The present study was carried out to assess the effects on the ovary of fed female Argas persicus following spraying of the ticks with spores of the fungus Beauveria bassiana suspended in triton X100 ...at a concentration of 107 conidia/mL. Scanning and transmission electron microscopy observations provided evidence that B. bassiana invaded the ovary, causing extensive morphological damage and deterioration of the developing oocytes. Destruction of the shape and internal organelles of young and previtellogenic oocytes and complete inhibition of vitellogenesis was evident. This histopathological study is the first demonstration of ultrastructural damage in the ovaries of A. persicus after infection with B. bassiana. The data presented confirm that B. bassiana affects the ovary either directly by entering the oocytes and/or indirectly by producing toxins in the haemolymph that interfere with the development of oocytes, thus potentially contributing to the control of this tick in a way that is safe for its host and the environment.
Aims
Peroxins Pex5 and Pex7 belong to the peroxisomal import machinery and recognize proteins containing peroxisomal targeting signal (PTS) type 1 and type 2, respectively. This study seeks to ...characterize these two peroxins in the entomopathogenic fungus Beauveria bassiana.
Methods and Results
The orthologs of Pex5 and Pex7 in B. bassiana (BbPex5 and BbPex7) were functionally analyzed via protein localization and gene disruption. BbPex5 and BbPex7 were associated with peroxisome and specifically required for PTS1 and PTS2 pathways, respectively, which were demonstrated to be involved in development, tolerance to oxidative stress and virulence. ΔBbPex5 mutant displayed additionally defectives that were undetected in ΔBbPex7 in vegetative growth and resistance to osmotic and cell wall‐perturbing stresses. Notably, Woronin body major protein Hex1 with PTS1 linked this organelle to the development and virulence of B. bassiana, which indicates that Woronin body is associated with the roles of PTS1 pathway.
Conclusion
Both PTS1 and PTS2 pathways are involved in broad physiological process, and the PTS1 pathway acts as a main peroxisomal import pathway.
Significance and Impact of the Study
This study shows the functional divergence of different peroxins and improves our understanding of organellar physiology involved in biocontrol potential of the entomopathogenic fungi.
Based on morphological and molecular phylogenetic markers and the fertility of sexual crosses, two novel species of Fusarium associated with Dactylopius opuntiae (Hemiptera: Dactylopiidae) and ...Aleurocanthus woglumi (Hemiptera: Aleyrodidae) from northeastern Brazil are described as Fusarium caatingaense and F. pernambucanum. Partial sequences of five loci were generated for 29 entomopathogenic Fusarium isolates. Multilocus phylogenetic analyses demonstrated that F. caatingaense and F. pernambucanum belong to the Incarnatum clade of the Fusarium incarnatum-equiseti species complex (FIESC). These species displayed common morphological characters such as the production of various types of aerial conidia formed on monophialides and polyphialides and differ from each other mainly in the dimensions and morphology of their sporodochial conidia. Mating type polymerase chain reaction (PCR) revealed 17 MAT1-1 isolates and 12 MAT1-2 isolates, all of them heterothallic. Fertile perithecia were produced in 4.2% of infraspecific crosses of F. caatingaense and in 13.3% of infraspecific crosses of F. pernambucanum after 2-3 wk. Crosses between F. caatingaense and F. pernambucanum did not result in fertile perithecia. We demonstrate the existence of a sexual stage in species of the Incarnatum clade and describe the morphological characters of these sexual morphs for the first time. These results suggest that previously unknown sexual cycles contribute to the high genetic diversity within FIESC.
Ophiocordyceps species infecting ants – the so-called zombie-ant fungi – comprise one of the most intriguing and fascinating relationships between microbes and animals. They are widespread within ...tropical forests worldwide, with relatively few reports from temperate ecosystems. These pathogens possess the ability to manipulate host behaviour in order to increase their own fitness. Depending on the fungal species involved the infected ants are manipulated either to leave the nest to ascend understorey shrubs, to die biting onto vegetation, or descend from the canopy to die at the base of trees. Experimental evidence has demonstrated that the behavioural change aids spore dispersal and thus increases the chances of infection, because of the existing behavioural immunity expressed inside ant colonies that limits fungal development and transmission. Despite their undoubted importance for ecosystem functioning, these fungal pathogens are still poorly documented, especially regarding their diversity, ecology and evolutionary relationships. Here, we describe 15 new species of Ophiocordyceps with hirsutella-like asexual morphs that exclusively infect ants. These form a monophyletic group that we identified in this study as myrmecophilous hirsutelloid species. We also propose new combinations for species previously described as varieties and provide for the first time important morphological and ecological information. The species proposed herein were collected in Brazil, Colombia, USA, Australia and Japan. All species could readily be separated using classic taxonomic criteria, in particular ascospore and asexual morphology.
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•Successful endophytic establishment of the entomopathogen B. bassiana in grapevine plants.•In potted plants endophytic survival of B. bassiana was evident for at least 21days after ...inoculation.•Endophytic B. bassiana reduces infestation rate and growth of vine mealybugs.•In the vineyard B. bassiana was detected as an endophyte up to five weeks after last application.•B. bassiana reduces infestation with grape leafhopper in the vineyard.
Fungi are important natural pathogens of arthropod pests and are successfully used as biocontrol agents in various crops. In addition to colonizing arthropods, evidence has accumulated that some entomopathogenic fungi like Beauveria bassiana can endophytically colonize a wide array of plant species. However, only limited information is currently available on the endophytic colonization of grapevines with B. bassiana and whether the fungus still maintains its pathogenic habit against insect pests.
Greenhouse and field experiments were conducted to optimize endophytic establishment of the entomopathogenic fungus B. bassiana in younger, potted plants and mature grapevine plants in the vineyard. We used two different commercialized B. bassiana strains, applied either as conidial suspensions (ATCC 74040 and GHA) or as a formulated product (Naturalis®, strain ATCC 74040) on grapevine leaves. The potential of endophytic B. bassiana to provide protection against putative target pest insects like the vine mealybug Planococcus ficus was assessed in a bioassay using surface sterilized leaves. Endophytic survival of B. bassiana inside leaf tissues of seven-week-old potted plants was evident for at least 21days after inoculation, irrespective of the inoculum used. Endophytic B. bassiana reduces infestation rate and growth of P. ficus. In the vineyard B. bassiana was detected as an endophyte in mature grapevine plants up to five weeks after last application with significant reduction of infestation with grape leafhopper, Empoasca vitis.
During surveys in central Florida of the zombie-ant fungus Ophiocordyceps camponoti-floridani, which manipulates the behavior of the carpenter ant Camponotus floridanus, two distinct fungal ...morphotypes were discovered associated with and purportedly parasitic on O.
camponoti-floridani. Based on a combination of unique morphology, ecology and phylogenetic placement, we discovered that these morphotypes comprise two novel lineages of fungi. Here, we propose two new genera, Niveomyces and Torrubiellomyces, each including a single species
within the families Cordycipitaceae and Ophiocordycipitaceae, respectively. We generated de novo draft genomes for both new species and performed morphological and multi-loci phylogenetic analyses. The macro-morphology and incidence of both new species, Niveomyces coronatus
and Torrubiellomyces zombiae, suggest that these fungi are mycoparasites since their growth is observed exclusively on O. camponoti-floridani mycelium, stalks and ascomata, causing evident degradation of their fungal hosts. This work provides a starting point for more studies
into fungal interactions between mycopathogens and entomopathogens, which have the potential to contribute towards efforts to battle the global rise of plant and animal mycoses.
Nelly N, Syahrawati MY, Hamid H, Habazar T, Gusnia DN. 2019. Diversity and characterization of entomopathogenic fungi from rhizosphere of maize plants as potential biological control agents. ...Biodiversitas 20: 1435-1441. The diversity and characters of entomopathogenic fungi in soil are influenced by cultivation techniques. This study aims at determining the characters and pathogenicity of entomopathogenic fungi in maize plant. Materials were extracted from maize plant rhizosphere at different planting system (monoculture, polyculture, and monoculture of corn on formerly oil palm plantation or replanting) in Nagari Koto Baru, Luhak Nan Duo Subdistrict, West Pasaman District, and West Sumatra Province. Insect bait and series dilution were used to carry out the isolation, while Tenebrio molitor larvae were used for the pathogenicity test. Parameters observed include macroscopic and microscopic characteristics, and pathogenicity of entomopathogenic fungi. The result shows that there are three types of entomopathogenic fungi with various features. After identification, it was known that Aspergillus and Metarizium were obtained from mono, polyculture and by replanting crops, while Beauveria was found from the rhizosphere of corn grown in polyculture with pathogenicity identified as one of the high causes of death to larvae T. molitor with LT50 ranging from 48.03-48.48 hours.
Key words: Characterisation, diversity, entomopathogenic fungi, rhizosphere
Over the last two decades the molecular phylogeny and classification of Metarhizium has been widely studied. Despite these efforts to understand this enigmatic genus, the basal lineages in ...Metarhizium are still poorly resolved. In this study, a phylogenetic framework is reconstructed for the Clavicipitaceae focusing on Metarhizium through increased taxon-sampling using five genomic loci (SSU, LSU, tef, rpb1, rpb2) and the barcode marker ITS rDNA. Multi-gene phylogenetic analyses and morphological characterisation of green-spored entomopathogenic Metarhizium isolates from Thailand and soil isolates of M. carneum and M. marquandii reveal their ecological, genetic and species diversity. Nineteen new species are recognised in the Metarhizium clade with narrow host ranges: two new species are found in the M. anisopliae complex – M. clavatum on Coleoptera larvae and M. sulphureum on Lepidoptera larvae; four new species are found in the M. flavoviride complex – M. biotecense and M. fusoideum on brown plant hoppers (Hemiptera), M. culicidarum on mosquitoes, M. nornnoi on Lepidoptera larvae; three new species M. megapomponiae, M. cicadae, M. niveum occur on cicadas; five new species M. candelabrum, M. cercopidarum, M. ellipsoideum, M. huainamdangense M. ovoidosporum occur on planthoppers, leafhoppers and froghoppers (Hemiptera); one new species M. eburneum on Lepidoptera pupae; and four new species M. phuwiangense, M. purpureum, M. purpureonigrum, M. flavum on Coleoptera. Of these 19 new species, seven produce a sexual morph (M. clavatum, M. eburneum, M. flavum, M. phuwiangense, M. purpureonigrum, M. purpureum, and M. sulphureum) and asexual morphs are found in the remaining new species and also in M. sulphureum, M. purpureonigrum and M. purpureum. Metarhizium blattodeae, M. koreanum and M. viridulum are new records for Thailand. An alternative neotype for Metarhizium anisopliae is proposed based on multi-gene and 5′tef analyses showing that CBS 130.71 from Ukraine is more suitable, being from a much closer geographical location to Metchnikoff’s Metarhizium anisopliae. This isolate is distinct from the neotype of Metarhizium anisopliae var. anisopliae proposed by M. Tulloch from Ethiopia (ARSEF 7487). Six new genera are established for monophyletic clades subtending the core Metarhizium clade, including Keithomyces, Marquandomyces, Papiliomyces, Purpureomyces, Sungia, and Yosiokobayasia. Metarhizium carneum, M. aciculare, and M. neogunnii are combined in Keithomyces and one new combination for M. marquandii in Marquandomyces is proposed. Purpureomyces is introduced for species producing purple stromata including a new combination for M. khaoyaiense and two new species P. maesotensis and P. pyriformis. Papiliomyces contains two new combinations for M. liangshanense and Metacordyceps shibinensis. The genus Sungia is proposed for the Korean species M. yongmunense on Lepidoptera pupa and Yosiokobayasia for the Japanese species M. kusanagiense also on Lepidoptera pupa. A synoptic and dichotomous key to the accepted taxa is provided together with tables listing distinguishing morphological characters between species, host preferences, and geography.
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