Evidence that nematodes may vector the soft rot‐causing enterobacterial phytopathogens

Abstract

Bacterial soft rot is a globally significant plant disease that causes major losses in the production of many popular crops, such as potato. Little is known about the dispersal and ecology of soft-rot enterobacteria, and few animals have been identified as vectors for these pathogens. This study investigates whether soil-living and bacterial-feeding nematodes could act as vectors for the dispersal of soft-rot enterobacteria to plants. Soft-rot enterobacteria associated with nematodes were quantified and visualized through bacterial enumeration, GFP-tagging, and confocal and electron scanning microscopy. Soft-rot enterobacteria were able to withstand nematode grazing, colonize the gut of Caenorhabditis elegans and subsequently disperse to plant material while remaining virulent. Two nematode species were also isolated from a rotten potato sample obtained from a potato storage facility in Finland. Furthermore, one of these isolates (Pristionchus sp. FIN-1) was shown to be able to disperse soft-rot enterobacteria to plant material. The interaction of nematodes and soft-rot enterobacteria seems to be more mutualistic rather than pathogenic, but more research is needed to explain how soft-rot enterobacteria remain viable inside nematodes.

Acrobeloides buetschlii as a potential vector for enteric pathogens

“…The mCherry-labelled Salmonella were seen only internally within the gut of the nematodes, and none was observed on the nematode cuticle. Many bacterial and fungal pathogens interact with nematodes by initially binding to the cuticle (Hodgkin et al, 2000;Nussbaumer et al, 2004;Lee et al, 2011), yet, similar to our finding, no attachment to the cuticle was observed in the case of E. coli and C. elegans (Nykyri et al, 2014). Enteropathogenic bacteria, such as Salmonella, express a wide array of fimbriae and other proteinaceous adhesins that mediate bacterial adherence to host cells and to a range of abiotic surfaces (Jaglic et al, 2014).…”

A review on Dickeya solani , a new pathogenic bacterium causing loss in potato yield in Europe

“…The SRE are found worldwide and have been isolated from plants of more than half of angiosperm families as well as from soil, rivers, ground waters, insects, molluscs, and nematodes (Perombelon and Kelman, 1980;Perombelon, 2002;Ma et al, 2007;Laurila et al, 2008;Nykyri et al, 2014;Parkinson et al, 2014). They are Gram-stainnegative, rod-shaped, facultative anaerobes that produce a wide range of PCWDE and cause diseases such as blackleg and soft rot.…”

Bacterial Diseases of Crops

“…The evidence that soft rot enterobacteria such as Pectobacterium carotovorum colonize nematodes and use them as vectors suggests the importance of nematodeeplant pathogen interaction in plant disease epidemiology (Nykyri et al, 2013). Under field conditions, the bacterial-feeding nematodes may transport bacteria to a relatively short distance, such as between neighboring potato tubers or plants or from unrotten plant remnants to healthy plants in arable land.…”