First Report of Root-Knot Nematode Meloidogyne hispanica Infecting Grapevines in Southern Spain

Abstract

Some commercial vineyards producing the ‘Condado de Huelva’ wine denomination of origin in Almonte, Bonares, and Rociana (Huelva Province), southern Spain, showed general decline in sandy soils in 2009. Disease surveys revealed severe infections of grapevine rootstock Richter 110 feeder roots and heavy soil infestations by a root-knot nematode (Meloidogyne sp.). Infected plants showed a general decline as the only visible aboveground symptom, but when roots were inspected, moderate to small galls on secondary feeder roots were detected. The Meloidogyne sp. population was extracted and quantified from soil and root samples as previously described (1) and identified by the female perineal pattern, esterase (Est) and malate dehydrogenase (Mdh) phenotypes, and sequencing and maximum parsimony (MP) analysis of the ribosomal DNA region D2-D3 of 28S (2,4). Morphology of the perineal patterns and measurements of the second-stage juveniles (J2s) matched those of the original description of Meloidogyne hispanica (3). Enzyme analysis revealed two slow and a medium Est bands, a strong band, and two additional weaker bands coincident with the S2-M1 and N3 Mdh M. hispanica phenotypes (2,4). D2-D3 sequences of all three populations sampled were 100% homologous (GenBank Accession No. GQ375158). Phylogenetic analyses with MP of those sequences placed the Meloidogyne sp. in a clade (100% support) that included all M. hispanica sequences available from the GenBank database (4). M. hispanica was first found in Seville Province, southern Spain, infecting rootstocks of Prunus spp. Its distribution has been confirmed worldwide on different agricultural crops. Thus, M. hispanica has been reported to be infecting grapevines in South Africa and Australia (4); however, to our knowledge, this is the first report of M. hispanica infecting grapevines in Europe. Our data suggest that M. hispanica may pose a threat for vineyard production in southern Spain since M. hispanica was found in 52.63 and 47.36% of soil and root samples, respectively, from 19 fields in ‘Condado de Huelva’, with nematode population densities ranging from 2.4 to 129.6 eggs and J2s per 100 cm3 of soil and 1 to 1,797 eggs and J2s per gram of fresh roots. Furthermore, genes that confer resistance to other common root-knot nematodes reported on grapevine in Europe may not protect against M. hispanica. References: (1) K. R. Barker. Nematode extraction and bioassays. Page 19 in: An Advanced Treatise on Meloidogyne. Vol. II, Methodology. K. R. Barker et al., eds. North Carolina State University Graphics, Raleigh, 1985. (2) P. R. Esbenshade and A. C. Triantaphyllou. J. Nematol. 22:10, 1990. (3) H. Hirschmann. J. Nematol. 18:520, 1986. (4) B. B. Landa et al. Plant Dis. 92:1104, 2008.