Plant & Animal Genome IX Conference Plant & Animal Genome IX Conference
Poster: Sequencing & EST
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The arbuscular mycorrhizae (AM) are mutualistic associations formed between fungi from the order, Glomales and most angiosperms, including many of the agriculturally significant crop species. Despite the widespread occurrence of the association, its ecological significance and its potential importance in agriculture, relatively little is known at the molecular level, about the development, functioning and regulation of the symbiosis. The model legume Medicago truncatula has many advantages for molecular genetic research including ongoing efforts to develop a suite of genomic tools. To study the genes from M. truncatula that are expressed during the development of the AM symbiosis, a cDNA library was prepared from M. truncatula roots colonized with the AM fungus, Glomus versiforme. EST sequencing of the clones from this library has been conducted and 3259 ESTs have been deposited at NCBI . Preliminary clustering analyses performed by TIGR indicates that 35 clusters of ESTs are unique to the M. truncatula / G. versiforme library. Macro-arrays containing 5,000 clones spotted in duplicate on GeneScreen Plus « membrane in a æ16 blocks of 96Æ format have been hybridized with 33 P labeled first-strand cDNA probes prepared from M. truncatula /G. versiforme roots and mock-inoculated M. truncatula roots. The hybridization signal was captured on PhosphorImager screens and analyzed with ImageQuant software (Molecular Dynamics). Genes showing altered transcript levels with expression ratios of greater than 2 were identified. Detailed analyses of the temporal expression profiles of these genes during development of the mycorrhiza have been initiated.