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

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 1AE5-2 times longer than the 'normal race', stylet delicate (11AE5-13AE0 lm long) with knobs distinctly sloping backwards, and long post-vulval uterine sac (81-150 lm 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.

A new stem nematode, Ditylenchus oncogenus n. sp. (Nematoda: Tylenchida), parasitizing sowthistle from Adriatic coast dunes in southern Italy

“…from D. gigas, D. dipsaci and other known Ditylenchus species, and are congruent with previous findings (Subbotin et al, 2004(Subbotin et al, , 2005Chizhov et al, 2010;Vovlas et al, 2011;Oliveira et al, 2013). Although D. oncogenus n. sp.…”

Morphological and molecular charaterisation of Pratylenchus parazeae n. sp. (Nematoda: Pratylenchidae) parasitizing sugarcane in China

“…In general, the definition of cryptic species is narrower. Some plant-parasitic nematodes cryptic species have been recognized, e.g., Ditylenchus dipsaci (Kühn 1857) Filipjev 1936and D. gigas Vovlas et al 2011(Vovlas et al 2011, P. f l o r i d e n s i s D e L u c a e t a l . 2 0 1 0 a n d P. parafloridensis De Luca et al 2010(De Luca et al 2010, P. coffeae (Zimmermann 1898) Filipjev and Schuurmans Stekhoven 1941and P. speijeri De Luca et al 2012(De Luca et al 2012.…”

Identificación y Análisis Filogenético del Nematodo Foliar Orrina phyllobia Afectando

“…La reacción de la PCR para los iniciadores D2A y D3B comprendió 5 µl de solución amortiguadora de PCR 10X, 3 µl de MgCl 2 50mM, 1 µl mix de DNTP´s 10mM, 2 µl de cada iniciador 10 µM, 0.5 µl de Taq polimerasa 5U/µl, 5 µl de extracción de ADN y 31.5 µl de H 2 O libres de ADNasas y ARNasas. Las condiciones de la amplificación fueron las siguientes: desnaturalización inicial de 95 °C durante 3 min, seguido de 35 ciclos de 95 °C durante 0.45 min, 55 °C durante 0.45 min y 72 °C durante 1 min, y finalmente con un ciclo a 72 °C durante 5 min (Vovlas et al, 2011). Se utilizó un termociclador i-Cycler (BIO-RAD) para todas las reacciones.…”

“…The PCR reaction for primers D2A and D3B included 5 µl of PCR buffer solution 10X, 3 µl of MgCl 2 50mM, 1 µl mix of DNTP's 10mM, 2 µl of each initiator 10 µM, 0.5 µl of Taq polymerase 5U/µl, 5 µl of DNA extraction ADN and 31.5 µl of H 2 O, free of DNAses and RNAses. The conditions for the amplification were as follows: initial denaturation at 95 °C for 3 min, followed by 35 cycles at 95 °C for 0.45 min, 55 °C for 0.45 min, and 72 °C for 1 min, and finally, one cycle at 72 °C for 5 min (Vovlas et al, 2011). An i-Cycler (BIO-RAD) thermocycler was used for all reactions.…”