Floral and Nursery Plants Research Unit, United States National Arboretum, U.S. Dept. of Agriculture-Agricultural Research Service, Beltsville, MD 20705, USA.
J Microbiol Methods. 2012 Feb;88(2):271-4. doi: 10.1016/j.mimet.2011.12.007. Epub 2011 Dec 19.
Race 3, biovar 2 strains of Ralstonia solanacearum are quarantined pathogens in Europe and Canada and Select Agent pathogens in the United States. The biovar classification of R. solanacearum strains is based on their biochemical abilities to utilize a carbohydrate panel. The standard biovar test uses bromothymol blue as a pH indicator in 15 ml culture tubes containing 3 to 5 ml of test media, and takes weeks to complete at 24 or 28 °C. We improved the biovar test by using phenol red as a pH indicator that changes color at a higher pH when a carbohydrate is utilized. We also conducted the test at 32 °C in 0.2 ml of 8-tube strips that reduced the medium needed by at least 20 fold. Using the improved test, biovars of R. solanacearum strains can be determined in 4 days when a panel of seven carbohydrates is used including glucose, trehalose, mannitol, sorbitol, dulcitol, maltose and cellobiose. To differentiate biovars 1, 2, 3 and 4, the test can be further simplified and completed in 3 days using a panel of four carbohydrates containing glucose, trehalose, maltose and dulcitol, significantly saving money, space and time.
Race 3、biovar 2 型青枯雷尔氏菌是欧洲和加拿大的检疫性有害生物，也是美国的 Select Agent 有害生物。青枯雷尔氏菌菌株的生物变种分类是基于它们利用碳水化合物组的生化能力。标准的生物变种测试使用溴百里酚蓝作为 pH 指示剂，在含有 3 至 5 毫升测试培养基的 15 毫升培养管中进行，在 24 或 28°C 下需要数周时间才能完成。我们通过使用苯酚红作为 pH 指示剂来改进生物变种测试，当碳水化合物被利用时，它会在更高的 pH 值下改变颜色。我们还在 0.2 毫升 8 管条带中在 32°C 下进行测试，这至少减少了 20 倍所需的培养基。使用改良的测试，当使用包括葡萄糖、海藻糖、甘露醇、山梨糖醇、肌醇、麦芽糖和纤维二糖在内的七种碳水化合物的面板时，R. solanacearum 菌株的生物变种可以在 4 天内确定。为了区分生物变种 1、2、3 和 4，可以进一步简化测试并在 3 天内使用包含葡萄糖、海藻糖、麦芽糖和肌醇的四种碳水化合物面板完成，这显著节省了金钱、空间和时间。
