| Morphology | Agrobacterium |
| CELLULAR |
| Staining | Gram-negative. |
| Morphology | Rods, 0.6-1.0 um by 1.5-3.0 um, occurring singly or in pairs. |
| Motility | Motile by 1-6 peritrichous flagella. |
| Specialized structures | Nonsporing. |
| Division |
| COLONIAL |
| Solid surface | Colonies are usually convex, circular, smooth, nonpigmented to light beige. Growth on carbohydrate-containing media is usually accompanied by copious extracellular polysaccaride slime. |
| Liquid |
| Growth Parameters | Agrobacterium |
| PHYSIOLOGICAL |
| Tropism | Chemoorganotrophs, utilizing a wide range of carbohydrates, salts of organic acids and amino acids as carbon sources, but not cellulose, starch, agar or chitin. |
| Oxygen | Aerobic, possessing a respiratory type of metabolism with oxygen as the terminal electron acceptor. Some strains are capable of anaerobic respiration in the presence of nitrate. Most strains are able to grow under reduced oxygen tensions in plant tissues. |
| pH | |
| Temperature | Optimum temperature: 25-28`C |
| Requirements | Ammonium salts and nitrates can serve as nitrogen sources for strains of some species and biovars; others require amino acids and additional growth factors |
| Products | 3-Ketoglycosides are produced by the majority of strains belonging to A tumefaciens biovar l and A. radiobacter biovar l. Produce an acid reaction in minerals salts media containing D-glucose, D-galactose and other carbohydrates |
| Enzymes | Catalase-positive, and usually oxidase- and urease-positive |
| Unique features |
| ENVIRONMENTAL |
| Habitat | |
| Lifestyle | |
| Pathogenicity | With the exception of A.
radiobacter, members of this genus invade the crown,
roots and stems of a great variety of dicotyledonous and
some gymnospermous plants, via wounds, causing the
transformation of the plant cells into autonomously
proliferating tumor cells. The induced plant diseases are
commonly known as crown gall, hairy root and cane gall.
Some strains possess a wide host range, whereas others
(e.g. grapevine isolates) possess a very limited host
range. The tumors are self-proliferating and graftable.
Agrobacteria are soil inhabitants. Oncogenic strains
occur mainly in soils previously contaminated with
diseased plant material. Some non oncogenic Agrobacterium strains have been isolated from human clinical specimens. |
| Distribution |
| Genome | Agrobacterium |
| G+C Mol % | 57-63 (Tm) |
| The molecular weight of
the Agrobacterium genome ranges from 3.0 x 109-3.6 x 109.
The tumor induction by Agrobacterium is correlated with the presence of a large tumor-inducing plasmid (Ti-plasmid) in the bacterial cells. |
| Reference | Agrobacterium |
| First citation | Conn, H.J. 1942 Validity of the genus Alcaligenes J. Bacteriol 44:353-360 |
| The Prokaryotes | p |
| Bergey's Systematatic | p 244 K. Kersters and J. De Ley |
| Bergey's Determinative | p 74 |
| References |