Comparison of two sympatric Pasteuria populations isolated from a tropical vertisol soil

Abstract

An isolate of Pasteuria (designated PPMJ) recovered from the root-knot nematode Meloidogyne javanica, was characterized using host preference, spore morphometrics, and serology, and compared with another sympatric Pasteuria isolate (designated PPHC) collected from the cyst nematode, Heterodera cajani. PPMJ spores were larger (x 1.5) than the PPHC spores and had a mean diameter of 3.4 μm after fixation for electron microscopy. The central body of PPMJ spores was about twice as big as the central body of PPHC spores. The host preference tests, based on spore attachment to the nematode cuticle, revealed that Meloidogyne incognita, M. javanica, M. hapla, Pratylenchus coffeae, and Pratylenchus sp. were hosts of PPMJ but not of PPHC. It was found that males of Radopholus similis were hosts of PPHC. Western blot analysis of spore extracts probed with a polyclonal antiserum raised against PPHC spores showed an antigenic ladder which had similarities to lipopolysaccharide; another antiserum revealed differences in the molecular weight of antigens of the different spore isolates. Population diversity can therefore be vastly altered by the maintenance and culture of the bacterium on a particular host. The implications of these results are discussed in relation to the use of Pasteuria as a biological control agent.

Genotyping of single spore isolates of aPasteuria penetranspopulation occurring in Florida using SNP-based markers

“…However, in the case of M. javanica , 16SSP and 30SSP had the highest attachment rates, while the other SSP lines had significantly lower attachment rates not different from each other. The local adaptation of a parasite to its sympatric host population has been observed in a wide range of parasite populations (Sharma and Davies ). The preference of P. penetrans SSP lines for their local host population is of practical interest when they are used to control local nematode populations.…”

The Cyst Nematodes

“…It raises a number of questions with respect to inter and intra specific variation on behalf of both the nematode and the parasite. Western blot analysis of protein profiles extracted from the surface of the obligate bacterial hyperparasite, Pasteuria, readily revealed differences between antigens of different bacterial isolates (Sharma and Davies, 1996b); presumably these surface antigens are important in bacterial virulence, as will be shown below, and the observed antigenic polymorphism is a product of the co-evolutionary interaction between nematode host and parasite as suggested by Haldane (1949). As far as a nematode is concemed, its plant host is just one part of its ecological niche and viewed from the perspective of a tritrophic interaction similar highly specific coevolutionary interactions would undoubtedly develop between nematodes and their hyperparasites.…”

Parallel Microbial Ecology of Pasteuria and Nematode Species in Scottish Soils

“…and Pratylenchus spp. has been reported (Oostendorp et al, 1990;Sharma and Davies, 1996). De Gives et al (1999) tested the attachment of five Pasteuria endospore isolates to a range of nematodes finding that, while the attachment profile of two isolates from M. incognita were fastidious within RKN, isolates from three Heterodera spp.…”