Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Xu, Hao [1], Zwiazek, Janusz J. [1], Cooke, Janice E. K. [2].

Laccaria bicolor MIPs contribute to root water transport and basidiocarp development in ectomycorrhizal association with Picea glauca.

Ectomycorrhizal (ECM) fungi and associated plants exchange nutrients, water and carbohydrates during their symbiotic interactions. The importance of Major Intrinsic Protein (MIP) family to transport of water and small neutral molecules has been extensively studied in plants, but relatively little understood in fungi. This study investigated the roles of fungal MIPs of ECM basidiomycete Laccaria bicolor in two important mycorrhizal processes – ECM root water transport and basidiocarp formation. The L. bicolor MIP JQ585595 demonstrated high water transport capacity in Xenopus oocyte swelling assay, whereas JQ585592 was a functional channel for CO₂, NO and H₂O₂ in yeast expression assays. Transcript profiles showed fungal MIP upregulation in ECM root tips of white spruce (Picea glauca), and significant regulation of MIPs during the basidiocarp initiation and development. Mycorrhization with L. bicolor increased shoot water potential, net photosynthetic rates and root hydraulic conductivity in P. glauca seedlings. Seedling photosynthetic rate further increased when the associated L. bicolor produced basidiocarps. When P. glauca was colonized by L. bicolor transgenic strains that overexpressed JQ585595, it led to higher root hydraulic conductivity and higher expression of the MIP gene PIP1;1 in P. glauca roots. The significant involvement of MIPs in ECM water transport and basidiocarp growth, highlights that fungal MIPs are of great importance to some of the fundamental processes in ECM symbiont fungi and plants. Understanding their roles may help to delineate ECM functions in forest water and carbon cycling.

1 - University of Alberta, Renewable Resources, 447 Earth Science Building 116 ST 85 AVE, Edmonton, AB, T6G2E3, Canada
2 - University of Alberta, Biological Sciences, 5-119 CCIS 116 St 85 Ave, Edmonton, AB, T6G2E9, Canada

Keywords:
Aquaporin
Basidiocarp
ectomycorrhizal fungi
Major intrinsic protein 
Root water transport .

Presentation Type: Oral Paper:Papers for Topics
Session: 36
Location: Salon 5/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 10:45 AM
Number: 36011
Abstract ID:461
Candidate for Awards:None