Variation in nitrate metabolism in biovars of Pseudomonas solanacearum |
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Authors: | A.C. Hayward, &dagger ,H.M. El-Nashaar,&dagger ,Ursula,Nvdegger&dagger Liliam De, Lindo&dagger |
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Affiliation: | †Department of Microbiology, University of Queensland, St. Lucia 4067, Queensland, Australia;†Department of Plant Pathology, International Potato Center (CIP), Apartado 5969, Lima, Peru |
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Abstract: | A collection of 327 strains of Pseudomonas solanacearum , representing five biovars, was divisible into three groups on the basis of differences in nitrate metabolism. Nine strains (2.8%), of which seven were biovar 2 from bacterial wilt of potato, were nitrate reduction-deficient and failed to produce nitrite from nitrate by either of two methods of detection in five different media. A second group of 231 strains, comprising biovars 1 and 2 and a single biovar 3 strain, produced nitrite from nitrate and grew vigorously in the presence of nitrate under anaerobic conditions but were deficient in ability to denitrify. A third group comprising 57 strains of biovar 3, 28 of biovar 4 and one each of biovar 2 and 5 produced nitrite from nitrate and gave profuse growth and gas production from nitrate under anaerobic conditions. However, production of gas from nitrate (denitrification) was not a consistently reproducible property in some of the media tested. Gas production results were most reproducible when a semi-solid succinate/nitrate or glycerol/nitrate medium was used. Serial passage of four nitrate reduction-deficient isolates in nitrate medium did not restore ability to reduce nitrate. |
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