Inside arbuscular mycorrhizal roots-Molecular probes to understand the symbiosis
Daniel Ruzicka, Srikar Chamala, Felipe H. Barrios-Masias, Francis Martin, Sally Smith, Louise E. Jackson, W. Brad Barbazuk, and Daniel P. Schachtman
07 January 2013, The Plant Genome 6(2): 1-13; doi: 10.3835/plantgenome2012.06.0007
Associations between arbuscular mycorrhizal (AM) fungi and plants are an ancient and wide spread plant microbe symbioses. Most land plants can associate with this specialized group of soil fungi (in the Glomeromycota), which enhance plant nutrient uptake in return for carbon derived from plant photosynthesis. Elucidating the mechanisms involved in the symbiosis between obligate symbionts such as AM fungi and plant roots is challenging because AM fungal transcripts in roots are in low abundance and reference genomes for the fungi have not been available. A deep sequencing metatranscriptomics approach was applied to a wild-type tomato and a tomato mutant incapable of supporting a functional AM symbiosis, revealing novel AM fungal and microbial transcripts expressed in colonized roots. We confirm transcripts known to be mycorrhiza-associated, and report the discovery of more than 500 AM fungal and novel plant transcripts associated with mycorrhizal tomato roots including putative zinc, iron, aquaporin, and carbohydrate transporters, as well as mycorrhizal-associated alternative gene splicing. This analysis provides a fundamental step towards identifying the molecular mechanisms of mineral and carbohydrate exchange during the symbiosis. The utility of this metatranscriptomic approach to explore an obligate biotrophic interaction is illustrated, especially as it relates to agriculturally-relevant biological processes.
Ruzicka, Daniel, Chamala, Srikar, Barrios-Masias, Felipe H., Martin, Francis, Smith, Sally, Jackson, Louise E., Barbazuk, W. Brad, and Schachtman Daniel P. Inside Arbuscular Mycorrhizal Roots â Molecular Probes to Understand the Symbiosis. Plant Genome 6(2): 1-13.