Root-knot nematodes (Meloidogyne spp.) significantly impact potato production worldwide and in Brazil they are considered one of the most important group of nematodes affecting potatoes. The objectives of this study were to survey Meloidogyne spp. associated with potatoes in Brazil, determine their genetic diversity and assess the aggressiveness of M. javanica on two susceptible potato cultivars. Fifty-seven root-knot nematode populations were identified using esterase phenotyping, including Meloidogyne javanica, M. incognita, M. arenaria and M. ethiopica. Overall, root-knot nematodes were present in ca 43% of sampled sites, in which M. javanica was the most prevalent species, and the phenotypes Est J3, J2a and J2 occurred in 91.2, 6.7 and 2.1% of the positive samples, respectively. Other species, such as M. incognita, M. arenaria and M. ethiopica, were found less frequently and occurred at rates of 6.4, 4.3 and 2.1% of the samples, respectively. Sometimes, M. javanica was found in mixtures with other root-knot nematodes in ca 10.6% of sites containing Meloidogyne. After confirming the identification of 17 isolates of M. javanica and one isolate each of M. incognita, M. arenaria and M. ethiopica by SCAR markers, the populations were used to infer their genetic diversity using RAPD markers. Results revealed low intraspecifc genetic diversity among isolates (13.9%) for M. javanica. Similarly, M. javanica sub-populations (J2a) clustered together (81% of bootstrap), indicating subtle variation from typical J3 populations. The aggressiveness of four populations of M. javanica from different Brazilian states on two susceptible potato cultivars was tested under glasshouse conditions. Results indicated differences in aggressiveness among these populations and showed that potato disease was proportional to nematode reproduction factor.
Characterization and phylogenetic analysis of 4 root-knot nematode species using DNA amplification fingerprinting and automated polyacrylamide-gel electrophoresis.
Molecular Plant-Microbe Interactions739-47.
Nematode parasites of potatoes. In:
Plant parasitic nematodes in temperate agriculture. Wallingford, UKCAB International pp.
Primeiro registro de Meloidogyne ethiopica Whitehead, 1968, em plantas de quivi no Brasil e reação em diferentes plantas cultivadas.
Identification and genetic diversity of Meloidogyne spp. (Tylenchida: Meloidogynidae) on coffee from Brazil, Central America and Hawaii.
Genetic diversity of the root-knot nematode Meloidogyne ethiopica and development of a species-specific SCAR marker for its diagnosis.
Meloidogyne species – a diverse group of novel and important plant parasites. In:
Root-knot nematodes. Wallingford, UKCAB International pp.
Genetic diversity of root-knot nematodes from Brazil and development of SCAR markers specific for the coffee-damaging species.
Reação de clones e cultivares de batata avaliados em casa de vegetação a Meloidogyne incognita, M. javanica e M. mayaguensis e in vitro a M. javanica.
Genetic variability and virulence of Meloidogyne incognita populations from Brazil to resistant cotton genotypes.
European Journal of Plant Pathology139195-204.
Cytogenetics, cytotaxonomy and phylogeny of root-knot nematodes. In:
An advanced treatise on MeloidogyneVol. 1. Raleigh, NC, USANorth Carolina State University Graphics pp.
Identification of Meloidogyneincognita, M. javanica and M. arenaria using sequence characterised amplified regions (SCAR) based PCR assays.