Transcriptome during autoregulation of mycorrhization in soybean

The autoregulation of mycorrhization (AOM) describes a plant regulatory mechanism that limits the number of infection events by arbuscular mycorrhizal fungi. The key signal mediator is a receptor kinase (GmNARK) that acts in the shoots. Early signals of the mycorrhizal symbiosis induce a root-derived signal that activates GmNARK in the shoot finally leading to a systemic repression of subsequent infections in the root. So far, less is known about the signals down-stream of GmNARK. To find genes regulated by GmNARK in a mycorrhiza-dependent as well as in a mycorrhiza-independent manner, we used the Affymetrix GeneChip for soybean. In general, mycorrhizal root systems consist of both colonized and non-colonized, but autoregulated roots. To physically separate those two root types for transcript analysis of specifically regulated genes, we used the split-root system. Transcript profiling during AOM was done with material of Bragg wild-type and of the nark mutant nts1007, either non-inoculated or partially inoculated with the mycorrhizal fungus Rhizophagus irregularis (formerly Glomus intraradices). Wild-type and nark mutants were inoculated with R. irregularis on one half of the root-systems (root-parts "A") only. The remaining half of the root-systems stayed non-infected (root-parts "B"). Corresponding controls stayed completely non-infected. Gene expression was analyzed in inoculated root-parts, non-inoculated root-parts and shoots of three individual plants per treatment. ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Sara Schaarschmidt. The equivalent experiment is GM53 at PLEXdb.]

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Schaarschmidt S, Gresshoff PM, Hause B