Morphological and molecular characterization of Heterodera dunensis n. sp. (Nematoda: Heteroderidae) from Gran Canaria, Canary Islands.

Phougeishangbam Rolish Singh,Wim Bert,Gerrit Karssen,Marjolein Couvreur

doi:10.21307/jofnem-2020-098

Abstract

Heterodera dunensis n. sp. from the coastal dunes of Gran Canaria, Canary Islands, is described. This new species belongs to the Schachtii group of Heterodera with ambifenestrate fenestration, presence of prominent bullae, and a strong underbridge of cysts. It is characterized by vermiform second-stage juveniles having a slightly offset, dome-shaped labial region with three annuli, four lateral lines, a relatively long stylet (27-31 µm), short tail (35-45 µm), and 46 to 51% of tail as hyaline portion. Males were not found in the type population. Phylogenetic trees inferred from D2-D3 of 28S, partial ITS, and 18S of ribosomal DNA and COI of mitochondrial DNA sequences indicate a position in the ‘Schachtii clade’.

Highlights

The cysts forming nematodes of the genus Heterodera Schmidt, 1871 (Nematoda: Heteroderidae) are an economically important plant-parasitic nematode (PPN) group with a worldwide distribution and a broad host range causing prominent damages to the host plants ranging from stunted and reduced growth to wilting, chlorosis, and reduced root system (Perry et al, 2018; Sikora et al, 2018)
The vermiform second-stage juveniles (J2) of this PPN migrate in the root system of a host plant to feed on the vascular cylinder where they become obese sedentary females; subsequently, following fertilization and egg production, these females turn into protective cysts of more or less lemon shape, housing numerous embryonated eggs
These eggs can remain viable for years inside the cysts, until favorable environmental conditions initiate hatching of the cysts to continue further life cycle (Subbotin et al, 2010; Perry et al, 2018)

Summary

Introduction

The cysts forming nematodes of the genus Heterodera Schmidt, 1871 (Nematoda: Heteroderidae) are an economically important plant-parasitic nematode (PPN) group with a worldwide distribution and a broad host range causing prominent damages to the host plants ranging from stunted and reduced growth to wilting, chlorosis, and reduced root system (Perry et al, 2018; Sikora et al, 2018). 18S, 28S, Canary Islands, COI, Cyst nematode, ITS, Gran Canaria, Heterodera dunensis, Plant-parasitic nematodes, Schachtii, Systematics, Taxonomy.

Results

Conclusion