Detection and characterization of Pasteuria 16S rRNA gene sequences from nematodes and soils

Abstract

Various bacterial species in the genus Pasteuria have great potential as biocontrol agents against plant-parasitic nematodes, although study of this important genus is hampered by the current inability to cultivate Pasteuria species outside their host. To aid in the study of this genus, an extensive 16S rRNA gene sequence phylogeny was constructed and this information was used to develop cultivation-independent methods for detection of Pasteuria in soils and nematodes. Thirty new clones of Pasteuria 16S rRNA genes were obtained directly from nematodes and soil samples. These were sequenced and used to construct an extensive phylogeny of this genus. These sequences were divided into two deeply branching clades within the low-G+C, Gram-positive division; some sequences appear to represent novel species within the genus Pasteuria. In addition, a surprising degree of 16S rRNA gene sequence diversity was observed within what had previously been designated a single strain of Pasteuria penetrans (P-20). PCR primers specific to Pasteuria 16S rRNA for detection of Pasteuria in soils were also designed and evaluated. Detection limits for soil DNA were 100-10 000 Pasteuria endospores (g soil) 21 .

Pasteuria penetrans and Its Parasitic Interaction with Plant Parasitic Nematodes

“…A similar analysis applied to P. penetrans (Atibalentja et al 2000) proved, predictably, its relatedness to the cladoceran parasite, and also their positioning within the genus Bacillus. Using a number of different isolates of Pasteuria spp., Duan et al (2003) confirmed the positioning within the low G+C Gram-positive genera and, in particular, with the family "Alicyclobacillaceae". Fortunately, the differences in host range and morphometrics that had resulted in the designation of two other presumptive species, P. thornei and P. nishizawae were borne out in this analysis by genetic differences large enough to be significant.…”

“…from infected nematodes and the soil by Duan et al (2003) allowed the design of Pasteuria-specific PCR primers. The resulting amplification fragments shared highly conserved restriction enzyme sites not found in any of the non-Pasteuria sequences that were interrogated in silico.…”

Identification of New Single Nucleotide Polymorphism-Based Markers for Inter- and Intraspecies Discrimination of Obligate Bacterial Parasites (Pasteuria spp.) of Invertebrates

“…from around the globe, but there is very little understanding of the genetic variation between and within populations. Previous studies have focused on the position of P. penetrans in the bacterial kingdom (9,31,34) and the use of consensus 16S rRNA gene sequences (6,7,18) to differentiate between species and populations of Pasteuria (5,16,33). However, this information has not been extensively supported with sequence data from protein-encoding genes, which potentially provide an additional source of discrimination, with the exception of one study examining partial coding sequences of some genes in P. ramosa populations (32), as well as a recent study of genes encoding collagen-like proteins in this species (22a).…”

Vertical Distribution of Pasteuria penetrans Parasitizing Meloidogyne incognita on Pittosporum tobira in Florida

“…The Pasteuria sp. was identified as P. penetrans based on the 16S ribosomal profile (Duan et al, 2003;Waterman et al, 2006). It was logical to expect nematode suppression in this 10-yrmonoculture field, but the nematodes were present at damaging levels making the field unproductive.…”