A rice calcium-dependent protein kinase is expressed in cortical root cells during the presymbiotic phase of the arbuscular mycorrhizal symbiosis

BMC Plant Biology

Research Article

Lidia Campos-Soriano¹  Blanca San Segundo¹  Jorge Gómez-Ariza²  Paola Bonfante² 

[1] Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB. Department of Molecular Genetics, Campus UAB, Edifici CRAG, 08193, Bellaterra (Cerdanyola del Vallès), Barcelona, Spain;Department of Plant Biology, University of Torino and Istituto per la Protezione delle Piante - CNR. Sezione di Torino, Viale P.A. Mattioli 25, 10125, Torino, Italy;

关键词: Arbuscular Mycorrhizal;    Rice Root;    Green Fluorescent Protein Gene;    Onion Epidermal Cell;    Laser Microdissection;   

DOI  :  10.1186/1471-2229-11-90

 received in 2011-02-18, accepted in 2011-05-19,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundThe arbuscular mycorrhizal (AM) symbiosis consists of a mutualistic relationship between soil fungi and roots of most plant species. This association provides the arbuscular mycorrhizal fungus with sugars while the fungus improves the uptake of water and mineral nutrients in the host plant. Then, the establishment of the arbuscular mycorrhizal (AM) symbiosis requires the fine tuning of host gene expression for recognition and accommodation of the fungal symbiont. In plants, calcium plays a key role as second messenger during developmental processes and responses to environmental stimuli. Even though calcium transients are known to occur in host cells during the AM symbiosis, the decoding of the calcium signal and the molecular events downstream are only poorly understood.ResultsThe expression of seventeen Calcium-dependent Protein Kinase (CPK) genes representative of the four distinct phylogenetic groups of rice CPKs was monitored during the presymbiotic phase of the AM symbiosis. Among them, OsCPK18 and OsCPK4, were found to be transcriptionally activated in response to inoculation with the AM fungus Glomus intraradices.OsCPK18 and OsCPK4 gene expression was also up-regulated by fungal-produced diffusible molecules. Laser microdissection revealed expression of OsCPK18 in cortical cells, and not in epidermal cells of G. intraradices-inoculated rice roots, suggesting a preferential role of this gene in the root cortex. Moreover, a plasma membrane localization of OsCPK18 was observed by transient expression assays of green fluorescent protein-tagged OsCPK18 in onion epidermal cells. We also show that the myristoylation site of the OsCPK18 N-terminus is required for plasma membrane targeting.ConclusionThe rapid activation of OsCPK18 expression in response to AM inoculation, its expression being also induced by fungal-secreted signals, together with the observed plasma membrane localization of OsCPK18, points to a role for OsCPK18 in perception of the AM fungus. The OsCPK18 gene might be considered as a marker for the presymbiotic phase of the symbiotic process. These findings provide a better understanding of the signaling mechanisms operating during the AM symbiosis and will greatly facilitate their molecular dissection.

【 授权许可】

Unknown   
© Campos-Soriano et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.