title: Effects of sugar beet chitinase IV on root-associated fungal community of transgenic silver birch in a field trial.
abstract: Heterogenous chitinases have been introduced in many plant species with the aim to increase the resistance of plants to fungal diseases. We studied the effects of the heterologous expression of sugar beet chitinase IV on the intensity of ectomycorrhizal (ECM) colonization and the structure of fungal communities in the field trial of 15 transgenic and 8 wild-type silver birch (Betula pendula Roth) genotypes. Fungal sequences were separated in denaturing gradient gel electrophoresis and identified by sequencing the ITS1 region to reveal the operational taxonomic units. ECM colonization was less intense in 7 out of 15 transgenic lines than in the corresponding non-transgenic control plants, but the slight decrease in overall ECM colonization in transgenic lines could not be related to sugar beet chitinase IV expression or total endochitinase activity. One transgenic line showing fairly weak sugar beet chitinase IV expression without significantly increased total endochitinase activity differed significantly from the non-transgenic controls in the structure of fungal community. Five sequences belonging to three different fungal genera (Hebeloma, Inocybe, Laccaria) were indicative of wild-type genotypes, and one sequence (Lactarius) indicated one transgenic line. In cluster analysis, the non-transgenic control grouped together with the transgenic lines indicating that genotype was a more important factor determining the structure of fungal communities than the transgenic status of the plants. With the tested birch lines, no clear evidence for the effect of the heterologous expression of sugar beet chitinase IV on ECM colonization or the structure of fungal community was found.
authors.affiliation: Department of Applied Biology, University of Helsinki, 00014 Helsinki, Finland. hanna.pasonen@helsinki.fi
authors.forename: Hanna-Leena
authors.initials: HL
authors.lastname: Pasonen
authors.forename: Jinrong
authors.initials: J
authors.lastname: Lu
authors.forename: Anna-Maija
authors.initials: AM
authors.lastname: Niskanen
authors.forename: Sanna-Kaisa
authors.initials: SK
authors.lastname: Seppänen
authors.forename: Anna
authors.initials: A
authors.lastname: Rytkönen
authors.forename: Janne
authors.initials: J
authors.lastname: Raunio
authors.forename: Ari
authors.initials: A
authors.lastname: Pappinen
authors.forename: Risto
authors.initials: R
authors.lastname: Kasanen
authors.forename: Sari
authors.initials: S
authors.lastname: Timonen
mesh_terms: D000704:Analysis of Variance; D027461:Beta vulgaris / Q000201:enzymology*; D029401:Betulaceae / Q000235:genetics* / Q000382:microbiology*; D015152:Blotting, Northern; D002688:Chitinases / Q000235:genetics / Q000378:metabolism*; D015169:Colony Count, Microbial; D005470:Fluorometry; D018506:Gene Expression Regulation, Plant; D038821:Mycorrhizae / Q000254:growth & development / Q000502:physiology*; D018517:Plant Roots / Q000235:genetics / Q000382:microbiology*; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D002688:Chitinases
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