Plant Pathology (2011) 60, 762-775

N. Vovlas, A. Troccoli, J.E. Palomares-Rius, F. De Luca, G. Liébanas, B.B. Landa, S.A. Subbotin and P. Castillo (2011)
Ditylenchus gigas n. sp. parasitizing broad bean: a new stem nematode singled out from the Ditylenchus dipsaci species complex using a polyphasic approach with molecular phylogeny
Plant Pathology 60 (4), 762-775
Abstract: Morphologial, biochemical, molecular and karyological analyses of different populations and races of the stem and bulb nematode Ditylenchus dipsaci have suggested that it represents a species complex, of which only D. dipsaci sensu stricto and its morphologically larger variant, known as the giant race of the stem and bulb nematode, are plant parasites of economic importance. The present study singles out the giant race from this complex, herein described as a new species named Ditylenchus gigas n. sp., on the basis of morphological and molecular data obtained from several populations collected from broad beans in southern Italy, southern Spain and Lebanon. The new species epithet, which refers to the large body size of the nematode with respect to the normal races, must be considered to be conspecific with the D. dipsaci 'giant race' from Fabaceae in recent literature. Morphologically, the new species is characterized by a body size 1·5-2 times longer than the 'normal race', stylet delicate (11·5-13·0 μm long) with knobs distinctly sloping backwards, and long post-vulval uterine sac (81-150 μm long). Results of molecular analysis of rDNA sequences including the ITS1-5.8S-ITS2 region, the D2-D3 fragment of the 28S gene, the small 18S subunit, the partial mitochondrial gene for cytochrome c oxidase I (mtCOI), and hsp90 gene sequences, support the new taxonomic species status for the former D. dipsaci giant race from Vicia faba, and clearly distinguish D. gigas n. sp. from D. dipsaci sensu stricto.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Pablo Castillo, Blanca B. Landa, Francesca De Luca, Nicola Vovlas, Juan E. Palomares-Rius, Alberto Troccoli

Research topic(s) for pests/diseases/weeds:
identification/taxonomy
molecular biology - genes

---

Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ditylenchus dipsaci
	Ditylenchus gigas	Broad/faba bean (Vicia faba)	Italy
	Ditylenchus gigas	Broad/faba bean (Vicia faba)	Lebanon
	Ditylenchus gigas	Broad/faba bean (Vicia faba)	Spain (Canary Is.)