drates. Acid slowly formed from xylose and Rods. Motile by means of peritrichous arabinose. flagella. Bacteroids club-shaped and Aerobic. branched. Gram-negative. Optimum temperature, 25° C. Growth on mannitol agar is fairly rapid. Source: Isolated from root nodules on The streak is raised, glistening, opaque, Soja max (soy bean). pearly white, butyrous. Considerable gum Habitat : Widely distributed in soils where is formed, soy beans are grown. Acid from glucose, galactose, mannose and sucrose. 6. Rhizobium meliloti Dangeard, 1926. Aerobic. (Le Botaniste, Sdr. 16, 1926, 194.) Optimum temperature, 25° C. me.li.lo'ti. Gr. noun vieli honey; Gr. Source: Isolated from root nodules of noun lotus the lotus; Gr. noun melilotus Melilotus (sweet clover), Medicago and Tri- melilot or sweet clover; M.L. fem.n. Meli- gonella. lotus generic name of sweet clover; M.L. Habitat: Widely distributed in soils in gen. noun meliloti of Melilotus. which these legumes grow. Genus II. Agrobacterium Conn, 194^.* (Jour. Bact., U, 1942, 359.) Ag.ro. bac.te'ri.um. Gr. noun agrus a field; Gr. dim.neut.n. bacterium a small rod; M.L neut.n. Agrobacterium field rodlet or bacterium. Small, short rods which are typically motile by means of 1 to 4 peritrichous flagella (if only one flagellum, lateral attachment is as common as polar). Ordinarily Gram-nega- tive. On ordinary culture media they do not produce visible gas nor sufficient acid to be detectable by litmus. In synthetic media, enough CO2 may be produced to show acid with brom thymol blue or sometimes with brom cresol purple. Gelatin is either very slowly li- quefied or not at all. Free nitrogen cannot be fixed, but other inorganic forms of nitrogen (ni- trates or ammonium salts) can ordinarily be utilized. Optimum temperature, between 25° and 30°C. Found in soil, in plant roots in the soil or in the stems of plants where they pro- duce hypertrophies; occasionally from marine sources. The type species is Agrobacterium tumefaciens (Smith and Townsend) Conn. Key to the species of genus Agrobacterium. I. Plant pathogens. A. Nitrites produced from nitrates, sometimes only to a slight extent. 1. Produce galls on angiosperms. a. Indole production slight. 1. Agrobacterium tumefaciens. aa. Indole not produced. 2. Agrobacteriiim gypsophilae. 2. Produces galls on gymnosperms. 3. Agrobacterium pseudotsugae. B. Nitrites not produced from nitrates. 1. Pathogenic to apples. 4. Agrobacterium rhizogenes. 2. Pathogenic to raspberries and blackberries. 5. Agrobacterium rubi.
- Originally prepared by Prof. H. J. Conn, New York State Experiment Station, Cornell
University, Geneva, New York, September, 1943; revised by Prof. Walter H. Burkholder, Cornell University, Ithaca, New York, July, 1954.
