Author
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ATIBALENTJA, NDEME - U OF ILL, URBANA |
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Noel, Gregory |
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Submitted to: Nematropica
Publication Type: Abstract Only Publication Acceptance Date: 4/16/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: The life cycle and ultrastructure of a Pasteuria isolate that parasitizes Heterodera glycines in Illinois was investigated with light and transmission electron microscopy of juveniles, adults, and cysts extracted from soybean roots and rhizosphere. To determine the phylogeny of the Illinois Pasteuria, a 1.5-kb region of the 16S rDNA obtained from endospores was PCR-amplified, sequenced, and compared to homologous sequences of 32 other bacterial species, including the Daphnia endosymbiont, P. ramosa, and P. penetrans, parasite of Meloidogyne spp. Endospores that adhered to the cuticle of second-stage juveniles (J2) of H. glycines did not germinate until the J2 invaded the roots. Then, germ tubes differentiated from the endospores and penetrated into the body of J2. The life cycle is completed only in females. Ultrastructure revealed similarities and differences between the Illinois isolate of Pasteuria and P. nishizawae, the only other Pasteuria known to attack H. glycines. Mature endospores were similar, but those of the Pasteuria from Illinois were larger. Also, the laminated mesosome-like bodies observed in earlier stages of the endosporogenesis of the Illinois isolate differed in nature and function from the vesicular mesosomes involved in the forespore septum formation in P. nishizawae. Phylogenetic analyses placed the Pasteuria at the base of a clade that contained Alicyclobacillus spp., and further showed that P. ramosa diverged before the speciation of nematode-infecting Pasteuria. |
