolation, identification and characterization of novel endophytes producing cajanol from the roots of pigeon pea were investigated. The endophytes were identified as Hypocrea lixii by morphological and molecular methods. Cajanol produced by endophytes were quantified by liquid chromatography-tandem mass spectrometry ( LC- MS/ MS). R-18 produced the highest levels of cajanol (322·4 ± 10·6 μg l−1 or 102·8 ± 6·9 μg g−1 dry weight of mycelium) after incubation for 7 days. The cytotoxicity towards human lung carcinoma cells ( A549) of fungal cajanol was investigated in vitro. Conclusions First, a novel endophyte Hypocrea lixii, producing anticancer agent cajanol, was isolated from the host pigeon pea ( Cajanus cajan [ L.] Millsp.). Fungal cajanol possessed stronger cytotoxicity activity towards A549 cells in time- and dose-dependent manners. Significance and Impact of the Study This endophyte is a potential handle for scientific and commercial exploitation, and it could provide a promising alterative approach for large-scale production of cajanol to satisfy new anticancer drug development. [ABSTRACT FROM AUTHOR]

Abstract: Aim: Mangrove is one of the oldest living tree species and its leaves are among the most extensively studied botanicals in use today. Scientific research throughout the world has found evidence to support the fact that its foliar extracts have great potential against human microbial pathogens. This study highlights the isolation of foliar fungi from Rhizophora mucronata, Avicenna officialis and Avicenna marina. Method: It was isolated in Sabouroud''s Dextrose Agar and mass cultivation was done in Sabouroud''s Dextrose broth. Results: The ethyl acetate extract showed maximum antibacterial activity which inturn checked for different concentration against bacterial pathogens and anticancer activity for Hep2 and MCF7 cell line in vitro. The DNA was isolated from the fungi and the ITS region of 5.8 s RNA was sequenced and assigned to new species as they are separated from the type strains phylogenetic neighbors by sequence similarities. Conclusion: This preliminary screening of fungal endophytes revealed their potential to yield potent bioactive compounds for drug discovery programmes. [Copyright &y& Elsevier]

Abstract: Fungi were isolated from natural soil samples and screened for extracellular dextranase synthesis. The strain F1002 was identified as Hypocrea lixii using a standard internal transcribed spacer ribosomal DNA analysis and was selected for extracellular dextranase synthesis. The enzyme was purified via ammonium sulfate precipitation and Sepharose 6B chromatography, which resulted in an 8.3-fold increase in the specific activity and a 10.73% recovery. This enzyme is a monomeric protein with a molecular mass of 62kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified enzyme, which was identified as an endodextranase, had an optimum pH of 5.0 and an optimum temperature of 25°C. The dextranase activity was enhanced by Mg2+, Al3+, and especially Zn2+ at a low concentration, which improved its activity to 124.22%. The enzyme has a very high hydrolytic affinity toward high-molecular weight dextrans. Setting the concentrations of the H. lixii F1002 dextranase (2.31U/mL) and dextrans (6%), as well as the reaction time (45min), allowed the dextranase to hydrolyze dextrans of controlled molecular weights (20–70kDa). Three types of oligodextrans with different molecular weights (namely, 69,376, 38,251, and 21,364Da) were obtained, with a total yield of 80.32%. [Copyright &y& Elsevier]

Aims: This study aimed to isolate and identify potential polycyclic aromatic hydrocarbon (PAH)-degrading and/or metal-tolerant fungi from PAH-contaminated and metal-contaminated soils. Methods and Results: Pyrene-degrading fungi were isolated from contaminated soil and tested for metal (Cu, Zn and Pb) compound solubilization and metal accumulation. Three strains of Fusarium solani and one of Hypocrea lixii were able to degrade more than 60% of initial supplied pyrene (100 mg l−1) after 2 weeks. The isolates were grown on toxic metal (Cu, Pb and Zn)-containing media: all isolates accumulated Cu in their mycelia to values ranging from c. 5·9 to 10·4 mmol per kg dry weight biomass. The isolates were also able to accumulate Zn ( c. 3·7–7·2 mmol per kg dry weight biomass) from zinc phosphate-amended media. None of the isolates accumulated Pb. Conclusions: These fungal isolates appear to show promise for use in bioremediation of pyrene or related xenobiotics and removal of copper and zinc from wastes contaminated singly or in combination with these substances. Significance and Impact of the Study: Microbial responses to mixed organic and inorganic pollution are seldom considered: this research highlights the abilities of certain fungal strains to interact with both xenobiotics and toxic metals and is relevant to other studies on natural attenuation and bioremediation of polluted sites. [ABSTRACT FROM AUTHOR]

A rapid subtraction hybridization approach was used to isolate genes differentially expressed during mycelial contact between Trichoderma harzianum ( Hypocrea lixii) and Rhizoctonia solani, and could serve as marker genes for selection of superior biocontrol strains. Putatively positive clones were evaluated by transcription analysis during mycelial contact with R. solani versus growth on glucose, and for their differential transcription between two strains with either strong or poor biocontrol capability before, at, and after contact with R. solani. Besides four clones, which had similarity to putative but as yet uncharacterized proteins, they comprised ribosomal proteins, proteins involved in transcriptional switch and regulation, amino acid and energy catabolism, multidrug resistance, and degradation of proteins and glucans. Transcription of three clones was evaluated in five T. harzianum strains under confrontation conditions with R. solani. Two clones—acetyl-xylane esterase AXE1 and endoglucanase Cel61b—showed significant upregulation during in vivo confrontation of a T. harzianum strain that successively demonstrated a very high antagonistic capability towards R. solani, while expression was progressively lower in a series of T. harzianum strains with intermediate to poor antagonistic activity. These clones are promising candidates for use as markers in the screening of improved T. harzianum biocontrol strains. [ABSTRACT FROM AUTHOR]

Endophytic fungal isolates Hypocrea lixii F3ST1 and Beauveria bassiana G1LU3 were evaluated for their potential to endophytically colonize and induce active compounds in Phaseolus vulgaris, as a defense mechanism against pea leafminer (Liriomyza huidobrensis) and fall armyworm (Spodoptera frugiperda). Endophytic colonization was achieved through seed inoculation with the volatile emissions from P. vulgaris plants being analyzed using GC-MS. The crude extracts of P. vulgaris obtained using methanol and dichloromethane were assayed against leafminer and fall armyworm larvae using leaf dipping and topical application, respectively. The two isolates successfully colonized the entire host plant (roots, stems, and leaves) with significant variation (p < 0.001) between fungal isolates and the controls. The results showed qualitative differences in the volatile profiles between the control plants, endophytically colonized and insect-damaged plants attributed to fungal inoculation and leafminer damage. The crude methanol extracts significantly reduced the percentage pupation of 2nd instar leafminer larvae (p < 0.001) and adult-flies emergence (p < 0.05). The survival of the 1st instar fall armyworm larvae was also significantly reduced (p < 0.001) compared to the controls. This study demonstrated the high potential of endophytic fungi H. lixii and B. bassiana in inducing mainly specific defense compounds in the common bean P. vulgaris that can be used against pea leafminer and fall armyworm. [ABSTRACT FROM AUTHOR]