Genetic diversity of the root‐knot nematode Meloidogyne enterolobii and development of a SCAR marker for this guava‐damaging species

Abstract

The objectives of this work were to evaluate the genetic variability of Meloidogyne enterolobii by molecular markers, and develop species-specific molecular markers for application in detection. Sixteen M. enterolobii isolates from different geographical regions (Brazil and other countries) and hosts were used in this study. The identification and purification of the populations were carried out based on isoenzyme phenotype. The DNA amplification of the intergenic region (IGS) of the rDNA and of the region between the cytochrome oxidase subunit II (COII) and 16S rRNA genes (mtDNA) produced specific fragments of the expected size for this nematode, i.e. 780 and 705 bp, respectively. Intraspecific variability among the isolates was evaluated with three different neutral molecular markers: AFLP, ISSR and RAPD. The results showed a low level of diversity among the isolates tested, indicating that M. enterolobii is a genetically homogeneous root-knot nematode species. The RAPD method allowed the identification of a species-specific RAPD fragment for M. enterolobii. This fragment was cloned and sequenced, and from the sequence obtained, a set of primers was designed and tested. The amplification of a 520-bp-long fragment occurred only for the 16 isolates of M. enterolobii and not for the 10 other Meloidogyne species tested. In addition, positive detection was achieved in a single individual female, egg-mass and second stage juvenile of this nematode. This SCAR species-specific marker for M. enterolobii represents a new molecular tool to be used in the detection of this nematode from field samples and as a routine diagnostic test for quarantine devices.

Intraspecific variability of the facultative meiotic parthenogenetic root-knot nematode (Meloidogyne graminicola) from rice fields in Vietnam

“…For instance, M. chitwoodi, a meiotic parthenogenetic nematode, has a wide host range and has shown to have significant intraspecific variability and genetic structure between four populations from the USA [4]. In addition, several obligatory mitotic parthenogenetic nematodes having a larger host range were studied (e.g., M. enterolobii), and were characterized by a genetically homogeneous organization [5]. More exhaustive data then need to be generated to explore the potential contribution of each reproductive mode in the genetic structure organization and intraspecific variability.…”

Meloidogyne enterolobiireproduction on vegetable crops and plants used as green manure

“…), na China. Após alguns estudos (TIGANO et al, 2010;XU et al, 2004) foi verificado que M. enterolobii e M. mayaguensis (RAMMAH; HIRSCHMANN, 1988) que haviam sido relatadas em raízes de Solanum melongena, tratava-se da mesma espécie, resultando numa sinonímia entre esses dois nematoides. A alta taxa de reprodução e a ampla gama de hospedeiros evidencia a agressividade da espécie, capaz de superar fontes de resistência a outras meloidoginoses como M. incognita, M.…”

Detection of Meloidogyne enterolobii in potatoes in South Africa and phylogenetic analysis based on intergenic region and the mitochondrial DNA sequences

“…However, Tigano et al (2010) observed similar homogeneity displayed by M. enterolobii populations from different geographic regions in Brazil, thus, it is likely that the lack of variation within the South Phylogenetic analysis using ML for the IGS sequences of these samples showed that the South African M. enterolobii populations and those from GenBank formed an independent cluster with a high bootstrap support value of 90% (Fig.1). This cluster, containing our populations and M. enterolobii from GenBank, was distinct from others and was sandwiched between tropical species and that of cold/temperate adapted Meloidogyne species clusters.…”

“…In South Africa, it was first reported in Mpumalanga, in 1997 where it led to the decline and eventual death of infected but untreated guava trees (Willers, 1997). This nematode species has also been identified in various parts of the world, such as France, the USA (Florida), two greenhouses in Switzerland, Brazil and China (Blok et al, 2002;Brito et al, 2004;Kiewnick et al, 2009;Tigano et al, 2010;Hu et al, 2011).…”