Sero-groups ofErwinia carotovoraassociated with water, soil, tuber, and stems of potato plants in Western Australia

Abstract

Soft-rot erwinias were isolated from irrigation water, soil, tubers, and stems from spring (1986) and summer (1987) crops of potato at a field in Manjimup, Western Australia. Most of the isolates from all environments in both seasons belonged to Erwinia carotovora pv. carotovora (Ecc), with the exception of those from stems of the summer crop which were predominantly (68%) Erwinia carotovora pv. atroseptica (Eca) and belonged to sero-group SGI. In spring, SGm was recorded from all environments tested, while SGI was found only in stems and tubers. SGVI was recorded from stems (8%) and soil (15%) only in summer and in water (6.4%) only in spring. In spring, SGV, which was the predominant (28.2%) sero-group isolated from stems, was also found in water, soil, and tubers. In summer, of the SGs isolated from stems, SGm occurred in soil and tubers and SGVI in soil. Although SGXXIX was the most common in water in both seasons, it was isolated from stems only in summer. In a pathogenicity test, representative isolates of all serogroups isolated from stems, caused lesions on stems. Significant proportions of isolates from all environment in both seasons belonged to none of the known sero-groups.

Pectobacterium and Dickeya: Environment to Disease Development

“…carotovora or Erwinia chrysanthemi, indicating that isolates belonged simply to the present Pectobacterium or Dickeya genera. Serological analysis performed in these early works identified up to 21 serogroups, and a significant proportion of the isolates did not belong to known serogroups, pointing out the wide diversity of these isolates (Cappaert et al 1988;Peltzer and Sivasithamparam 1988;Powelson and Apple 1984). Unfortunately, most of the strains isolated in nonhost environments in these studies were not deposited in international collections.…”

“…However, the frequency of detection tended to increase in rivers close to arable land, suggesting that irrigation water can serve as a potential source of inoculum for SRP species. Numerous reports have pointed to the contamination of surface water by SRP (Cappaert et al 1988;Gudmestad and Secor 1983;McCarter-Zorner et al 1984;Peltzer and Sivasithamparam 1988) and the potential contamination of plants via water reservoirs (Franc and Harrison 1987). The presence of Pectobacterium spp.…”

“…In addition, direct methods such as DNA-based amplification and ELISA will detect dead bacterial cells resulting in an overestimation of the risks for infection. To improve the diagnostic sensitivity of assays, incubation of soil samples in a broth under low oxygen conditions can be done, which allows multiplication of SRP and enhances the probability of detecting and isolating the target bacteria (Peltzer and Sivasithamparam 1988;Powelson and Apple 1984). The efficiency of cultivation-based techniques, however, can be affected by the high microbial background in the soil that interferes with the growth of SRP.…”

“…In Australia in spring, 25 % of all soil samples taken from fields the year before potatoes were planted, were contaminated with SRP including 93 % P. carotovorum, 5.6 % P. atrosepticum, and 1.9 % Dickeya spp. (Peltzer and Sivasithamparam 1988).…”

Diseases Caused by Pectobacterium and Dickeya Species Around the World

“…In 2017, the production was 1.1 megatonnes from 28,000 hectares (www.potatopro.com/nl). P. carotovorum and P. atrosepticum have been found in association with potato tubers (Peltzer and Sivasithamparam 1988). The pathogens were isolated from the potato ecosystem, including water and soil (Peltzer and Sivasithamparam 1988).…”