Journal Article

Large-Scale Analysis of Gene Expression Profiles during Early Stages of Root Nodule Formation in a Model Legume, <i>Lotus japonicus</i>

Hiroshi Kouchi, Kenshiro Shimomura, Shingo Hata, Atsuko Hirota, Guo-Jiang Wu, Hirotaka Kumagai, Shigeyuki Tajima, Norio Suganuma, Akihiro Suzuki, Toshio Aoki, Makoto Hayashi, Tadashi Yokoyama, Takuji Ohyama, Erika Asamizu, Chikara Kuwata, Daisuke Shibata and Satoshi Tabata

in DNA Research

Published on behalf of Kazusa DNA Research Institute

Volume 11, issue 4, pages 263-274
Published in print January 2004 | ISSN: 1340-2838
Published online January 2004 | e-ISSN: 1756-1663 | DOI:

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Gene expression profiles during early stages of formation of symbiotic nitrogen-fixing nodules in a model legume Lotus japonicus were analyzed by means of a cDNA array of 18,144 non-redundant expressed sequence tags (ESTs) isolated from L. japonicus. Expression of a total of 1,076 genes was significantly accelerated during the successive stages that represent infection of Mesorhizobium loti, nodule primordium initiation, nodule organogenesis, and the onset of nitrogen fixation. These include 32 nodulin and nodulinhomolog genes as well as a number of genes involved in the catabolism of photosynthates and assimilation of fixed nitrogen that were previously known to be abundantly expressed in root nodules of many legumes. We also identified a large number of novel nodule-specific or enhanced genes, which include genes involved in many cellular processes such as membrane transport, defense responses, phytohormone synthesis and responses, signal transduction, cell wall synthesis, and transcriptional regulation. Notably, our data indicate that the gene expression profile in early steps of Rhizobium-legume interactions is considerably different from that in subsequent stages of nodule development. A number of genes involved in the defense responses to pathogens and other stresses were induced abundantly in the infection process, but their expression was suppressed during subsequent nodule formation. The results provide a comprehensive data source for investigation of molecular mechanisms underlying nodulation and symbiotic nitrogen fixation.

Keywords: cDNA array; nitrogen fixation; nodulin; Rhizobium-plant interactions

Journal Article.  0 words. 

Subjects: Genetics and Genomics

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