Meloidogyne arenaria

About: Meloidogyne arenaria is a research topic. Over the lifetime, 736 publications have been published within this topic receiving 14927 citations.

Identification of Meloidogyne incognita, M. javanica and M. arenaria using sequence characterised amplified region (SCAR) based PCR assays

Abstract: Three randomly amplified polymorphic DNA (RAPD) markers, OPA-12 420 , OPB-06 1200 and OPA-01 700 , species specific to the root-knot nematode species Meloidogyne arenaria , M. incognita and M. javanica respectively, were identified. After sequencing these RAPD-PCR products, longer primers of 18 to 23 nucleotides were designed to complement the terminal DNA sequences of the DNA fragments. This resulted in three pairs of species specific primers that were used to amplify the sequence characterised amplified regions (SCARs). The developed sets of SCAR primers were successfully used in straightforward, fast and reliable PCR assays to identify M. incognita , M. javanica and M. arenaria . The length variant SCAR markers can be amplified from DNA from egg masses, second stage juveniles and females. This species identification technique is therefore independent of the nematode's life cycle stage. Moreover the SCAR-PCR assay was successfully applied using DNA extracts from infested plant material. The method has potential to be optimised for routine practical diagnostic tests facilitating the control of these economically important pest organisms. Identification de Meloigyne incognita, M. javanica et M. arenaria au moyen de l'amplification de regions de sequences caracteristiques (SCAR) par une technique PCR - Trois marqueurs d'ADN polymorphique amplifiee au hasard (RAPD) OPA-12 420 , OPB-O6 1200 et OPA-OI 700 , respectivement specifiques des especes de nematodes Meloidogyne arenaria , M. incognita et M. javanica , ont ete identifies. Apres le sequencage de ces produits RAPD-PCR, les amorces les plus longues de 18 a 23 nucleotides ont ete choisies pour completer les sequences terminales d'ADN des fragments d'ADN. Cela a conduit a trois paires d'amorces specifiques de l'espece, utilisees pour amplifier les regions des sequences caracteristiques (SCAR). Les lots d'amorces SCAR mis au point ont ete utilises avec succes lors d'essais directs, rapides et surs pour identifier M. incognita , M. javanica et M. arenia . Les marqueurs peuvent etre amplifies a partir de l'ADN des masses d'oeufs, des juveniles de deuxieme stade ou des femelles. Cette technique d'identification specifique est donc independante des differents etats de developpement du nematode. De plus la technique SCAR-PCR a ete appliquee avec succes a l'ADN extrait du materiel vegetal infeste. Cette methode presente des potentialites d'amelioration permettant d'envisager des tests pratiques d'identification de routine, facilitant ainsi le controle de ces parasites economiquement importants.

A polymerase chain reaction method for identification of five major meloidogyne species.

Abstract: A polymerase chain reaction (PCR) method for discriminating Meloidogyne incognita, M. arenaria, M. javanica, M. hapla, and M. chitwoodi was developed. Single juveniles were ruptured in a drop of water and added directly to a PCR reaction mixture in a microcentrifuge tube. Primer annealing sites were located in the 3' portion of the mitochondrial gene coding for cytochrome oxidase subunit II and in the 16S rRNA gene. Following PCR amplification, fragments of three sizes were detected. The M. incognita and M. javanica reactions produced a 1.7-kb fragment; the M. arenaria reaction, a 1.1-kb fragment; and the M. hapla and M. chitwoodi reactions resulted in a 0.52-kb fragment. Digestion of the amplified product with restriction endonucleases allowed discrimination among species with identically sized amplification products. Dra I digestions of the 0.52-kb amplification product produced a characteristic three-banded pattern in M. chitwoodi, versus a two-banded pattern in M. hapla. Hinf I digestion of the 1.7-kb fragment produced a two-banded pattern in M. javanica, versus a three-banded pattern in M. incognita. Amplification and digestion of DNA from juveniles from single isolates of M. marylandi, M. naasi, and M. nataliei indicated that the diagnostic application of this primer set may extend to less frequently encountered Meloidogyne species.

Root-knot nematodes ( Meloidogyne spp.) in Europe

Abstract: In Europe, root-knot nematodes are increasingly important. Out of more than 90 Meloidogyne species currently described, 23 have been found on the continent. In the cooler climates, Meloidogyne hapla , M. naasi , M. chitwoodi and M. fallax are prevalent. Meloidogyne arenaria , M. javanica and M. incognita are the most common species in warmer conditions of southern Europe, but also in glasshouses in northern Europe. Morphological identification of root-knot nematodes is difficult and time consuming; therefore, many research groups have been developing molecular techniques for identification of Meloidogyne species. Meloidogyne chitwoodi and M. fallax are quarantine organisms and subject to regulations, and the highly aggressive M. enterolobii has been added to the EPPO alert list. Differences between temperate and tropical Meloidogyne species and their prevalence in Europe imply the need for different management strategies in south and north Europe. Possible crop rotations for the control of root-knot nematodes are limited due to the wide host range of several important species. The banning of methyl bromide and restrictions on other fumigant pesticides in the EU have increased the application of biofumigation significantly in south Europe. The egg-parasitising fungus Paecilomyces lilacinus is commercialised in Germany and applied as dispersible granules for application in water. Intensive research is conducted on the egg-parasitising fungus Pochonia chlamydosporia , and the obligate parasitic bacterium Pasteuria penetrans. European research has paid much attention to resistance breeding and selection. The Mi gene of tomato is widely used but resistance-breaking populations of M. incognita and M. javanica have been reported in different countries.

Identification of Peanut Genotypes with Improved Drought Avoidance Traits

Abstract: Peanuts (Arachis hypogaea L.) are often subjected to drought during some period in the growing season. A large root system may improve the plant's ability to continue growth during a drought. During greenhouse and field screening trials for resistance to the peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood, race 1], 16 peanut genotypes were observed to have very large root systems. Using these 16 genotypes plus cultivars Florunner, Southern Runner, and germplasm line Tifton 8 as checks, several studies were conducted to evaluate these genotypes for drought avoidance characteristics. In the first study, root and shoot development were observed at 15-d intervals on plants grown from seed in sand-filled pots. In a second 2-yr study, selections were grown in the field under portable rain-exclusion shelters that created controlled periods of stress. In addition, the genotypes were also planted and observed in unsheltered naturally drought stressed field plots. In the sand-filled pot stu...