title: Overexpression of Laccaria bicolor aquaporin JQ585595 alters root water transport properties in ectomycorrhizal white spruce (Picea glauca) seedlings.
abstract: The contribution of hyphae to water transport in ectomycorrhizal (ECM) white spruce (Picea glauca) seedlings was examined by altering expression of a major water-transporting aquaporin in Laccaria bicolor. Picea glauca was inoculated with wild-type (WT), mock transgenic or L. bicolor aquaporin JQ585595-overexpressing (OE) strains and exposed to root temperatures ranging from 5 to 20°C to examine the root water transport properties, physiological responses and plasma membrane intrinsic protein (PIP) expression in colonized plants. Mycorrhization increased shoot water potential, transpiration, net photosynthetic rates, root hydraulic conductivity and root cortical cell hydraulic conductivity in seedlings. At 20°C, OE plants had higher root hydraulic conductivity compared with WT plants and the increases were accompanied by higher expression of P. glauca PIP GQ03401_M18.1 in roots. In contrast to WT L. bicolor, the effects of OE fungi on root and root cortical cell hydraulic conductivities were abolished at 10 and 5°C in the absence of major changes in the examined transcript levels of P. glauca root PIPs. The results provide evidence for the importance of fungal aquaporins in root water transport of mycorrhizal plants. They also demonstrate links between hyphal water transport, root aquaporin expression and root water transport in ECM plants.
authors.affiliation: Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada.
authors.forename: Hao
authors.initials: H
authors.lastname: Xu
authors.forename: Minna
authors.initials: M
authors.lastname: Kemppainen
authors.forename: Walid
authors.initials: W
authors.lastname: El Kayal
authors.forename: Seong Hee
authors.initials: SH
authors.lastname: Lee
authors.forename: Alejandro G
authors.initials: AG
authors.lastname: Pardo
authors.forename: Janice E K
authors.initials: JE
authors.lastname: Cooke
authors.forename: Janusz J
authors.initials: JJ
authors.lastname: Zwiazek
mesh_terms: D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D018506:Gene Expression Regulation, Plant; D055399:Laccaria / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D038821:Mycorrhizae / Q000378:metabolism; D030781:Organisms, Genetically Modified; D028222:Picea / Q000378:metabolism* / Q000382:microbiology; D018517:Plant Roots / Q000378:metabolism* / Q000382:microbiology*; D036226:Seedlings / Q000378:metabolism* / Q000382:microbiology; D014867:Water / Q000378:metabolism
chemical_list: D020346:Aquaporins; D005656:Fungal Proteins; D014867:Water
keywords: Laccaria bicolor; Picea glauca; cell hydraulic conductivity; mycorrhizal fungal aquaporins; plasma membrane intrinsic protein; root hydraulic conductivity; water transport