IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
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17 th <strong>International</strong> Congress on <strong>Nitrogen</strong> <strong>Fixation</strong><br />
Fremantle, Western Australia<br />
27 November – 1 December 2011<br />
Session Details: Wednesday 30 November 2011<br />
Plenary Session 6<br />
1330 - 1500<br />
Authors: Xi Chen, Theja Shidore, Theresa Dinse, Sabrina Gemmer, Thomas Hurek and Barbara<br />
Reinhold-Hurek<br />
Department of Microbe-Plant Interactions, University of Bremen, Postfach 33 04 40,<br />
28334 Bremen.<br />
Presentation Title: Functional genomic analyses of endophyte – rice Interactions<br />
Presentation Time: 1430 -1500<br />
Azoarcus sp. strain BH72, a mutualistic endophyte of rice and other grasses, is of agro-biotechnological interest<br />
because it supplies fixed nitrogen to its host and colonises plants in remarkably high numbers without eliciting<br />
disease symptoms. This raises the question of mechanisms of compatible interactions between host and<br />
bacterium. The complete genome of strain BH72 was sequenced (1), and the rice genome is also available. This<br />
allows application of functional genomic analyses of both partners during interaction. For symbiotic interactions<br />
such with rhizobia and arbuscular mykorrhiza (AM), common plant signalling cascades are now well<br />
characterized. The results of our analysis of differential gene expression in Azoarcus-infected rice roots and<br />
mutational analyses suggest that the cascades are not operating during endophytic interactions. Nevertheless,<br />
transcriptomic analysis demonstrated that both partners show extensive metabolic adaptations during endophytic<br />
interaction. Transcriptomic analyses were carried out for both partners, rice as well as exudates-exposed<br />
Azoarcus sp. They allowed identification of candidate genes which were shown by mutational analysis to be<br />
required for optimal rhizosphere fitness in Azoarcus sp.<br />
(1) Krause et al. 2006. Genomic insights into the lifestyle of the mutualistic, N2-fixing grass endophyte Azoarcus<br />
sp. strain BH72. Nature Biotechnol. 24: 1385-1391.<br />
81<br />
2011