<i>Pratylenchus</i> <i>vovlasi</i> sp. Nov. (Nematoda: Pratylenchidae) on Raspberries in North Italy with a Morphometrical and Molecular Characterization

oleh: Alberto Troccoli, Elena Fanelli, Pablo Castillo, Gracia Liébanas, Alba Cotroneo, Francesca De Luca

Format: Article
Diterbitkan: MDPI AG 2021-05-01

Deskripsi

Root-lesion nematode species rank third only to root-knot and cyst nematodes as having the greatest economic impact on crops worldwide. A survey of plant-parasitic nematodes associated with decaying raspberries (<i>Rubus</i> sp.) in northern Italy revealed that root-lesion nematodes were the most frequently occurring species among other phytonematodes. Several <i>Pratylenchus</i> species have been associated with <i>Rubus</i> sp. in Canada (Quebec, British Columbia) and USA (North Carolina, Maryland, New Jersey) including <i>P. penetrans</i> and <i>P. crenatus.</i> In the roots and rhizosphere of symptomatic raspberries, nematodes of two <i>Pratylenchus</i> spp. were detected. Detailed morphometrics of the two root-lesion nematode isolates were consistent with <i>Pratylenchus crenatus</i> and with an undescribed <i>Pratylenchus</i> species. The extracted nematodes were observed and measured as live and fixed materials and subsequently identified by integrative taxonomy (morphometrically and molecularly). The latter species is described herein as <i>Pratylenchus vovlasi</i> sp. nov., resulting morphometrically closest to <i>P. mediterraneus</i> and phylogenetically to <i>P. pratensis</i>. The molecular identification of <i>Pratylenchus vovlasi</i> sp. nov. was carried out by sequencing the ITS region, D2-D3 expansion domains of the 28S rRNA gene and a partial region of the nuclear <i>hsp90</i> gene. ITS-RFLP and sequence analyses revealed that <i>Pratylenchus vovlasi</i> sp. nov. had species-specific restriction profiles with no corresponding sequences present in the database. The phylogenetic relationships with ITS and D2-D3 sequences placed the <i>Pratylenchus vovlasi</i> sp. nov. in a clade with <i>P. pratensis</i> and <i>P. pseudopratensis</i>. This research confirms the occurrence of cryptic biodiversity within the genus <i>Pratylenchus</i> as well as the need for an integrative approach to the identification of <i>Pratylenchus</i> species.