First report of Dickeya dianthicola and Pectobacterium wasabiae causing aerial stem rot of potato in Michigan, USA

Abstract

Figure 1Figure 2 Pectolytic Dickeya spp. and Pectobacterium spp. are commercially important seed-borne bacteria of potato (Solanum tuberosum) that cause blackleg, soft rot and aerial stem rot (Potrykus et al., 2014;Stevenson et al., 2001). Dickeya and Pectobacterium spp. have been recovered from potato production fields in parts of the USA (Dickey, 1979;Ma et al., 2007) Five seven-week-old cv. 'Russet Norkotah' potato plants were woundinoculated by inserting a sterile 18-gauge needle just above a central leaf axil at a depth of 1 mm. A 100 μl drop of inoculum (10 6 cfu/ml) was placed on the wound. Plants were exposed to a 24 h leaf wetness period (90 to 100% relative humidity in a mist chamber) until symptom expression (Figs. 1, 2), and lesions were measured. All three inoculated plants exhibited blackening of the stem and in advanced stages, drying and cracking (Figs. 1, 2). Upon desiccation, the lesions became shriveled and turned dark brown to black. Water-inoculated controls were nonsymptomatic (Figs. 1, 2). The reisolated bacteria caused pitting on crystal violet pectate agar (Hélias et al., 2012) and exhibited the same morphology as original cultures on NBY, and were confirmed as D. dianthicola using 16S rRNA and acnA coding sequences, and P. wasabiae using rRNA, acnA and mdh coding sequences, fulfilling Koch's postulates. To our knowledge, this is the first report of D. dianthicola and P. wasabiae causing aerial stem rot of potato in Michigan. References

Species of Dickeya and Pectobacterium Isolated during an Outbreak of Blackleg and Soft Rot of Potato in Northeastern and North Central United States

“…The number of strains varied by state: Florida (1), Hawaii (5), Maine (11), Massachusetts (1), Michigan (2), Minnesota (50), New Jersey (1), New York (20), North Dakota (25), and Pennsylvania (5) ( Table 1 ). Isolation and initial classification and identification of bacteria were conducted as previously described [ 13 , 15 , 22 , 38 ]. A total of 26 type strains were included in the study ( Table 2 ).…”

“…Dickeya solani has not been isolated from any of the samples collected in 2015–2016. Pectobacterium parmentieri [ 19 ] emerged from the surveys as another pectolytic soft rot pathogen associated with recent aerial soft rot outbreaks in Maine, New York, Minnesota, North Dakota, and Michigan [ 15 , 19 , 20 , 21 , 22 ]. Although the species P. parmentieri was only recently described, it has been in Wisconsin since at least 2001 and is also present in Hawaii [ 19 , 23 , 24 , 25 ].…”

Complete Genome Sequence of Dickeya dianthicola ME23, a Pathogen Causing Blackleg and Soft Rot Diseases of Potato

“…Historically, most blackleg disease in the United States was caused by bacteria now classified as Pectobacterium species. A new devastating form of blackleg caused by bacteria of the genus Dickeya emerged in 2014 and has been confirmed in most potato production states and two provinces in Canada (1–6). Multiple Dickeya species are capable of causing this disease (7), but Dickeya dianthicola appears to be the only species presently causing significant losses in North America (1).…”

The Identification of Cucumber Soft Rot and Wilting in Ukraine Based on 16S rRNA Gene Sequencing Analysis

“…Але, незважаючи на зазначене вище, таксономічний статус даного збудника до сих пір є невизначеним. Відомо, що за сучасними даними літератури симптоми гниття та в'янення ряду овочевих культур викликають окремі види фітопатогенних бактерій родів Erwinia, Pectobacterium, Dickeya [3, 5,6]. Завдяки широкому використанню філогенетичного аналізу у таксономії бактерій систематика даних родів зазнала значних змін.…”