|Samac, Deborah - Debby|
Submitted to: International Conference on Legume Genomics and Genetics
Publication Type: Abstract Only
Publication Acceptance Date: 12/7/2008
Publication Date: 12/7/2008
Citation: Harrison, M.J., Zhang, Q., Levy, J.G., Jung, J.K., Hong, J.J., Mondo, S.J., Foster-Hartnett, D., Samac, D.A., Starker, C.G., Lenz, P.A., Farell, M.L., Gantt, J.S. 2008. Identification of genes controlling development of arbuscules in AM symbiosis [abstract]. IV International Conference on Legume Genomics and Genetics, December 7-12, 2008, Puerto Vallarta, Mexico. Abstract No. L61. p. 38.
Technical Abstract: Most vascular flowering plants have the capacity to form mutualistic symbioses with arbuscular mycorrhizal (AM) fungi. These associations develop in the roots where the fungus delivers phosphate to the root cortical cells and receives carbon from its plant host. During the symbiosis, the fungus proliferates in the root apoplast and colonizes the cortical cells where it differentiates to create highly branched hyphae called arbuscules. Arbuscule development requires the active participation of the plant cell and as each arbuscule develops, the cortical cell envelopes the hyphal branches in a novel membrane, the peri-arbuscular membrane. The resulting arbuscule-cortical cell interface is the site of phosphate transfer to the plant cell. Using a legume, Medicago truncatula, and an AM fungus, Glomus versiforme, we have taken both forward and reverse genetics approaches to identify M. truncatula genes required for development of the arbuscule-cortical cell interface. Via a forward genetic screen, we identified STR, a mutant in which arbuscule formation is arrested. Positional cloning of STR will be discussed. Transcript profiling coupled with spatial expression analyses have enabled the identification of M. truncatula genes whose expression coincides with arbuscule development. RNAi screens are underway to evaluate their roles in arbuscule development. Recent progress with the reverse genetic screen will be discussed.