Gravatt, Dennis , Taylor, Josephine , Edwards, Jennifer , Shadow, R. Alan , Gregory, Pam , Blacksher, K , George, A , Gibson, K , Kent, P , Kopycinski, J , Kouts, S , Letney, D , Maddox, D , Park, G , Rasure, C , Schmidt, N , Zachary, J .
Identification and Effects of Necrotrophic Fungal Pathogens on Indiangrass (Sorghastrum nutans).
Indiangrass (Sorghastrum nutans) is a perennial warm-season bunch grass susceptible to a number of fungal pathogens. The purpose of this investigation was to compare symptomatic and asymptomatic cultivars of indiangrass obtained from the East Texas Plant Materials Center,Nacogdoches, TX using a three-pronged approach: 1) evaluate the physiological effects of fungal infection through studies of photosynthesis, light saturation, and chlorophyll quantity, 2) examine the host/pathogen relationship through various forms of microscopy, and 3) determine fungal presence using a polymerase chain reaction (PCR) assay. Symptomatic and asymptomatic leaf samples were tested for photosynthetic response under decreasing light intensities and separately under established light saturation using a LI-COR 6400XT Portable Photosynthesis System. Symptomatic leaves consistently exhibited decreased physiological activity. Through microscopic analysis a cervuli of the fungal pathogen Colletotrichum were identified on 16.7% of symptomatic leaves. Epifluorescence light microscopy and transmission electron microscopy revealed limited growth of intercellular/intracellular hyphae and extensive disintegration of plant cells,consistent with the necrotrophic phase of Colletotrichum infection. Three distinct fungal phenotypes were cultured from infected tissues. Molecular DNA studies verified the presence of fungal DNA in both symptomatic and asymptomatic samples using a primer pair specific for ascomycetes and basidiomycetes. This study was part of a capstone graduate course for the Master Science Teacher Program at Stephen F. Austin State University.
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1 - Stephen F. Austin State University, DEPT OF BIOLOGY-PO BOX 13003, 1901 Raguet, Room 101, NACOGDOCHES, TX, 75965, USA
2 - Stephen F. Austin State University, Biology
3 - NRCS East Texas Plant Materials Center, Nacogdoches, TX
Presentation Type: Poster:Posters for Topics
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM