Isolation and plant host range of Rhizobacter dauci, causal agent of carrot bacterial gall.

Abstract

(2012). Isolation and plant host range of Rhizobacter dauci, causal agent of carrot bacterial gall. Jpn. J. Phytopathol.78: 293-300.Bacterial galls were found on roots of tomato (Solanum lycopersicum), cabbage (Brassica oleracea), shepherd's purse (Capsella bursapastoris var. pinnata), bog yellowcress (Rorippa palustris), purple deadnettle (Lamium purpureum) and corn speedwell (Veronica arvensis) in Shizuoka Prefecture from December 2007 to July 2008. Galls had formed on the main or secondary roots, and bacterial aggregates were often observed on the surface of the galls. Bacterial isolates from the plant galls formed white, rough colonies and had properties identical to those of Rhizobacter dauci. Phylogenetic analysis based on 16S rDNA sequence showed that the isolates had the highest homology (similarity of 100%) with that of the type strain of R. dauci. Pathogenicity of the isolates was confirmed by inoculating the roots of carrots and the original host species. After 4 weeks, galls had formed on the roots of the plants, and the bacterium was reisolated. This report is the first of bacterial galls caused by R. dauci on tomato, cabbage, shepherd's purse, bog yellowcress, purple deadnettle and corn speedwell. To investigate the host range of R. dauci, 20 vegetable crop species of seven families were planted in a field infested with the bacterium. After 1.5 months, galls had formed on the roots of nine vegetables representing four families, and a bacterium that forms white, rough colonies was isolated from the infested plants. Pathogenicity of the isolates was confirmed by inoculating the roots of carrots; galls formed on the roots, and the bacterium was reisolated. After direct inoculation of 77 plant species from 24 families with the carrot isolate R. dauci O1, galls formed on the roots, stems or tubers of 46 plant species of 20 families, and the inoculated bacterium was reisolated. These results suggested that R. dauci has an extremely wide host range. It may commonly inhabit the roots of various plants in the field.

The Biology of Canadian Weeds. 159.Capsella bursa-pastoris(L.) Medik.

“…In California almond orchards, C. bursa-pastoris has been infected by the bacterium Xylella fastidiosa, a cause of almond leaf scorch, usually transmitted by hemipteran vectors such as the blue-green sharpshooter Graphocephala atropunctata Signoret (Shapland et al 2006). The bacterium Rhizobacter dauci, the causal agent of carrot bacterial gall, produced galls on the roots of a wide range of host species, including C. bursa-pastoris, in Japan (Kawarazaki et al 2012). Lee et al (2016) identified nine species of sporeforming bacilli bacteria from fresh samples of C. bursapastoris in South Korea: Bacillus drentensis, B. acidiceler, B. aryabhattai, B. asahii, B. firmus, B. pseudomycoides, B. psychrodurans, B. simplex, Bacillus sp., Paenibacillus lautus, P. barcinonensis, P. tundra, and Brevibacillus reuszeri.…”

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 ).…”