title: Laccaria bicolor aquaporin LbAQP1 is required for Hartig net development in trembling aspen (Populus tremuloides).
abstract: The development of ectomycorrhizal associations is crucial for growth of many forest trees. However, the signals that are exchanged between the fungus and the host plant during the colonization process are still poorly understood. In this study, we have identified the relationship between expression patterns of Laccaria bicolor aquaporin LbAQP1 and the development of ectomycorrhizal structures in trembling aspen (Populus tremuloides) seedlings. The peak expression of LbAQP1 was 700-fold higher in the hyphae within the root than in the free-living mycelium after 24 h of direct interaction with the roots. Moreover, in LbAQP1 knock-down strains, a non-mycorrhizal phenotype was developed without the Hartig net and the expression of the mycorrhizal effector protein MiSSP7 quickly declined after an initial peak on day 5 of interaction of the fungal hyphae with the roots. The increase in the expression of LbAQP1 required a direct contact of the fungus with the root and it modulated the expression of MiSSP7. We have also determined that LbAQP1 facilitated NO, H2 O2 and CO2 transport when heterologously expressed in yeast. The report demonstrates that the L. bicolor aquaporin LbAQP1 acts as a molecular signalling channel, which is fundamental for the development of Hartig net in root tips of P. tremuloides.
authors: Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada.
authors: Alfonso
authors: A
authors: Navarro-RóDenas
authors: Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada.
authors: Hao
authors: H
authors: Xu
authors: Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernal, Provincia de Buenos Aires, B1876BXD, Argentina.
authors: Minna
authors: M
authors: Kemppainen
authors: Laboratorio de Micología Molecular, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bernal, Provincia de Buenos Aires, B1876BXD, Argentina.
authors: Alejandro G
authors: AG
authors: Pardo
authors: Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada.
authors: Janusz J
authors: JJ
authors: Zwiazek
mesh_terms: D020346:Aquaporins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001692:Biological Transport; D002245:Carbon Dioxide / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D055785:Gene Knockdown Techniques; D006861:Hydrogen Peroxide / Q000378:metabolism; D055399:Laccaria / Q000378:metabolism / Q000502:physiology*; D038821:Mycorrhizae; D009569:Nitric Oxide / Q000378:metabolism; D010641:Phenotype; D018517:Plant Roots / Q000378:metabolism; D032107:Populus / Q000378:metabolism / Q000382:microbiology*
chemical_list: D020346:Aquaporins; D005656:Fungal Proteins; D002245:Carbon Dioxide; D009569:Nitric Oxide; D006861:Hydrogen Peroxide
keywords: MiSSP7; carbon dioxide; ectomycorrhizae; fungal aquaporins; hydrogen peroxide; nitric oxide