Which Bacterium Contains a Large Ti Plasmid and Causes Crown

Question

Which bacterium contains a large Ti plasmid and causes crown gall disease in plants?
A) Agrobacterium rhizogenes
B) Agrobacterium tumefaciens
C) Aliivibrio fischeri
D) Butyrivibrio fibrisolvens

Accepted Answer

Agrobacterium tumefaciens is known to contain a large Ti (tumor-inducing) plasmid that transfers a portion of the plasmid DNA into plant cells, leading to the formation of crown gall tumors on plants. A. rhizogenes also causes root tumors but does not contain a Ti plasmid. A. fischeri is a bioluminescent bacterium that forms a symbiotic relationship with certain squid species. B. fibrisolvens is a Gram-positive bacterium that is found in the rumen of cows and is important for digestion.