Split-root study of autoregulation of nodulation in the model legume Lotus japonicus
- 331 Downloads
We used a split-root system to determine the timing for induction of the autoregulation of nodulation (AUT) in Lotus japonicus (Regel) Larsen after inoculation with Mesorhizobium loti. The signal took at least five days for full induction of AUT and inhibition of infection thread formation. Strain ML108 (able to nodulate but unable to fix nitrogen) induced full AUT, but ML101 (unable to nodulate or to fix nitrogen) did not induce autoregulation. These results indicate that Nod factor-producing strains induce AUT, but that the nitrogen fixed by rhizobia and supplied to the plant as ammonia does not elicit the AUT in L. japonicus.
KeywordsLotus japonicus Autoregulation Nodulation Symbiosis Nitrogen fixation Split-root system
Lotus japonicus Miyakojima MG-20 seeds were provided by University of Miyazaki, through the National Bio-Resource Project (NBRP) of the MEXT, Japan. This work was supported in part by the Special Coordination Funds for Promoting Science and Technology from the Ministry of Education, Culture, Sports, Science and Technology in Japan.
- Carroll BJ, Gresshoff PM (1983) Nitrate inhibition of nodulation and nitrogen fixation in white clover. Z Pflanzenphysiol Bd 110:77–88Google Scholar
- Nakatsukasa-Akune M, Yamashita K, Shimoda Y, Uchiumi T, Abe M, Aoki T, Kamizawa A, Ayabe S, Higashi S, Suzuki A (2005) Suppression of root nodule formation by artificial expression of the TrEnodDR1 (coat protein of white clover cryptic virus 1) gene in Lotus japonicus. Mol Plant Microbe Interact 18:1069–1080PubMedCrossRefGoogle Scholar
- Oka-Kira E, Tateno K, Miura K, Haga T, Hayashi M, Harada K, Sato S, Tabata S, Shikazono N, Watanabe Y, Fukuhara I, Nagata T, Kawaguchi M (2005) klavier (klv), a novel hypernodulation mutant of Lotus japonicus affected in vascular tissue organization and floral induction. Plant J 44:505–515PubMedCrossRefGoogle Scholar
- Sagan M, Duc G (1996) Sym28 and Sym29, two new genes involved in regulation of nodulation in pea (Pisum sativum L.). Symbiosis 20:229–245Google Scholar