Meloidogyne chitwoodi
Golden et al.,1980
Introduction
M. chitwoodi is a major economic pest on potato in the Pacific
Northwest of North America and has become established in The Netherlands.
It is well adapted to cool soil temperatures where it can develop at 6
*C. Several races based on host range and isozymes have been reported.
It reproduces by facultative meiotic parthenogenesis.
Classification
Isozyme phenotypes, mitochondrial DNA and ribosomal DNA analysis all
indicate M. chitwoodi is quite genetically distinct from other Meloidogyne
species examined.
Morphological Identification:
The perineal pattern is round to oval, the female stylet (11-12.5 um)
is slightly curved dorsally with small, irregular knobs. The male has distinctive
large, lateral "lips" apparent in the light microscope. The juvenile tail
tip is characteristically broad and blunt (for Meloidogyne) with
a well-defined short hyaline area.
Molecular Identification:
Mitochondrial primer set C2F3/1108: This primer set amplifies
a 500 kb fragment in M.chitwoodi which when digested with Dra
I produces fragments of 290, 130, and 100 bp (lanes 1& 2). Digestion
of the same product from M. hapla produces fragments of 290
and 230 bp (lanes 3-6).
ITS
primer set: Produces a 700 bp fragment. Hinf I and SspI
both differentiate M.chitwoodi from M. hapla, M.graminicola,
M. mayaguensis, and the three "major" species.
Isozyme patterns: An esterase pattern of S1 has been observed for most
populations, although a variant found in The Netherlands has been designated
as a new race.
