Answers are grounded in this paper and cite their sources.
SUMMARY: The vitamin requirements of 63 strains of Rhizobium and 18 of Agrobacterium were examined. R. trifolii, R. leguminosarum and R. phaseoli responded in most cases to thiamine, biotin, and calcium pantothenate. Strains of R. meliloti and the slow-growing rhizobia sometimes responded to biotin, but not to the other vitamins. An unknown growth factor, active for the slow-growing rhizobia, was detected. Three strains of Agrobacterium required thiamine.
No takes yet. Share an insight, caveat, or question.
P. H. Graham (1963) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: