162 



MANUAL OF DETERMINATI\'E BACTERIOLOGY 



Milk: Slightly acid. No coagulation. 

 Peptonization. 



Nitrites not produced from nitrates. 



Acid but not gas from lactose. 



Starch hydrolyzed. 



Optimum temperature 29° to 30 °C. 

 Maximum 39°C. Minimum 2.5°C. 



Aerobic. 



Source : Isolated from leaf -spot of 

 castor-bean. 



Habitat : Pathogenic on Ricinus com- 

 munis. 



23a. Xanthomonas transtucens f. sp. 

 hordei Hagborg. (Canadian Jour, of 

 Res., W, 1942, 317.) From L. trans- 

 lucens, shining through, translucent, 

 referring to the character of the lesion 

 produced by this pathogen. Form name 

 from Hordeum, a generic name. 



Synonyms : Bacterium iranslucens 

 Jones, Johnson and Reddy, Jour. Agr. 

 Res., 11, 1917, 637; Pseudomonas irans- 

 lucens, ibid. ; Phytomonas iranslucens 

 Bergey et al. Manual, 3rd ed., 1930, 252; 

 Xanthomonas iranslucens Dowson, Cent, 

 f. Bakt., II Abt., 100, 1939, 190. 



Rods: 0.5 to 0.8 by 1 to 2.5 microns. 

 Motile with a single polar flagellum. 

 Gram-negative. 



Gelatin: Liquefaction. 



Beef-peptone agar colonies : Round, 

 smooth, shining, amorphous except for 

 inconspicuous somewhat irregular con- 

 centric striations within, wax-yellow 

 tinged with old gold; margin entire. 



Broth : Turbidity becomes rather 

 strong. Pellicle. 



Milk: Soft coagulum and digestion. 

 Milk clears. Tyrosine crystals produced. 



Nitrites not produced from nitrates. 



Indole: Slight formation. 



Hydrogen sulfide produced. 



Lipolytic (Starr and Burkholder, Phy- 

 topath., 32, 1942,600). 



Ammonia from peptone. 



Acid but not gas from glucose, d- 

 fructose, d-mannose, d-galactose, sucrose, 

 lactose, and sometimes salicin. No uti- 

 lization of 1-rhamnose, inositol, maltose, 



raffinose, inulin, d-mannitol, and dul- 

 citol. 



Starch hydrolyzed. 



Optimum temperature 26 °C. Maxi- 

 mum 36 °C. Minimum 6°C. 



Aerobic. 



Distinctive characters : All forms of 

 Xanthomonas iranslucens have the same 

 cultural characters. They differ mainly 

 in pathogenicity. This form is patho- 

 genic on barley, Hordeum spp. ; but not 

 on oats, Avena spp., rye, Secale cereale 

 nor on wheat, Triiicum spp. 



Source : Isolated from leaves and seed 

 of barley, Hordeum vulgare. 



Habitat : Occurs naturally on barley. 



23b. Xanthomonas iranslucens f. sp. 

 undulosa (Smith, Jones and Reddy) Hag- 

 borg. {Bacterium iranslucens var. undu- 

 losum Smith, Jones and Reddy, Science, 

 50, 1919, 48; Pseudomonas iranslucens 

 var. undulosa Stapp, in Sorauer, Handb. 

 d. Pflanzenk., 2, 5 Auf., 1928, 17; Phyto- 

 monas iranslucens var. undulosa Hagborg, 

 Canadian Jour. Res., H, 1936, 347; Hag- 

 borg, Canadian Jour. Res., 20, 1942, 317.) 

 From L. unda; M.L. undulosus , undulate, 

 referring to the undulation of the colony. 



Distinctive characters : Cultural char- 

 acters same as all forms of Xanthomonas 

 iranslucens. Pathogenic on wheat, Tri- 

 ticium spp., barley, Hordeum spp. and 

 rye, Secale cereale but not on oats, 

 Avena spp. 



Source : Isolated repeatedly from black 

 chaff of wheat. 



Habitat : Usually found on wheat caus- 

 ing the black chaff, and on rye. 



23c. Xanthomonas iranslucens f. sp. 

 secalis (Reddy, Godkin and Johnson) 

 Hagborg. {Bacterium iranslucens var. 

 secalis Reddy, Godkin and .lohnson. 

 Jour. Agr. Res., 28, 1924, 1039; Psew- 

 domona iranslucens var. secalis Stapp, 

 in Sorauer, Handb. d. Pflanzenkr., 2, 5 

 Aufl., 1928,24; Phytomonas iranslucens 

 var. secalis Burkholder, in Manual, 5th 

 ed., 1939, 160;Hagborg, Canadian Jour. 



