Kidambi, Saranga P.Sundin, George W.Palmer, David A.Chakrabarty, Ananda M.Bender, Carol L.2015-10-162015-10-161995-06Kidambi, S. P., Sundin, G. W., Palmer, D. A., Chakrabarty, A. M., & Bender, C. L. (1995). Copper as a signal for alginate synthesis in Pseudomonas syringae pv. syringae. Applied and Environmental Microbiology, 61(6), 2172-2179. https://doi.org/10.1128/aem.61.6.2172-2179.1995http://hdl.handle.net/20.500.14446/19763Plant-associated pseudomonads are commonly exposed to copper bactericides, which are applied to reduce the disease incidence caused by these bacteria. Consequently, many of these bacteria have acquired resistance or tolerance to copper salts. We recently conducted a survey of 37 copper-resistant (Cu^r) Pseudomonas spp., including P. cepacia, P. fluorescens, P. syringae, and P. viridiflava, and found that a subset of the P. syringae strains showed a dramatic increase in exopolysaccharide (EPS) production on mannitol-glutamate medium containing CuSO4 at 250 mg/ml. A modified carbazole assay indicated that the EPS produced on copperamended media contained high levels of uronic acids, suggesting that the EPS was primarily alginic acid. Uronic acids extracted from selected strains were further confirmed to be alginate by demonstrating their sensitivity to alginate lyase and by descending paper chromatography following acid hydrolysis. Subinhibitory levels of arsenate, cobalt, lithium, rubidium, molybdenum, and mercury did not induce EPS production, indicating that alginate biosynthesis is not induced in P. syringae cells exposed to these heavy metals. A 200-kb plasmid designated pPSR12 conferred a stably mucoid phenotype to several P. syringae recipients and also increased their resistance to cobalt and arsenate. A cosmid clone constructed from pPSR12 which conferred a stably mucoid phenotype to several P. syringae strains but not to Pseudomonas aeruginosa was obtained. Results obtained in this study indicate that some of the signals and regulatory genes for alginate production in P. syringae differ from those described for alginate production in P. aeruginosa.application/pdfThis material has been previously published. In the Oklahoma State University Library's institutional repository this version is made available through the open access principles and the terms of agreement/consent between the author(s) and the publisher. The permission policy on the use, reproduction or distribution of the material falls under fair use for educational, scholarship, and research purposes. Contact Digital Resources and Discovery Services at lib-dls@okstate.edu or 405-744-9161 for further information.10.1128/aem.61.6.2172-2179.1995Article