First report of Meloidogyne graminis on golf courses turfgrass in Brazil

Abstract

Plant-parasitic nematodes of the genus Meloidogyne, known as root-knot nematodes (RKN), have an important economic impact on golf course turfgrasses. The most prevalent RKN species associated with grasses are M. chitwoodi, M. graminicola, M. graminis, M. incognita, M. marylandi, M. microtyla, M. minor, M. naasi and M. sasseri. In 2010, slight thickening of the roots and RKN females with unusual features were observed in turfgrass roots on golf courses in Araras, São Paulo state, Brazil. This population (MgARA) was maintained in the lab and studied including morphological, morphometrical, biochemical and molecular markers. Morphology and morphometry were variable and not useful for identification, although perineal pattern morphology showed highly similarity with M. graminis description. Concerning to biochemical characterisation, the esterase phenotype Mg1, characterised by a very slow and fainter band, was detected in some protein homogenates. Regarding to molecular analysis, D2-D3 region of 28S rDNA gene and cytochrome oxidase subunit II region from mitochondrial DNA were amplified by PCR and sequenced. Phylogenetic analysis revealed that the Brazilian isolate, found associated with turfgrass, grouped with M. graminis isolates (98-99% bootstrap; variation of 8-11 and 0-24 bp, respectively), close to M. marylandi, supporting its identification as M. graminis. This is the first report of M. graminis on golf courses in Brazil.