Caracterización morfológica y molecular de nematodes picadores de la raíz (Longidorus spp.) sobre palmera datilera en Arizona, California y Florida

Abstract

Trabajo presentado en la 47th Annual Meeting of the Organization of Nematologists of Tropical America, celebrada en Varadero (Cuba) del 17 al 22 de mayo de 2015.For decades, ornamental growers in Florida have imported date palms (Phoenix dactylifera) from Arizona and California. Needle nematodes (Longidorus spp.) with conoid and hemispherical tails have been detected consistently in these imported palms in Florida. The populations with conoid tails have been identified routinely as Longidorus africanus and those with hemispherical tails as L. belloi, L. belondiroides, and L. orientalis. Recent molecular and morphological analyses have confirmed the identification of L. africanus and also that of L. orientalis, reported by R. Esser, in Florida, in 1995 on date palms from California. These findings disprove the reports of detection of L. belloi and L. belondiroides, not found again, and validate that of L. orientalisas a continental record in the United States and the Americas. Longidorus africanus is a known parasite of vegetables in Southern California, whereas L. orientalis is a parasite of date palm in the Middle East. The populations of L. orientaliscontained a few males, not reported in the original description. Longidorus orientalis was commonly found in association with L. africanus and was able to survive for at least four years, at low densities in warm and humid environments of Florida, on transplanted date palms imported from California and Arizona. Phylogenetic relationships of L. orientalis with closely related Longidorus species were reconstructed using D2-D3 of 28S rRNA, ITS1 rRNA, and partial coxI gene sequences. The PCR-D2-D3 of 28S rDNA-RFLP diagnostic profile was obtained and proposed for the identification of this species. Longidorus orientalis shows high intraspecific variation (up to 15.5%) in coxI mtDNA sequences. Incongruence between ITS1 rRNA and coxImtDNA gene trees was noticed from the analysis of phylogenetic relationships between L. orientalispopulations, indicating selective introgression of mtDNA through gene flow as a consequence of hybridization of populations from different origin.N