The physiology of bacterial tumors in plants and of habituation

Abstract

In February, 1904, the Bureau of Plant Industry, U. S. Department of Agriculture, received a shipment of paris daisy plants (Chrysanthemum frutescens L.) from a New Jersey grower. All of the plants had gall-like growths on the stems, the older plants being more severely affected than were the younger plants. The plants were turned over to Dr. Erwin F. Smith, Chief Pathologist of the Bureau, for diagnosis of the disease and for suggestions on control measures. Smith first considered the possibility that the galls resulted from a fungus infection, but none was detected by appropriate procedures. Mechanical injuries, insect bites, etc., were also ruled out as the cause of the tumors. After some months of fruitless work, bacteria were detected in freshly-cut sections of undecayed galls, and early in 1906 a pathogenic organism was isolated as a pure culture. On June 1, 1906, isolates of these bacteria were inoculated into healthy plants, and on June 18th tumor formation was macroscopically evident. Robert Koch’s postulates were fulfilled by December and in April, 1907, the causal organism, Bacterium tumefaciens Sm. and Town, (now Agrobacterium tumefaciens Sm. and Town [Conn.] Bergey et al.) was formally described in the journal “Science” (Smith and Townsend 1907).

The survey of literature pertaining to this review was concluded in May, 1960.