Root exudate-stimulated RNA accumulation in the arbuscular mycorrhizal fungus Gigaspora rosea

GR24, a Synthetic Analog of Strigolactones, Stimulates the Mitosis and Growth of the Arbuscular Mycorrhizal FungusGigaspora roseaby Boosting Its Energy Metabolism

“…It has been shown previously that the semipurified root exudate fraction (the so-called branching factor; Nagahashi and Douds, 1999Buée et al, 2000) affects the expression of genes with a mitochondrial function (Tamasloukht et al, 2003(Tamasloukht et al, , 2007. The rapid (within minutes) mitochondrial activation of G. rosea by GR24 that we observed suggests that it does not rely on enhanced transcription.…”

“…Although, a previously isolated root exudate fraction, and here the synthetic strigolactone (GR24), have been shown to induce similar effects on mitochondrial changes (Tamasloukht et al, 2003;Besserer et al, 2006), the results on gene expression are different. The rapid up-regulation of several genes observed in response to root exudates (Tamasloukht et al, 2003(Tamasloukht et al, , 2007 suggests that other, yet unknown, molecules act in synergy or in parallel with strigolactones (Nagahashi and Douds, 2007).…”

2 Molecular Approaches to Arbuscular Mycorrhiza Functioning

“…However, the first molecular signs of the developmental switch were immediate increases of NAD and ATP during the first 10 min after strigolactone application, indicating an activation of the energy metabolism (Besserer et al 2008). Induction of gene expression, in contrast, could be identified only after 1 h of stimulation with purified root exudates (Tamasloukht et al 2003(Tamasloukht et al , 2007. Most of the regulated genes identified in Gigaspora rosea 90 min after the stimulus were involved in mitochondrial functioning, indicating an increased respiration (Tamasloukht et al 2003).…”

“…The high induction of this gene could be necessary for the observed dark fixation of CO 2 and its transfer to oxalacetate (Bago et al 1999). Addition of root exudates also enhanced the expression of a proton-pumping ATPase (Tamasloukht et al 2007). The homologous gene GmHA5 in G. mosseae was previously shown to be expressed upon plant recognition (Requena et al 2003).…”

“…This has been confirmed by laser micro-dissected arbuscules where HA5 was shown to be induced (Balestrini et al 2007). The putative orthologue of HA5 in G. rosea is induced by root exudates (Tamasloukht et al 2007), which corresponds to exudate-stimulated ATPase activity and uptake of 32 P in germinating spores (Lei et al 1991). …”