title: Photochemical processes, carbon assimilation and RNA accumulation of sucrose transporter genes in tomato arbuscular mycorrhiza.
abstract: Arbuscular mycorrhizal fungi enhance CO₂ assimilation of their hosts which ensure the demand for carbohydrates of these obligate biotrophic microorganisms. Photosynthetic parameters were measured in tomato colonised or not by the arbuscular mycorrhizal fungus Glomus mosseae. In addition, carbohydrate contents and mRNA accumulation of three sucrose transporter genes were analysed. Mycorrhizal plants showed increased opening of stomata and assimilated significant more CO₂. A higher proportion of the absorbed light was used for photochemical processes, while non-photochemical quenching and the content of photoprotective pigments were lower. Analysis of sugar contents showed no significant differences in leaves but enhanced levels of sucrose and fructose in roots, while glucose amounts stayed constant. The three sucrose transporter encoding genes of tomato SlSUT1, SlSUT2 and SlSUT4 were up-regulated providing transport capacities to transfer sucrose into the roots. It is proposed that a significant proportion of sugars is used by the mycorrhizal fungus, because only amounts of fructose were increased, while levels of glucose, which is mainly transferred towards the fungus, were nearly constant.
authors.affiliation: Leibniz-Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1, D-14979 Grossbeeren, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Boldt
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Pörs
authors.forename: Bastian
authors.initials: B
authors.lastname: Haupt
authors.forename: Michael
authors.initials: M
authors.lastname: Bitterlich
authors.forename: Christina
authors.initials: C
authors.lastname: Kühn
authors.forename: Bernhard
authors.initials: B
authors.lastname: Grimm
authors.forename: Philipp
authors.initials: P
authors.lastname: Franken
mesh_terms: D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis; D005453:Fluorescence; D005632:Fructose / Q000032:analysis / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008027:Light; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D038821:Mycorrhizae / Q000254:growth & development* / Q000378:metabolism; D010710:Phosphates / Q000032:analysis; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology; D054046:Plant Stomata / Q000378:metabolism; D018526:Plant Transpiration; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D013395:Sucrose / Q000032:analysis / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D026901:Membrane Transport Proteins; D010710:Phosphates; D010940:Plant Proteins; D012333:RNA, Messenger; C078729:sucrose transport protein, plant; D002734:Chlorophyll; D002245:Carbon Dioxide; D005632:Fructose; D013395:Sucrose; D002244:Carbon