Bergman K, Gulash-Hoffee M, Hovestadt R E, Larosiliere R C, Ronco P G, Su L
Department of Biology, Northeastern University, Boston, Massachusetts 02115.
J Bacteriol. 1988 Jul;170(7):3249-54. doi: 10.1128/jb.170.7.3249-3254.1988.
Wild-type and nonchemotactic mutant strains of Rhizobium meliloti were tested for attraction to localized sites on alfalfa roots and for attraction to numerous small molecules, including sugars, amino acids, and two fractions derived from alfalfa root extracts. Four strains (carrying mutations che-6, che-11, che-12, and che-26) lost all responses and were classified as generally nonchemotactic mutants. One strain (carrying mutation che-7) lost responses to a group of structurally unrelated amino acids but retained all other responses and was classified as a putative sensory transducer mutant. Two strains (carrying mutations che-1 and che-3) lost responses to all the amino acids and sugars tested but retained normal responses to localized sites on roots and to the root fractions. These two mutant strains could not be classified according to the generally accepted model for a sensory pathway, derived from studies of enteric bacteria, and provided evidence for a dual chemotaxis pathway in R. meliloti.
对苜蓿中华根瘤菌的野生型和非趋化突变菌株进行了测试，检测它们对苜蓿根上局部位点的趋化性以及对多种小分子的趋化性，这些小分子包括糖类、氨基酸以及从苜蓿根提取物中得到的两个组分。四个菌株（携带che - 6、che - 11、che - 12和che - 26突变）失去了所有反应，被归类为一般非趋化突变体。一个菌株（携带che - 7突变）失去了对一组结构不相关氨基酸的反应，但保留了所有其他反应，被归类为假定的感觉转导突变体。两个菌株（携带che - 1和che - 3突变）失去了对所有测试氨基酸和糖类的反应，但对根上局部位点和根组分仍保持正常反应。这两个突变菌株无法根据源自对肠道细菌研究的、被广泛接受的感觉通路模型进行分类，为苜蓿中华根瘤菌中的双趋化通路提供了证据。
