The quarantine root-knot nematode Meloidogyne enterolobii – a potential threat to Portugal and Europe

Abstract

In 2017, during a survey on subsistence farms and gardens in Coimbra region, Portugal, 40 infected root samples were collected and 47 root-knot nematode (RKN) isolates identified, based on esterase phenotype. The phenotypes A2, H1, Hi2/Hi4, I1/I2/I3 and J3 associated to five Meloidogyne species (M. arenaria, M. hapla, M. hispanica, M. incognita and M. javanica) were found in 43 RKN isolates. The esterase phenotype En2/En4/En5, corresponding to M. enterolobii (=M. mayaguensis), was detected in four RKN isolates from Cereus hildmannianus (Cactaceae), Lampranthus sp. (Aizoaceae), Physalis peruviana (Solanaceae) and Callistemon sp. (Myrtaceae) infected roots. In order to validate the biochemical identification of the M. enterolobii isolates, molecular studies performed with species-specific primers yielded the expected fragment of c.520 bp, and the amplification of cytochrome oxidase subunits I and II regions of 800 bp. The DNA sequences of one of the isolates were compared with available Meloidogyne species sequences in databases. The Portuguese isolate grouped with 99–100% bootstrap support with all M. enterolobii sequences included for comparison, confirming the presence of this RKN species in Portugal. In the EPPO region, M. enterolobii has been reported in France and Switzerland and intercepted in the Netherlands, Germany and the UK associated with plant material from Asia, South America and Africa. Taking into account the pathogen aggressiveness and its distribution, there is a high probability of its spread not only in the Mediterranean region but also in Europe, and of it becoming a threat to the agricultural economy, where there are no effective strategies for its control.