MSA - Ecology/Pathology
Stefani, Franck O.P. , Tanguay, Philippe , Piché, Yves .
Assessing the impact of transgenic endochitinase white spruce on mycorrhizal fungi.
The impact of transgenic white spruce (Picea glauca (Moench) Voss) containing the endochitinase gene (ech42) on species diversity mycorrhizal root tips, total soil fungal biomass, and biomass of the ectendomycorrhizal fungus Wilcoxina spp. was studied in greenhouse experiments. Eleven white spruce seedlings from four transformed lines and a wild-type control were grown for five years in a greenhouse. The level of endochitinase-specific activity measured in the roots of transgenic white spruce was 20 times higher than in the roots of non-transformed white spruce. ITS rDNA analysis of a total of 155 root tips isolated from control and ech42 white spruces showed that a fungus identified as Wilcoxina spp. was the predominant species (colonizing 76.7% of the root tips analyzed), followed by Phialocephala fortinii (12.2%), an uncultured atheliaceae (4.2%) and Thelephora terrestris (3.3%). Ergosterol, a fungal-specific sterol, was extracted from the soil and quantified using HPLC as a measure of total fungal biomass. Soil samples from control white spruce displayed a slightly higher amount of ergosterol than soil samples from transformed white spruce, but the difference was not statistically significant. Quantitative real-time PCR (qPCR) was performed on root tips colonized by Wilcoxina spp. to detect the impact of endochitinase expressing roots on the development of this ectendomycorrhizal symbiosis. Preliminary results showed no difference between control and ech42 white spruces. Overall, no impact in terms of fungal species diversity and fungal biomass was observed between wild-type and transgenic white spruce lines overexpressing ech42 endochitinase.
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1 - Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, Québec, G1V 4C7, Canada
2 - Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, Québec, G1V 4C7, Canada
3 - Université Laval, Département des sciences du bois et de la forêt, Faculté de Foresterie et de Géomatique, 1030 avenue de la Médecine, Pavillon C.-E.-Marchand, Québec, Québec, G1V 0A6, Canada
Presentation Type: Oral Paper:Papers for Topics
Location: Cottonwood B/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 11:00 AM