Date Published: February 7, 2018
Publisher: Public Library of Science
Author(s): Samara Azevedo de Oliveira, Cláudio Marcelo Gonçalves de Oliveira, Carla Maria Nobre Maleita, Maria de Fátima A. Silva, Isabel Maria de Oliveira Abrantes, Silvia Renata S. Wilcken, Vitaly Citovsky.
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.
The turfgrass industry is expanding in Brazil and the biggest consumer market for turfgrass is the sports industry, mainly soccer fields and golf courses. The quality of the turf in these areas is crucial, especially on golf courses, where any imperfection can affect the outcome of the sport . There are about 110 official state-owned golf courses in Brazil, in addition to many private courses, each measuring ca. 50 ha .
Plant-parasitic nematodes, particularly Meloidogyne spp., are among the most damaging and difficult to manage agronomic pests. The identification of the RKN species is fundamental to effective crop management and quarantine control. However, its identification is difficult due to the high number of described species, morphological similarity between species and intraspecific variability.
Meloidogyne graminis was identified causing damage to golf course turfgrass in the State of São Paulo. This is the first report of this species in Brazil, being its differential diagnosis based on sequence analyses from the D2-D3 and mtDNA COII regions and on phylogenetic analyses.