1Lehrstuhl für Genetik, Fakultät für Biologie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany; 2Lehrgebiet Molekulargenetik, Universität Hannover, Herrenhäuser Straße 2, D-30419 Hannover, Germany; 3International NRW Graduate School in Bioinformatics and Genome Research, Center for Biotechnology (CeBiTec), Bielefeld University, D-33594 Bielefeld Germany; 4Institute of Genome Research, Center for Biotechnology (CeBiTec), Bielefeld University, D-33594 Bielefeld, Germany
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Accepted 18 June 2004.
Transcriptome profiling based on cDNA array hybridizations and in silico screening was used to identify Medicago truncatula genes induced in both root nodules and arbuscular mycorrhiza (AM). By array hybridizations, we detected several hundred genes that were upregulated in the root nodule and the AM symbiosis, respectively, with a total of 75 genes being induced during both interactions. The second approach based on in silico data mining yielded several hundred additional candidate genes with a predicted symbiosis-enhanced expression. A subset of the genes identified by either expression profiling tool was subjected to quantitative real-time reverse-transcription polymerase chain reaction for a verification of their symbiosis-induced expression. That way, induction in root nodules and AM was confirmed for 26 genes, most of them being reported as symbiosis-induced for the first time. In addition to delivering a number of novel symbiosis-induced genes, our approach identified several genes that were induced in only one of the two root endo-symbioses. The spatial expression patterns of two symbiosis-induced genes encoding an annexin and a β-tubulin were characterized in transgenic roots using promoter-reporter gene fusions.
© 2004 The American Phytopathological Society