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Nguya K. Maniania - One of the best experts on this subject based on the ideXlab platform.

  • Endophytic Colonization of Onions Induces Resistance Against Viruliferous Thrips and Virus Replication
    Frontiers Media S.A., 2018
    Co-Authors: Alexander Mutua Muvea, Sevgan Subramanian, Hans-michael Poehling, Sunday Ekesi, Nguya K. Maniania, Rainer Meyhöfer
    Abstract:

    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

  • prospects of fungal endophytes in the control of liriomyza leafminer flies in common bean phaseolus vulgaris under field conditions
    Biocontrol, 2016
    Co-Authors: Zipporah Osiemo Lagat, Jane Wairimu Gathage, Nguya K. Maniania
    Abstract:

    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.

  • Behavioral responses of Thrips tabaci Lindeman to endophyte-inoculated onion plants
    Journal of Pest Science, 2015
    Co-Authors: Alexander Mutua Muvea, Rainer Meyhöfer, Hans-michael Poehling, Sunday Ekesi, Nguya K. Maniania, S. Subramanian
    Abstract:

    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.

  • effects of endophyte colonization of vicia faba fabaceae plants on the life history of leafminer parasitoids phaedrotoma scabriventris hymenoptera braconidae and diglyphus isaea hymenoptera eulophidae
    PLOS ONE, 2014
    Co-Authors: J Van Den Berg, Nguya K. Maniania
    Abstract:

    Effects of the fungal endophytes Beauveria bassiana (isolates ICIPE 279, G1LU3, S4SU1) and Hypocrea lixii (isolate F3ST1) on the life-history of Phaedrotoma scabriventris and Diglyphus isaea, parasitoids of the pea leafminer Liriomyza huidobrensis, were studied in the laboratory. Parasitoids were allowed to parasitize 2(nd) and 3(rd) instar L. huidobrensis larvae reared on endophytically-inoculated faba bean, Vicia faba. In the control, parasitoids were reared on non-inoculated host plants. Parasitism, pupation, adult emergence and survival were recorded. No significant difference was observed between the control and the endophyte-inoculated plants in terms of parasitism rates of P. scabriventris (p = 0.68) and D. isaea (p = 0.45) and adult' survival times (p = 0.06). The survival period of the F1 progeny of P. scabriventris was reduced (p<0.0001) in B. bassiana S4SU1 to 28 days as compared to more than 40 days for B. bassiana G1LU3, ICIPE 279 and H. lixii F3ST1. However, no significant difference (p = 0.54) was observed in the survival times of the F1 progeny of D. isaea. This study has demonstrated that together, endophytes and parasitoids have beneficial effects in L. huidobrensis population suppression.

  • Colonization of Onions by Endophytic Fungi and Their Impacts on the Biology of Thrips tabaci
    PloS one, 2014
    Co-Authors: Alexander Mutua Muvea, Rainer Meyhöfer, Sevgan Subramanian, Hans-michael Poehling, Sunday Ekesi, Nguya K. Maniania
    Abstract:

    Endophytic fungi, which live within host plant tissues without causing any visible symptom of infection, are important mutualists that mediate plant–herbivore interactions. Thrips tabaci (Lindeman) is one of the key pests of onion, Allium cepa L., an economically important agricultural crop cultivated worldwide. However, information on endophyte colonization of onions, and their impacts on the biology of thrips feeding on them, is lacking. We tested the colonization of onion plants by selected fungal endophyte isolates using two inoculation methods. The effects of inoculated endophytes on T. tabaci infesting onion were also examined. Seven fungal endophytes used in our study were able to colonize onion plants either by the seed or seedling inoculation methods. Seed inoculation resulted in 1.47 times higher mean percentage post-inoculation recovery of all the endophytes tested as compared to seedling inoculation. Fewer thrips were observed on plants inoculated with Clonostachys rosea ICIPE 707, Trichoderma asperellum M2RT4, Trichoderma atroviride ICIPE 710, Trichoderma harzianum 709, Hypocrea lixii F3ST1 and Fusarium sp. ICIPE 712 isolates as compared to those inoculated with Fusarium sp. ICIPE 717 and the control treatments. Onion plants colonized by C. rosea ICIPE 707, T. asperellum M2RT4, T. atroviride ICIPE 710 and H. lixii F3ST1 had significantly lower feeding punctures as compared to the other treatments. Among the isolates tested, the lowest numbers of eggs were laid by T. tabaci on H. lixii F3ST1 and C. rosea ICIPE 707 inoculated plants. These results extend the knowledge on colonization of onions by fungal endophytes and their effects on Thrips tabaci.

Sunday Ekesi - One of the best experts on this subject based on the ideXlab platform.

  • Endophytic Colonization of Onions Induces Resistance Against Viruliferous Thrips and Virus Replication
    Frontiers Media S.A., 2018
    Co-Authors: Alexander Mutua Muvea, Sevgan Subramanian, Hans-michael Poehling, Sunday Ekesi, Nguya K. Maniania, Rainer Meyhöfer
    Abstract:

    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

  • Behavioral responses of Thrips tabaci Lindeman to endophyte-inoculated onion plants
    Journal of Pest Science, 2015
    Co-Authors: Alexander Mutua Muvea, Rainer Meyhöfer, Hans-michael Poehling, Sunday Ekesi, Nguya K. Maniania, S. Subramanian
    Abstract:

    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.

  • Colonization of Onions by Endophytic Fungi and Their Impacts on the Biology of Thrips tabaci
    PloS one, 2014
    Co-Authors: Alexander Mutua Muvea, Rainer Meyhöfer, Sevgan Subramanian, Hans-michael Poehling, Sunday Ekesi, Nguya K. Maniania
    Abstract:

    Endophytic fungi, which live within host plant tissues without causing any visible symptom of infection, are important mutualists that mediate plant–herbivore interactions. Thrips tabaci (Lindeman) is one of the key pests of onion, Allium cepa L., an economically important agricultural crop cultivated worldwide. However, information on endophyte colonization of onions, and their impacts on the biology of thrips feeding on them, is lacking. We tested the colonization of onion plants by selected fungal endophyte isolates using two inoculation methods. The effects of inoculated endophytes on T. tabaci infesting onion were also examined. Seven fungal endophytes used in our study were able to colonize onion plants either by the seed or seedling inoculation methods. Seed inoculation resulted in 1.47 times higher mean percentage post-inoculation recovery of all the endophytes tested as compared to seedling inoculation. Fewer thrips were observed on plants inoculated with Clonostachys rosea ICIPE 707, Trichoderma asperellum M2RT4, Trichoderma atroviride ICIPE 710, Trichoderma harzianum 709, Hypocrea lixii F3ST1 and Fusarium sp. ICIPE 712 isolates as compared to those inoculated with Fusarium sp. ICIPE 717 and the control treatments. Onion plants colonized by C. rosea ICIPE 707, T. asperellum M2RT4, T. atroviride ICIPE 710 and H. lixii F3ST1 had significantly lower feeding punctures as compared to the other treatments. Among the isolates tested, the lowest numbers of eggs were laid by T. tabaci on H. lixii F3ST1 and C. rosea ICIPE 707 inoculated plants. These results extend the knowledge on colonization of onions by fungal endophytes and their effects on Thrips tabaci.

  • Progeny survival curves of Diglyphus isaea emerging from Vicia faba plants endophytically-colonized by different fungal isolates of Beauveria bassiana (S4SU1, G1LU3 and ICIPE279) and Hypocrea lixii (F3ST1) and infested with 2nd and 3rd instar larvae of Liriomyza huidobrensis.
    2014
    Co-Authors: Komivi S. Akutse, Sunday Ekesi, J Van Den Berg, Komi K. M. Fiaboe, Nguya K. Maniania
    Abstract:

    Progeny survival curves of Diglyphus isaea emerging from Vicia faba plants endophytically-colonized by different fungal isolates of Beauveria bassiana (S4SU1, G1LU3 and ICIPE279) and Hypocrea lixii (F3ST1) and infested with 2nd and 3rd instar larvae of Liriomyza huidobrensis.

  • Progeny survival curves of Phaedrotoma scabriventris emerging from Vicia faba plants endophytically-colonized by different fungal isolates of Beauveria bassiana (S4SU1, G1LU3 and ICIPE279) and Hypocrea lixii (F3ST1) and infested with 2nd and 3rd instar larvae of Liriomyza huidobrensis.
    2014
    Co-Authors: Komivi S. Akutse, Sunday Ekesi, J Van Den Berg, Komi K. M. Fiaboe, Nguya K. Maniania
    Abstract:

    Progeny survival curves of Phaedrotoma scabriventris emerging from Vicia faba plants endophytically-colonized by different fungal isolates of Beauveria bassiana (S4SU1, G1LU3 and ICIPE279) and Hypocrea lixii (F3ST1) and infested with 2nd and 3rd instar larvae of Liriomyza huidobrensis.

J Van Den Berg - One of the best experts on this subject based on the ideXlab platform.

John Bissett - One of the best experts on this subject based on the ideXlab platform.

  • The Trichoderma harzianum demon: complex speciation history resulting in coexistence of hypothetical biological species, recent agamospecies and numerous relict lineages
    BMC Evolutionary Biology, 2010
    Co-Authors: Irina S Druzhinina, Christian P Kubicek, Monika Komoń-zelazowska, Temesgen Belayneh Mulaw, John Bissett
    Abstract:

    The mitosporic fungus Trichoderma harzianum (Hypocrea, Ascomycota, Hypocreales, Hypocreaceae) is an ubiquitous species in the environment with some strains commercially exploited for the biological control of plant pathogenic fungi. Although T. harzianum is asexual (or anamorphic), its sexual stage (or teleomorph) has been described as Hypocrea lixii. Since recombination would be an important issue for the efficacy of an agent of the biological control in the field, we investigated the phylogenetic structure of the species. Using DNA sequence data from three unlinked loci for each of 93 strains collected worldwide, we detected a complex speciation process revealing overlapping reproductively isolated biological species, recent agamospecies and numerous relict lineages with unresolved phylogenetic positions. Genealogical concordance and recombination analyses confirm the existence of two genetically isolated agamospecies including T. harzianum sensu stricto and two hypothetical holomorphic species related to but different from H. lixii. The exact phylogenetic position of the majority of strains was not resolved and therefore attributed to a diverse network of recombining strains conventionally called 'pseudoharzianum matrix'. Since H. lixii and T. harzianum are evidently genetically isolated, the anamorph - teleomorph combination comprising H. lixii/T. harzianum in one holomorph must be rejected in favor of two separate species. Our data illustrate a complex speciation within H. lixii - T. harzianum species group, which is based on coexistence and interaction of organisms with different evolutionary histories and on the absence of strict genetic borders between them.

Priscila Chaverri - One of the best experts on this subject based on the ideXlab platform.

  • multilocus phylogenetic structure within the trichoderma harzianum Hypocrea lixii complex
    Molecular Phylogenetics and Evolution, 2003
    Co-Authors: Priscila Chaverri, Gary J. Samuels, Lisa A Castlebury, David M. Geiser
    Abstract:

    Trichoderma harzianum is a ubiquitous species in the environment and is effective in the biological control of plant-pathogenic fungi. T. harzianum has not been linked unequivocally to its sexual state nor has its phylogeny been studied in detail. It has been suggested that T. harzianum is a species complex based on the phenotypic and genotypic variability encountered. On the basis of morphological and cultural characters and DNA sequence data analysis of four genes (ITS rDNA, translation elongation factor 1-alpha, calmodulin, and alpha-actin), Hypocrea lixii was found to be the sexual state of T. harzianum. Both the asexual and sexual states of this species have wide geographic distributions. Phylogenetic analysis of four genes showed that T. harzianum/H. lixii is a cohesive group that is supported by bootstrap values higher than 95%. Principles of genealogical concordance indicated that T. harzianum/H. lixii is a complex of independent monophyletic lineages, but no diagnostic morphological distinctions were identified that justify formal taxonomic recognition for the different lineages.

  • Multilocus phylogenetic structure within the Trichoderma harzianum/Hypocrea lixii complex
    2003
    Co-Authors: Priscila Chaverri, Lisa A Castlebury, Gary B J. Samuels, David M. Geisera
    Abstract:

    Trichoderma harzianum is a ubiquitous species in the environment and is effective in the biological control of plant-pathogenic fungi. T. harzianum has not been linked unequivocally to its sexual state nor has its phylogeny been studied in detail. It has been suggested that T. harzianum is a species complex based on the phenotypic and genotypic variability encountered. On the basis of morphological and cultural characters and DNA sequence data analysis of four genes (ITS rDNA, translation elongation factor 1-a, calmodulin, and a-actin), Hypocrea lixii was found to be the sexual state of T. harzianum. Both the asexual and sexual states of this species have wide geographic distributions. Phylogenetic analysis of four genes showed that T. harzianum/H. lixii is a cohesive group that is supported by bootstrap values higher than 95%. Principles of genealogical concordance indicated that T. harzianum/H. lixii is a complex of independent monophyletic lineages, but no diagnostic morphological distinctions were identified that justify formal taxonomic recognition for the different lineages

  • Hypocrea lixii, the teleomorph of Trichoderma harzianum
    Mycological Progress, 2002
    Co-Authors: Priscila Chaverri, Gary J. Samuels
    Abstract:

    Cultures derived from ascospores of Hypocrea lixii (= H. nigricans, H. lentiformis) produced the morphological species Trichoderma harzianum in pure culture. Trichoderma harzianum, the most commonly found species of the genus, is also one of the most species frequently used in biocontrol of plant pathogens. It has not been connected previously to a teleomorph. The connection was confirmed by DNA sequence analysis. Similar to the anamorph, the teleomorph collections have a wide geographic distribution. Described in the 19th century, Hypocrea lixii is epitypified by a collection from Thailand.