|Van Den Berg, Esther|
Submitted to: Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2008
Publication Date: 7/9/2009
Publication URL: http://hdl.handle.net/10113/42566
Citation: Van Den Berg, E., Subbotin, S.A., Handoo, Z.A., Tiedt, L.R. 2009. Hirschmanniella kwazuna sp. n. from South Africa with notes on a new record of H. spinicaudata, Schuurmans Stekhoven,1944, Luc & Goodey, 1964 (Nematoda: Pratylenchidae) and on the molecular phylogeny of Hirschmanniella Luc & Goodey, 1964. Nematology. 11(4):523-540. Interpretive Summary: Nematodes are microscopic worms that feed on plant roots and cause global crop losses exceeding $100 billion annually. A major problem with determining the extent of crop loss due to nematodes is that the nematodes present in many areas are unknown. In this study, researchers from South Africa in collaboration with a scientist from California and an ARS scientist from Beltsville, Maryland describe and illustrate one new species and one known species of root nematodes from grasses in undisturbed grasslands from South Africa. Methods for identifying the new species were developed and were based on anatomical features obtained with light microscopes and high-powered electron microscopes, as well as DNA sequence data. The results are significant because they provide valuable details that allow this new species to be identified. This research will be of use to scientists, growers, action agencies and extension agencies involved in nematode research and control.
Technical Abstract: A new species of the genus Hirschmanniella, H. kwazuna sp. n., is described from grasses in undisturbed veld from South Africa. Hirschmanniella spinicaudata (Schuurmans Stekhoven, 1944) Luc & Goodey, 1964 is reported from South Africa for the first time. Hirschmanniella kwazuna sp. n. is characterized by having a very irregular heat-relaxed body posture, a 1522-2049 micrometers long body, a low rounded lip region with four to five lip annuli, a 18.0-22.5 micrometers long stylet, an areolated lateral field along whole length of body, a filled spermatheca, a tail with 62-81 ventral annuli narrowing to tip with a ventral mucro, angular crystal-like inclusions within body cavity in most of the specimens and a phasmid which is situated 12-24 annuli or 15-26 micrometers anterior to tail tip. Males similar to female including the crystal-like inclusions and tail curved strongly dorsad in most specimens. Juveniles are similar to females, with ventral tail projection more peg-like. Molecular sequence analysis using the D2-D3 expansion segments of 28S, partial 18S and ITS rRNA sequences allowed distinguishing Hirschmanniella kwazuna sp. n. from H. loofi and other species of the genus. Pylogenetic analyses based on analysis of the D2-D3, 18S and ITS rRNA genes are given for eight, ten and five valid and unidentified Hirschmanniella species, respectively.