title: First cloning and characterization of two functional aquaporin genes from an arbuscular mycorrhizal fungus Glomus intraradices.
abstract: Arbuscular mycorrhizal (AM) symbiosis is known to stimulate plant drought tolerance. However, the molecular basis for the direct involvement of AM fungi (AMF) in plant water relations has not been established. Two full-length aquaporin genes, namely GintAQPF1 and GintAQPF2, were cloned by rapid amplification of cDNA 5'- and 3'-ends from an AMF, Glomus intraradices. Aquaporin localization, activities and water permeability were examined by heterologous expression in yeast. Gene expression during symbiosis was also analyzed by quantitative real-time polymerase chain reaction. GintAQPF1 was localized to the plasma membrane of yeast, whereas GintAQPF2 was localized to both plasma and intracellular membranes. Transformed yeast cells exhibited a significant decrease in cell volume on hyperosmotic shock and faster protoplast bursting on hypo-osmotic shock. Polyethylene glycol (PEG) stimulated, but glycerol inhibited, the aquaporin activities. Furthermore, the expression of the two genes in arbuscule-enriched cortical cells and extraradical mycelia of maize roots was also enhanced significantly under drought stress. GintAQPF1 and GintAQPF2 are the first two functional aquaporin genes from AMF reported to date. Our data strongly support potential water transport via AMF to host plants, which leads to a better understanding of the important role of AMF in plant drought tolerance.
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
authors.forename: Ya-Jun
authors.initials: YJ
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
authors.forename: Zhi-Peng
authors.initials: ZP
authors.lastname: Hao
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute of Plant Nutrition and Resources, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China.
authors.forename: You-Shan
authors.initials: YS
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
authors.forename: Bao-Dong
authors.initials: BD
authors.lastname: Chen
mesh_terms: D020346:Aquaporins / Q000235:genetics*; D002118:Calcium / Q000378:metabolism; D003001:Cloning, Molecular; D015169:Colony Count, Microbial; D019295:Computational Biology; D055864:Droughts; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005800:Genes, Fungal / Q000235:genetics*; D055137:Glomeromycota / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D025282:Mycelium / Q000235:genetics; D038821:Mycorrhizae / Q000235:genetics* / Q000254:growth & development; D009997:Osmotic Pressure; D010802:Phylogeny; D010843:Pichia / Q000254:growth & development / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000382:microbiology; D021381:Protein Transport / Q000235:genetics; D011522:Protons; D011523:Protoplasts / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics; D014170:Transformation, Genetic; D014867:Water / Q000378:metabolism; D003313:Zea mays / Q000235:genetics / Q000382:microbiology
chemical_list: D020346:Aquaporins; D005656:Fungal Proteins; D011522:Protons; D014867:Water; D002118:Calcium