Abstract
Breakdown of plant polysaccharides by root colonising bacteria can provide them with new carbon sources. Within the genus Azospirillum, breakdown of pectin (and polygalacturonic acid) is best documented for A. irakense. From a gene library of A. irakense KBC1 we have isolated several cosmid clones that express polygalacturonase and pectate lyase activity in E. coli and A. brasilense. Genes encoding these enzymes appear to be closely linked in the A. irakense genome.
Furthermore we introduced the alpha-amylase gene of Streptomyces venezuelae into A. brasilense to study heterologous gene expression. The gene was found to be expressed from its own promoter in A. brasilense, and the transconjugants were able to hydrolyse soluble starch. As a side effect we observed that these transconjugants were also able to use additional carbohydrates as a carbon source, compared to the wild type strain. Currently we are testing several possibilities explaining this phenomenon.
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© 1995 Springer-Verlag Berlin Heidelberg
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Keijers, V., Dobbelaere, S., Bekri, M.A., Vanderleyden, J. (1995). Biodegradation of polysaccharides by Azospirillum . In: Fendrik, I., del Gallo, M., Vanderleyden, J., de Zamaroczy, M. (eds) Azospirillum VI and Related Microorganisms. NATO ASI Series, vol 37. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-79906-8_9
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DOI: https://doi.org/10.1007/978-3-642-79906-8_9
Publisher Name: Springer, Berlin, Heidelberg
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