Two Medicago truncatula Half-ABC Transporters Are Essential for Arbuscule Development in Arbuscular Mycorrhizal Symbiosis
- 1 May 2010
- journal article
- Published by Oxford University Press (OUP) in Plant Cell
- Vol. 22 (5), 1483-1497
- https://doi.org/10.1105/tpc.110.074955
Abstract
In the symbiotic association of plants and arbuscular mycorrhizal (AM) fungi, the fungal symbiont resides in the root cortical cells where it delivers mineral nutrients to its plant host through branched hyphae called arbuscules. Here, we report a Medicago truncatula mutant, stunted arbuscule (str), in which arbuscule development is impaired and AM symbiosis fails. In contrast with legume symbiosis mutants reported previously, str shows a wild-type nodulation phenotype. STR was identified by positional cloning and encodes a half-size ATP binding cassette (ABC) transporter of a subfamily (ABCG) whose roles in plants are largely unknown. STR is a representative of a novel clade in the ABCG subfamily, and its orthologs are highly conserved throughout the vascular plants but absent from Arabidopsis thaliana. The STR clade is unusual in that it lacks the taxon-specific diversification that is typical of the ABCG gene family. This distinct phylogenetic profile enabled the identification of a second AM symbiosis-induced half-transporter, STR2. Silencing of STR2 by RNA interference results in a stunted arbuscule phenotype identical to that of str. STR and STR2 are coexpressed constitutively in the vascular tissue, and expression is induced in cortical cells containing arbuscules. STR heterodimerizes with STR2, and the resulting transporter is located in the peri-arbuscular membrane where its activity is required for arbuscule development and consequently a functional AM symbiosis.Keywords
This publication has 77 references indexed in Scilit:
- Live-Cell Imaging Reveals Periarbuscular Membrane Domains and Organelle Location in Medicago truncatula Roots during Arbuscular Mycorrhizal SymbiosisPlant Physiology, 2009
- ABC transporters: the power to changeNature Reviews Molecular Cell Biology, 2009
- CYCLOPS, a mediator of symbiotic intracellular accommodationProceedings of the National Academy of Sciences, 2008
- Protein co-evolution, co-adaptation and interactionsThe EMBO Journal, 2008
- Differential and chaotic calcium signatures in the symbiosis signaling pathway of legumesProceedings of the National Academy of Sciences of the United States of America, 2008
- GR24, a Synthetic Analog of Strigolactones, Stimulates the Mitosis and Growth of the Arbuscular Mycorrhizal FungusGigaspora roseaby Boosting Its Energy MetabolismPlant Physiology, 2008
- A Medicago truncatula phosphate transporter indispensable for the arbuscular mycorrhizal symbiosisProceedings of the National Academy of Sciences of the United States of America, 2007
- A Diffusible Signal from Arbuscular Mycorrhizal Fungi Elicits a Transient Cytosolic Calcium Elevation in Host Plant CellsPlant Physiology, 2006
- Overexpression of an Arabidopsis thaliana ABC transporter confers kanamycin resistance to transgenic plantsNature Biotechnology, 2005
- Agrobacterium rhizogenes-Transformed Roots of Medicago truncatula for the Study of Nitrogen-Fixing and Endomycorrhizal Symbiotic AssociationsMolecular Plant-Microbe Interactions®, 2001