Identification of a bacterium isolated from galls on carrot and weeds

Abstract

In 2004, bacterial galls were found on the roots of carrots in Shizuoka Prefecture, Japan. Galls were about 0.1-2 cm in diameter, light brown in color and had rough surfaces. In 2005, similar galls were found on the roots of three weeds: henbit (Lamium amplexicaule L.), Persian speedwell (Veronica persica Poir.) and leaf mustard (Brassica juncea L.). A bacterium that forms white, rough colonies was isolated from the carrot and weeds galls. The bacterial isolates had properties identical with Rhizobacter dauci Goto and Kuwata. Phylogenetic analysis based on 16S rDNA sequences showed that the carrot isolate had the highest homology (similarity of 100%) with that of the type strain of R. dauci. Rep-PCR genomic fingerprinting using BOX A1R primer showed that the carrot and weeds isolates were nearly identical. Pathogenicity of the isolates was confirmed by inoculating the roots of carrots and the weeds. After 2-5 weeks, they formed galls on the roots of the original host species and on other plant species tested. The galls were indistinguishable from those formed naturally, and the inoculated bacterium was reisolated. Thus, the causal bacterium of carrot and weeds gall was identified as R. dauci, and the bacterium was found to have a wider host range than previously known. These weed hosts may serve as inoculum sources for carrot bacterial gall disease.

Plant tumors: a hundred years of study

“…Rhizobacter dauci is a gram-negative bacterium that causes bacterial gall disease in carrot (Goto and Kuwata 1988) and that can also induce the formation of similar galls on the roots of henbit (Lamium amplexicaule), Persian speedwell (Veronica persica), and leaf mustard (Brassica juncea; Kawarazaki et al 2009). Small tumors induced by R. dauci develop massively along the entire length of the main and adventitious roots, as well as on the shoots.…”

Knots Untie: Molecular Determinants Involved in Knot Formation Induced by Pseudomonas savastanoi in Woody Hosts

“…Infected plants develop galls along the entire length of the storage roots from the crown to the root tip ( Goto and Kuwata, 1988 ). R. dauci appears to have an extremely wide host range and produces galls on the roots, stems and tubers of at least 46 plant species from 24 families, including relevant vegetables such as tomato and cabbage as well as many common weeds ( Kawarazaki et al, 2009 , 2012 ).…”

Bacterial brown stripe of rice in soil-less culture system caused by Acidovorax avenae subsp. avenae in China

“…avenae with 0.58-0.71 similarity indices. Also carbon source assimilation of the reference strain and the representative isolates was examined by the Biolog GN test kit (Biolog Inc., Hayward, CA, USA) according to the manufacturer's specifications and the protocol of Kawarazaki et al (2009). When the profile was compared with the BIOLOG identification database GN4.01, the reference strain and the isolates were identified as A. avenae subsp.…”