Genetic Variability of Beauveria bassiana and a DNA Marker for Environmental Monitoring of a Highly Virulent Isolate Against Cosmopolites sordidus

The fungus Cylindrocarpon destructans (Zins) Scholten is the cause of root rot (disappearing root rot) in many ginseng production areas in Canada. A total of 80 isolates of C. destructans were recovered from diseased roots in a survey of ginseng gardens in British Columbia from 2002-2004. Among these isolates, 49% were classified as highly virulent (causing lesions on unwounded mature roots) and 51% were weakly virulent (causing lesions only on previously wounded roots). Pectinase and polyphenoloxidase enzymes were produced in vitro by C. destructans isolates when they were grown on pectin and phenol as a substrate, respectively. However, highly virulent isolates produced significantly (P < 0.001) higher enzyme levels compared with weakly virulent isolates. Histopathological studies of ginseng roots inoculated with a highly virulent isolate revealed direct hyphal penetration through the epidermis, followed by intracellular hyphal growth in the cortex. Subsequent cell disintegration and accumulation of phenolic compounds was observed. Radial growth of highly and weakly virulent isolates on potato dextrose agar was highest at 18 and 21°C, respectively and there was no growth at 35°C. Mycelial mass production was significantly (P ≤ 0.01) lower at pH 7.0 compared with pH 5.0. To study the effects of pH (5.0 and 7.0) and wounding on disease development, ginseng roots were grown hydroponically in Hoagland's solution. Lesions were significantly larger (P < 0.001) at pH 5.0 compared with pH 7.0 and wounding enhanced disease by a highly virulent isolate at both pHs. In artificially infested soil, 2-year-old ginseng roots were most susceptible to Cylindrocarpon root rot among all root ages tested (1 to 4 years) when evaluated using a combined scale of disease incidence and severity. Root rot severity was significantly (P < 0.002) enhanced by increasing the inoculum density from 3.45 × 102 CFU/g of soil to 1.86 × 103 CFU/g of soil. Disease severity was higher at 20°C compared with 15 and 25°C and at -0.02 MPa soil moisture compared with -0.005 and -0.001 MPa. A significant interaction between soil moisture and temperature was observed for root rot severity.

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Peer Review #2 of "Evaluation of a type 2 modified live porcine reproductive and respiratory syndrome vaccine against heterologous challenge of a lineage 3 highly virulent isolate in pigs (v0.1)"

10.7287/peerj.8840v0.1/reviews/2 ◽

2020 ◽

Keyword(s):

Peer Review ◽

Virulent Isolate ◽

Heterologous Challenge ◽

Highly Virulent

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Variability and Virulence Analysis of Aspergillus niger Isolates Causing Collar Rot of Groundnut

Legume Research - An International Journal ◽

10.18805/lr-4854 ◽

2022 ◽

Author(s):

Tejpal Bajaya ◽

R.P. Ghasolia ◽

Mamta Bajya ◽

Manisha Shivran

Keyword(s):

Aspergillus Niger ◽

Disease Incidence ◽

Morphological Variability ◽

Economic Losses ◽

Resistance Response ◽

Collar Rot ◽

Virulent Isolate ◽

Resistant Varieties ◽

Severe Constraint ◽

Highly Virulent

Background: Collar rot of groundnut (Arachis hypogaea L.) caused by Aspergillus niger is a significant constraint in groundnut cultivation and responsible for huge economic losses in India including Rajasthan. Methods: By surveying of eight major groundnut growing districts of Rajasthan, India, one representative Aspergillus niger isolate from each district was established (ANBK-01= Bikaner, ANCH-02= Churu, ANDA-03= Dausa, ANJP-04= Jaipur, ANJL-05= Jalore, ANJD-06= Jodhpur, ANNG-07= Nagaur and ANSK-08= Sikar) for studying variability in the pathogen as well as to know the response of groundnut varieties to the highly virulent isolate. The colony and spore characteristics were observed for cultural and morphological variability. For resistance response to the disease, ten varieties (M-13, RG-633-9, RG-382, Girnar-2, RG-604, RG-578, Gajraj 10, RG-510, RG-632-1 and RG-644) were evaluated in the field for two consecutive years against a highly virulent Aspergillus niger (ANJP-04) isolate. Result: Our investigations cleared that all the isolates were showed cultural and morphological variability such as shape, colour and size of colony and size of conidia, conidiophores and columella. Isolate (ANJP-04) collected from Khejroli village of Chomu tehsil in Jaipur district showed maximum mycelial growth, conidia diameter, length and diameter of conidiophores and length and diameter of columella, early sporulation and found most virulent as it produced higher disease incidence (54.43%). Ten released varieties of groundnut in the field conditions, revealed that none of the variety was found completely free from the disease whereas RG-644, M-13 and RG-510 were found resistant while RG-604, Girnar-2, Gajraj-10 and RG-632-1 were found moderately resistant and rest were found susceptible to highly susceptible to the disease. Conclusively, it can be finalized that famers may cultivate these resistant varieties in areas where collar rot is a severe constraint. The conclusion of this study can also be utilized to screen varieties/genotypes of groundnut against highly virulent isolate for sustainability of breeding material to the disease effectively.

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Potential for recombinant Babesia bovis antigens to protect against a highly virulent isolate

Parasite Immunology ◽

10.1111/j.1365-3024.2005.00795.x ◽

2005 ◽

Vol 27 (12) ◽

pp. 439-445 ◽

Cited By ~ 14

Author(s):

M. HOPE ◽

G. RIDING ◽

M. MENZIES ◽

I. COLDITZ ◽

A. REVERTER ◽

...

Keyword(s):

Babesia Bovis ◽

Virulent Isolate ◽

Highly Virulent

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Functional Expression of the Gene cu, Encoding the Phytotoxic Hydrophobin Cerato-ulmin, Enables Ophiostoma quercus, a Nonpathogen on Elm, to Cause Symptoms of Dutch Elm Disease

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2000.13.1.43 ◽

2000 ◽

Vol 13 (1) ◽

pp. 43-53 ◽

Cited By ~ 27

Author(s):

Giovanni Del Sorbo ◽

Felice Scala ◽

Giuseppe Parrella ◽

Matteo Lorito ◽

Cecilia Comparini ◽

...

Keyword(s):

Vascular Tissue ◽

Functional Expression ◽

Dutch Elm Disease ◽

Enzyme Linked Immunosorbent Assay ◽

Virulent Isolate ◽

Vascular Discoloration ◽

Encoding Gene ◽

Moderately Resistant ◽

Highly Virulent

We studied the involvement of the phytotoxic hydrophobin cerato-ulmin (CU) in pathogenesis and virulence of Dutch elm disease (DED) by expressing its encoding gene (cu) in Ophiostoma quercus, a nonpathogenic species on elm closely related to the DED pathogens O. ulmi and O. novo-ulmi. The production of the toxin was quantitatively determined in culture filtrates and in mycelial extracts of the transformants. Production of CU in vitro was associated with the ability to cause typical DED symptoms, consisting of foliar yellow and wilting and vascular tissue discoloration on a moderately resistant elm genotype. The presence of CU was monitored by enzyme-linked immunosorbent assay in symptomatic leaves of plants inoculated with O. quercus transformants expressing CU and found to be associated with wilt symptoms. In general, the virulence of the cu-expressing transformants, as measured in terms of vascular discoloration and percentage of defoliation, was lower than that of the mildly pathogenic isolate E2 of O. ulmi. However, one transformant (C39) displayed a virulence level intermediate between that of E2 and 182, a highly virulent isolate of O. novo-ulmi. Our results indicate that CU production influences virulence in nonaggressive strains of Ophiostoma fungi.

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Peer Review #1 of "Evaluation of a type 2 modified live porcine reproductive and respiratory syndrome vaccine against heterologous challenge of a lineage 3 highly virulent isolate in pigs (v0.2)"

10.7287/peerj.8840v0.2/reviews/1 ◽

2020 ◽

Author(s):

R Mickaël

Keyword(s):

Peer Review ◽

Virulent Isolate ◽

Heterologous Challenge ◽

Highly Virulent

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Pathogenicity of Beauveria bassiana isolates toward Leptinotarsa decemlineata [Coleoptera : Chrysomelidae], Myzus persicae [Homoptera : Aphididae] and their predator Coleomegilla maculata lengi [Coleoptera : Coccinellidae]

Phytoprotection ◽

10.7202/706196ar ◽

2005 ◽

Vol 81 (1) ◽

pp. 15-22 ◽

Cited By ~ 19

Author(s):

S.I. Todorova ◽

D. Coderre ◽

J.-C. Côté

Keyword(s):

Beauveria Bassiana ◽

Myzus Persicae ◽

Leptinotarsa Decemlineata ◽

Insect Pests ◽

Green Peach Aphid ◽

Coleomegilla Maculata ◽

Potato Beetle ◽

Potential Development ◽

Beauveria Bassiana Isolates ◽

Highly Virulent

Ten isolates of Beauveria bassiana from different sources and geographical sites were evaluated under laboratory conditions at a concentration of 107 conidia ml-1 for their pathogenicity against two insect pests, the Colorado potato beetle (Leptinotarsa decemlineata) and the green peach aphid (Myzus persicae), and their predator, the spotted ladybird beetle (Coleomegilla maculata lengi). Six isolates were highly virulent to all three insect species. Four others showed different degrees of specificity. The isolates 49, 233 and 210087 were the most interesting for their potential development as biological control agents because they were highly virulent for the two insect pests and caused low mortality in the coccinellid.

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