FAMILY RHIZOBIACEAE 



229 



Sources : Description made from ten 

 cultures isolated from hairy -root of apple 

 and other plants. 



Habitat: Pathogenic on apple, etc. 



3. Agrobacterium rubi (Hildebrand) 

 Starr and Weiss. {Phytomonas rubi 

 Hildebrand, Jour. Agr. Res., 61, 1940, 

 694; Bacterium rubi Hildebrand, ibid., 

 694; Pseudomonas rubi Hildebrand, ibid., 

 694; Banfield, Phytopath., 20, 1930, 123; 

 Pinckard, Jour. Agr. Res., 50, 1935, 933; 

 Starr and Weiss, Phytopath., 33, 1943, 

 316.) From Latin, rubus, blackberrj' 

 bush; M. L., Rubus, a generic name. 



Rods: 0.6 by 1.7 microns. Singly, in 

 pairs or short chains. IMotile with 1 to 4 

 flagella. Gram-negative. 



Gelatin : No liquefaction. 



Potato-mannitol-agar slants: Growth 

 slow, moderate, filiform, white to creamy- 

 white, with butyrous consistency later 

 becoming leathery. 



Broth: Turbid in 36 to 48 hours. 



Milk: A slight serum-zone, pink color, 

 acid and curd formed. 



Nitrites not produced from nitrates. 



Ferric ammonium citrate, uric acid, 

 oxamide, succinimide, 1-asparagine, 1- 

 tjTosine, 1-cystine, d-glutamic acid and 

 yeast extract can be used as a source of 

 nitrogen (Pinckard, loc. cit.). 



Hydrogen sulfide not formed. 



Indole not formed. 



Acid from glucose, d-galactose, d- 

 mannose, d-fructose, d-xylose, d-arabin- 

 ose, sucrose, and maltose. None from 

 lactose (Pinckard, loc. cit.). 



Starch not hydrolyzed. 



Optimum temperature 28°C. Mini- 

 mum 8°C. and maximum 36°C. (Pinck- 

 ard, loc. cit.). 



Distinctive characters. Differs from 

 Agrobacterium tumefaciens in that it 

 does not utilize nitrates, and grows much 

 more slowly on ordinary media. Infects 

 only members of the genus Rubus. Starr 

 and Weiss (Phytopath., 33, 1943, 317) 

 state that this species unlike Agrobac- 

 ferivm itimefaciens and Agrobacterium 



rhizogcncs does not utilize asparagin as a 

 sole source of carbon and nitrogen. 



Source: Isolated by Banfield {loc. cit.) 

 and by Hildebrand {loc. cit.) from rasp- 

 berry canes, Rubus spp. 



Habitat : Pathogenic on black and 

 purple cane raspberries, and blackberries, 

 and to a lesser extent on red raspberries. 



4. Agrobacterium radiobacter (Bei- 

 jerinck and van Delden) Conn. {Bacillus 

 radiobacter Beijerinck and van Delden, 

 Cent. f. Bakt., II Abt., 9, 1902, 3; Bac- 

 terium radiobacter Lohnis, Cent, f . Bakt., 

 II Abt., 14, 1905, 589; Rhizobium radio- 

 bacter Pribram, Klassifikation der Schizo- 

 myceten, Leipzig, 1933 ,5Z lAchromobacter 

 radiobacter Bergey ct al., Manual, 4th ed., 

 1934, 230; Alcaligenes radiobacter Conn, 

 in Manual, 5th ed., 1939, 97; Conn, Jour. 

 Bact., U, 1942,359.) From Latin, mdn^s, 

 the spoke of a wheel; Latin, bactrum, 

 a rod. 



Small rods, 0.15 to 0.75 l^y 0.3 to 2.3 

 microns, occurring singly, in pairs and 

 under certain conditions, in star-shaped 

 clusters. Motile with one to four flagella. 

 Prevailingly Gram-negative ; but an occa- 

 sional culture is variable. 



Nutrient gelatin stab : No liquefaction. 



Agar slant: Flat, whitish slimy layer. 



Mannitol-calcium-glycerophosphate- 

 agar streak plates: Abundant, raised, 

 slimy growth surrounded by a brown 

 halo with an outer zone of white precip- 

 itate (Riker et al.. Jour. Agr. Res., 41, 

 1930, 524). 



Broth: Turbid; with heavy ring or 

 pellicle if veal infusion is present. 



Litmus milk : Serum zone with pellicle 

 in one week; usually turns a chocolate 

 brown in 2 weeks; same in plain milk, 

 but with less browning. 



Potato : Raised slimy mass becoming 

 brownish; potato may be browned. 



Nitrates disappear (assimilated or 

 reduced). 



Starch not hydrolyzed. 



No organic acid or visible gas from 

 sugars; nearly all sugars, glycerol and 



