FAMILY II. RHIZOBIACEAE 



291 



sine, 1-cystine, d-glutamic acid and yeast 

 extract can be used as a source of nitrogen 

 (Pinckard, loc. cit.). 



Temperature relations: Optimum, 28° C. 

 Minimum, 8° C. Maximum, 36° C. (Pinck- 

 ard, loc. cit.). 



Distinctive characters: Differs from Agro- 

 bacterium 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 (Phyto- 

 path., 33, 1943, 317) state that this species, 

 unlike Agrobacterium tumefaciens and Agro- 

 bacterium rhizogenes, does not utilize as- 

 paragin as a sole source of carbon and nitro- 

 gen. 



Source: Isolated from raspberry canes, 

 Rubus spp. 



Habitat: Pathogenic on black and purple 

 cane raspberries, on blackberries and, to a 

 lesser extent, on red raspberries. 



6. Agrobacleriuni radiobacter (Bei- 



jerinck and van Delden, 1902) Conn, 1942. 

 {Bacillus radiobacter Beijerinck and van 

 Delden, Cent. f. Bakt., II Abt., 9, 1902, 3; 

 Conn. Jour. Bact., 44, 1942, 359.) 



ra.di.o.bac'ter. L. noun radius a ray, 

 beam; M.L. bacter masculine equivalent of 

 Gr. neut.n. bactrum a rod or staff; M.L. 

 mas.n. radiobacter ray rod. 



Small rods, 0.15 to 0.75 by 0.3 to 2.3 mi- 

 crons, occurring singly, in pairs and, under 

 certain conditions, in star-shaped clusters. 

 Motile with one to four flagella. Prevail- 

 ingly Gram-negative, but an occasional 

 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 w'ith 

 an outer zone of white precipitate (Riker 

 et al.. Jour. Agr. Res., 41, 1930, 524). 



Broth: Turbid; 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. 



Starch not hydrolj'zed. 



No organic acid or visible gas from sugars ; 

 nearly all sugars, glycerol and mannitol 

 are utilized with the production of CO 2. 



Nitrates completely assimilated; test for 

 nitrites may be negative (Hofer, Jour. Bact., 

 41, 1941, 202). 



Temperature relations: Optimum, 28° C. 

 Minimum, near 1° C. Maximum, 45° C. 



Aerobic. 



Media containing KNO3, K2HPO4 and 

 glycerol, ethanol or propanol become alka- 

 line to phenol red (Sagen, Riker and Bald- 

 win, Jour. Bact., 28, 1934, 581). 



Growth occurs in special alkaline media 

 of pH 11.0 to 12.0 (Hofer, Jour. Amer. Soc. 

 Agron., 27, 1935, 228). 



Hydrogen sulfide produced if grown in 

 ZoBell and Feltham's medium (ZoBell and 

 Feltham, Jour. Bact., 28, 1934, 169). 



Distinctive characters: Browning of man- 

 nitol-calcium-glycerophosphate agar; in- 

 ability to cause plant disease or to produce 

 nodules on roots of legumes; complete uti- 

 lization of nitrate (the nitrate disappears) 

 in the peptone-salt medium of Riker et al. 

 (Riker et al., Jour. Agr. Res., 4I, 1930, 529) 

 and failure to absorb congo red (Riker et 

 al., ibid., 528). 



This species bears at least superficial 

 resemblances to certain Rhizobium spp. 

 but may be distinguished from them by 

 the first two characters listed above and 

 by the following in addition: Growth at a 

 reaction of pH 11 to 12; heavy ring or pel- 

 licle formation on veal infusion broth; hy- 

 drogen sulfide production in the mannitol - 

 tryptone medium of ZoBell and Feltham 

 (ZoBell and Feltham, op. cit., 1934, 169); 

 production of milky white precipitate on 

 nitrate-glycerol-soil-extract agar. 



Source: Isolated from soil. 



Habitat: Soil around the roots of plants, 

 especially legumes. 



7. Agrobacterium stellulatum Stapp 

 and Knosel, 1954. (Zent. f. Bakt., II Abt., 

 108, 1954, 244.) 



stel.lu.la'tum. L. noun stella star; M.L. 

 adj. stellulatus resembling a small star. 



Rods, 0.2 to 0.8 by 0.3 to 2.1 microns, oc- 

 curring singly or in pairs; in certain media, 

 star-like clusters are found. Motile by means 



