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ARS Home » Midwest Area » Urbana, Illinois » Soybean/maize Germplasm, Pathology, and Genetics Research » Research » Publications at this Location » Publication #150328
Title: LIFE CYCLE, ULTRASTRUCTURE, AND HOST SPECIFICITY OF THE NORTH AMERICAN ISOLATE OF PASTEURIA THAT PARTASITIZES THE SOYBEAN CYST NEMATODE, HETERODERA GLYCINES

Author
item ATIBALENTJA, NDEME - UNIV OF ILLINOIS
item JAKSTYS, BIRUTE - UNIV OF ILLINOIS
item Noel, Gregory

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2004
Publication Date: 1/6/2004
Citation: ATIBALENTJA, N., JAKSTYS, B.P., NOEL, G.R. 2004. Life cycle, ultrastructure, and host specificity of the North American isolate of pasteuria that partasitizes the soybean cyst nematode, heterodera glycines. Journal of Nematology.

Interpretive Summary: Soybean cyst nematode (SCN) is an important yield-limiting pest of soybean in all production areas of the US. Estimated annual crop loss ranges from $240 million to $1.4 billion. One area of research to control SCN that has received limited effort is biological control. The bacterium Pasteuria is an obligate parasite of nematodes, which means that it can only grow on the nematode host in soil. The species of Pasteuria that attacks SCN has been shown to cause significant reductions in nematode numbers. The life cycle was unknown until this research was done. This paper documents the life cycle with photographs, electron micrographs, and reports the host range of the Pastueria, which is limited to cyst nematodes closely related to SCN. Knowledge of the life cycle will provide data for future studies to discover genes that govern certain aspects of the life cycle. This will lead to the ability to culture the Pasteuria on artificial media. Once this is accomplished, Pasteuria can be grown in sufficient quantities to be used commercially to control SCN. These results will be of interest to all soybean nematologists and other scientists interested in managing SCN.

Technical Abstract: Light and transmission electron microscopy were used to investigate the life cycle and ultrastructure of an undescribed isolate of Pasteuria that parasitizes the soybean cyst nematode, Heterodera glycines. Studies also were conducted to determine the host specificity of Pasteuria. The endospores that attached to the cuticle of second-stage juveniles (J2) of H. glycines in soil did not germinate until the encumbered nematodes invaded soybean roots. Thereafter, the bacterium developed and completed its life cycle only in females. The stages of endosporogenesis were typical of Pasteuria spp. The mature endospore, like that of P. nishizawae, the only other Pasteuria known to infect H. glycines and which is native to Japan, produces an epicortical layer that completely surrounds the cortex, an outer spore coat that tapers progressively from the top to the base of the central body, and a double basal adhesion layer. However, subtle differences exist between the Pasteuria from North America and P. nishizawae with regard to the size of the central body, the nature and function of the mesosomes observed in the earlier stages of endosporogenesis, and the appearance of the fibers lining the basal adhesion layer and the exosporium of the mature endospore. Endospores of the North American Pasteuria attached to J2 of H. schachtii, H. trifolii, and H. lespedezae, but not to Meloidogyne arenaria race 1, Tylenchorhynchus nudus, or Labronema sp. Results from this study indicate that the North American Pasteuria is more similar to P. nishizawae than to any other known member of the genus. Additional evidence from comparative analysis of 16S rDNA sequences is needed to clarify whether these two Pasteuria belong to the same species.