Pseudomonas syringae pv. coriandricola, Incitant of Bacterial Umbel Blight and Seed Decay of Coriander (Coriandrum sativum L.) in Germany

Abstract

Since 1987 a devastating disease has occurred in coriander in Germany, characterized by dark‐brown discoloration of blossoms and umbels. water‐soaked and brown spots on leaves and stems, seed decay and willing. Infected tissue always contained large quantities of Gramnegative, rod‐shaped, motile bacteria with few polar flagella. Tests for LOPAT reactions showed the bacteria to be positive for levan‐production and tobacco hypersensitivity reaction but negative for oxidase reaction, rot of potato slices and arginine dihydrolase. The bacteria failed to produce fluorescent pigment on King's medium B but revealed a blue fluorescence after growing in a liquid medium without Fe, According to further standard nutritional, biochemical and physiological tests the coriander pathogen belongs to Pseudomonas group la. i.e. Pseudomonas syringae. Also, the fatty acid composition revealed a very close similarity to Pseuodomonas syringae. On Biolog plates the coriander strains showed a uniform metabolic pattern and could clearly be distinguished from other Pseudomonas syringae pathovars. Typical hosts of Pseudomonas syringae pv. syringae were not infected by the coriander pathogen. Also, most tested umbelliferae species reacted resistant towards the pathogen. Typical disease symptoms, such as persistent water‐soaked lesions, were incited only a Coriandrum saticum Animi majus and Levisticum offieinale. The studies revealed that the pathogen described is a separate pathovar of Pseudomonas syringae not included in the approved list of P. syringae pathovars. The name Pseudomonas syringae pv. coriandricola is proposed. Strain GSPB 1965 has been deposited in the NCPPB as pathotype strain (no. 3781).

Bacterial leaf spot of cilantro (Coriandrum sativum) in Ontario

“…Similar results to those of Toben and Rudolph (1996) were also observed for utilization of erythritol, DL-lactate, and quinate in isolates 3-8. However, the Ontario isolates did not hydrolyze Tween 80 but did grow on trigonelline, whereas Toben and Rudolph (1996) reported hydrolysis with all of their isolates and no growth on trigonelline. Furthermore, the Ontario isolates did not produce indole or form H 2 S in agreement with results of the nonfluorescent isolates of Taylor and Dudley (1980).…”

“…Similarly, there was also agreement with Toben and Rudolph (1996) in tests for pectolytic activity; nitrate reduction; gelatin liquefaction; ice nucleation activity; pectate degradation; and in utilization of Darabinose, benzoate, cellobiose, gluconic acid, glucose, homoserine, innositol, D-mannitol, L-rhamnose, sorbitol, sucrose, D(+)-trehalose dihydrate, and L-tartrate. Similar results to those of Toben and Rudolph (1996) were also observed for utilization of erythritol, DL-lactate, and quinate in isolates 3-8. However, the Ontario isolates did not hydrolyze Tween 80 but did grow on trigonelline, whereas Toben and Rudolph (1996) reported hydrolysis with all of their isolates and no growth on trigonelline.…”

“…Tests for LOPAT reactions (Lelliott et al 1966) were positive for levan production and tobacco hypersensitivity reaction but negative for oxidase and arginine dihydrolase in agreement with Toben and Rudolph (1996), Taylor andDudley (1980), Cooksey et al (1991), Pernezny et al (1997), andCazorla et al (2005). Similarly, there was also agreement with Toben and Rudolph (1996) in tests for pectolytic activity; nitrate reduction; gelatin liquefaction; ice nucleation activity; pectate degradation; and in utilization of Darabinose, benzoate, cellobiose, gluconic acid, glucose, homoserine, innositol, D-mannitol, L-rhamnose, sorbitol, sucrose, D(+)-trehalose dihydrate, and L-tartrate.…”

“…Nonfluorescence on KB was observed with the Ontario isolates and in P. syringae isolates from coriander reported by Cooksey et al (1991), , Pernezny et al (1997), Taylor and Dudley (1980), and Toben andRudolph (1996), whereas Nemeth et al (1969) described a fluorescent Pseudomonas species as the incitant of similar disease symptoms on coriander in Hungary. There was no reference to PHB accumulation in the first four reports, whereas Toben and Rudolph (1996) did not observe PHB accumulation in three of their strains. In contrast in this report, PHB accumulation occurred in all three isolates tested in the present study.…”

“…Collins & Sons Limited, Troy, Ont., personal communication, 2007). The disease has caused losses in coriander (cilantro) in Europe (Cazorla et al 2005;Mavridis et al 1990;Taylor and Dudley 1980;Toben and Rudolph 1996), Australia (Dennis and Wilson 1997; Refshauge and Nayudu 2001), and the United States (Cooksey et al 1991;Pernezny et al 1997). It has not been reported in the western Canadian provinces where production of coriander is extensive (Agriculture and AgriFood Canada 2007) and an Aureobasidium sp.…”