Morphological and molecular characterisation of Punctodera mulveyi n. sp. (Nematoda: Punctoderidae) from a golf course green in Oregon, USA, with a key to species of the Punctodera

Authors: KANTOR, MIHAIL - Oak Ridge Institute For Science And Education (ORISE); Handoo, Zafar; Skantar, Andrea; Hult, Maria; INGHAM, RUSS - Oregon State University; WADE, NADINE - Oregon State University; YE, WEIMIN - North Carolina Department Of Agriculture; Bauchan, Gary; Mowery, Joseph

Submitted to: Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2020
Publication Date: 11/17/2020
Citation: Kantor, M.A., Handoo, Z.A., Skantar, A.M., Hult, M.N., Ingham, R., Wade, N., Ye, W., Bauchan, G.R., Mowery, J.D. 2020. Morphological and molecular characterisation of Punctodera mulveyi n. sp. (Nematoda: Punctoderidae) from a golf course green in Oregon, USA, with a key to species of the Punctodera. Nematology. https://doi.org/10.1163/15685411-bja10068.
DOI: https://doi.org/10.1163/15685411-bja10068

Interpretive Summary: Plant-parasitic nematodes are microscopic worms that cause an estimated ten billion dollars of crop losses each year in the United States and 100 billion dollars globally. Cyst nematodes are the most economically important groups of plant-parasitic nematodes that damage the roots of many kinds of plants worldwide. One problem with cyst nematodes is that growers have no idea of how many kinds of nematodes exist. Some cyst nematodes infect turf grass (Poa annua) in golf course greens, which are important and are specifically developed to have fine texture and high plant density to provide a smooth playing surface for golfers to enjoy. In this study, a team of ARS scientists and colleagues from Oregon State University analyzed anatomical and molecular traits to identify the cyst nematode isolated from turf grass in Bandon, Coos County, Oregon. This is the first report of this new cyst nematode species from Oregon. This discovery is significant because new molecular and morphological information obtained for this new species will facilitate future identifications of this cyst nematode. This report will serve as a useful guide to researchers and diagnosticians identifying important cyst nematodes from the genus Punctodera.

Technical Abstract: Punctodera mulveyiensis n. sp. is described and illustrated from turf grass (Poa annua) in golf course greens with other fescues in Bandon, Coos County, Oregon. Females and cysts are characterized with a saccate, globose to ovoid or pear-shaped body tapering to a protruding neck. The cuticle has a lacelike pattern of ridges and heavy punctations on the subsurface. Cysts have distinctive vulval and anal circumfenestra patterns with heavy bullae scattered around the fenestra area which are lacking in young cysts. Second-stage juveniles (J2) are vermiform tapering to a long and cylindrical tail with a bluntly rounded to occasionally clavate tail terminus and lateral fields with four lines. Morphologically, this new specie resembles all other know species in Punctodera including P. stonei, P. chalcoensis, P. punctata and P. matadorensis. However, with the light microscopy (LM) and scanning electron microscopy (SEM) observations, it differs from these species either by the body and stylet length, shape of head, tail and tail terminus of J2, female and male stylet or spicule lengths, and in having distinctive vulval and anal circumfenestra patterns in cysts. The younger cysts are without bullae and older cysts have heavy bullae that are scattered around the circumfenestra area. Molecular analysis with sequence alignments and phylogenetic trees of ITS rDNA, nuclear heat shock protein 90 and mitochondrial COI sequences separated P. mulveyiensis n. sp. from P. matadorensis, P. punctata, P. stonei, and P. chalcoensis, but 18S and 28S were relatively conserved with a few bp differences and lacked sufficient Punctodera species sequences to strongly support a new species designation. A morphologically most closely related species P. stonei collected from Canada was studied and sequenced, and further supported the new species status of P. mulveyiensis n. sp. An identification key to all five species of Punctodera is given.