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Author Meyer, Susan E. ♦ Stewart, Thomas E. ♦ Clement, Suzette
Source World Health Organization (WHO)-Global Index Medicus
Content type Text
Publisher Wiley
File Format HTM / HTML
Language English
Difficulty Level Medium
Subject Domain (in DDC) Social sciences ♦ Social problems & services; associations ♦ Social welfare problems & services ♦ Natural sciences & mathematics ♦ Life sciences; biology ♦ Physiology & related subjects ♦ Natural history of organisms ♦ Microorganisms, fungi & algae ♦ Technology ♦ Medicine & health ♦ Human anatomy, cytology, histology ♦ Human physiology
Subject Domain (in MeSH) Plant Structures ♦ Fungal Structures ♦ Anatomy ♦ Eukaryota ♦ Organisms ♦ Microbiological Phenomena ♦ Biological Sciences ♦ Health Care Facilities, Manpower, and Services ♦ Health Care
Subject Keyword Discipline Botany ♦ Ascomycota ♦ Growth & Development ♦ Pathogenicity ♦ Biological Specimen Banks ♦ Bromus ♦ Microbiology ♦ Seeds ♦ Isolation & Purification ♦ Mycelium ♦ Virulence ♦ Comparative Study ♦ Journal Article ♦ Research Support, Non-u.s. Gov't
Abstract *We studied the relationship between virulence (ability to kill nondormant Bromus tectorum seeds) and mycelial growth index in the necrotrophic seed pathogen Pyrenophora semeniperda. Seed pathosystems involving necrotrophs differ from those commonly treated in traditional evolution-of-virulence models in that host death increases pathogen fitness by preventing germination, thereby increasing available resources. Because fast-germinating, nondormant B. tectorum seeds commonly escape mortality, we expected virulence to be positively correlated with mycelial growth index. *We performed seed inoculations using conidia from 78 pathogen isolates and scored subsequent mortality. For a subset of 40 of these isolates, representing a range of virulence phenotypes, we measured mycelial growth index. *Virulence varied over a wide range (3-43% seed mortality) and was significantly negatively correlated with mycelial growth index (R(2) = 0.632). More virulent isolates grew more slowly than less virulent isolates. *We concluded that there is an apparent tradeoff between virulence and growth in this pathogen, probably because the production of toxins necessary for necrotrophic pathogenesis competes with metabolic processes associated with growth. Variation in both virulence and growth rate in this pathosystem may be maintained in part by seasonal variation in the relative abundance of rapidly germinating vs dormant host seeds available to the pathogen.
Description Country affiliation: United States
Author Affiliation: Meyer SE ( US Forest Service, Rocky Mountain Research Station, Shrub Sciences Laboratory, 735 North 500 East, Provo, UT 84606, USA.
ISSN 0028646X
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Reading ♦ Research ♦ Self Learning
Interactivity Type Expositive
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2010-07-01
Publisher Place Great Britain (UK)
e-ISSN 14698137
Journal New Phytologist
Volume Number 187
Issue Number 1

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Source: WHO-Global Index Medicus