Abstract

ROSAS-HERNANDEZ, Leonel et al. Detection, identification and phylogenetic inference of the stem nematode Ditylenchus dipsaci (Kuhn) filipjev (Nematoda:Anguinidae) affecting alfalfa Medicago sativa L. in Jalisco, Mexico. Rev. mex. fitopatol [online]. 2017, vol.35, n.3, pp.377-396. ISSN 2007-8080.  https://doi.org/10.18781/r.mex.fit.1703-8.

Monitoring regulated pests and diseases that affect crops in Mexico is important to determine its presence and impact. With the purpose of supporting the National Phytosanitary Epidemiological Surveillance System activities, alfalfa plants from Atoyac, Jalisco showing stunting, shortened internodes, buds and leaves deformed as well as change leaf coloration, suspicious symptoms produced by foliar nematodes were analyzed. Roots, leaves + buds and stems tissues were analyzed separately. Classical taxonomy, molecular and phylogenetic analysis of two ribosomal DNA markers were performed on specimens detected. Ditylenchus genus specimens were detected and isolated only in leaves + buds and stems. The species identity based on females and males morphotaxonomy belonged to the stem nematode D. dipsaci. The PCR-RFLP restriction pattern of ITS1-5.8S-ITS2 displayed by RsaI enzyme was 335, 280, 200, and 132 bp, while for the enzyme HinfI the pattern was 400 and 300 bp. The BLASTING aligment showed 99% homology with D. dipsaci (E=0.0). The phylogenetic reconstruction of both markers according the bayesian posterior probabilities criteria placed the alfalfa mexican population within the clade that includes several D. dipsaci sensu stricto populations. To our knowledge, this is the first report of D. dipsaci affecting alfalfa in western Mexico.

Keywords : Phytosanitary surveillance; taxonomy; phylogeny; molecular; ribosomal DNA.

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