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Tuyet N.T.,Vietnam Academy of Agricultural science VAAS | Elsen A.,Bodemkundige Dienst van Belgie | Nhi H.H.,Vietnam Institute of Agricultural Sciences | De Waele D.,Catholic University of Leuven | De Waele D.,North West University South Africa
Russian Journal of Nematology | Year: 2015

The in vivo reproduction of ten Prctylenchus coffeae populations, collected in different agroecological regions in Vietnam, on 13 agricultural crops was very similar. Of the 13 varieties of the 13 crops included in our study (one variety per crop), the varieties of banana, sugarcane, maize and upland rice were good hosts of P. coffeae. The soybean variety was a poor host and the varieties of groundnut, tomato, sweet potato, ginger, sesame, pineapple and citrus were very poor hosts or nonhosts of P. coffeae. The in vivo damage potential on the banana, coffee, sugarcane and maize varieties was very similar for all ten P. coffeae populations. All the P. coffeae populations were able to cause considerable damage to the vegetative growth of banana and coffee but not to sugarcane and maize. In view of the low reproduction on coffee, the extensive damage the P. coffeae populations caused on this agricultural crop is surprising and illustrates the high damage potential of P. coffeae on coffee. In general, there was similar in vivo reproduction on the 13 agricultural crops examined and in general, similar in vivo damage potential on banana, coffee, sugarcane and maize, indicating that the ten P. coffeae populations from Vietnam examined belong to the same pathotype.

Tuyet N.T.,Vietnam Academy of Agricultural science VAAS | Waeyenberge L.,Belgium Institute for Agricultural and Fisheries Research | Elsen A.,Bodemkundige Dienst van Belgie | Nhi H.H.,Food Crops Research Institute | And 2 more authors.
Russian Journal of Nematology | Year: 2014

Random amplified polymorphic DNA (RAPD) analysis of the complete genome and sequencing of the D2-D3 expansion segments of the 28S rDNA géhe were carried out to compare the intraspecific genomic variability of ten Prarylenchus coffeae populations collected from different agricultural crops in different agro-ecological regions in Vietnam. In addition, the RAPD bands were compared with these of P. speUeri, a species recently described from Ghana, while the D2-D3 sequences were compared with these of P. coffeae and closely related Prazylenchus species available in the GenBank database. As determined by RAPD bands analysis of the complete genome, genomic similarity did not correspond either with geographic or original host plant origin of the Vietnamese P. coffeae populations. As determined by sequence analysis of the D2-D3 28S rDNA expansion fragments, all ten P. coffeae populations from Vietnam examined were closely related to each other and with the P. coffeae populations of which the D2-D3 28S rDNA expansion fragments sequences were available from GenBank. Both the RAPD bands analysis of the complete genome and the sequence analysis of the D2- D3 28S rDNA expansion fragments indicate genetic divergence among the ten P. coffeae populations from Vietnam examined on the one hand and P. spe(jeri from Ghana on the other hand, confirming the validity of the latter species.

Thi Tuyet N.,Vietnam Academy of Agricultural science VAAS | Elsen A.,Bodemkundige Dienst van Belgie | Elsen A.,North West University South Africa | Huu Nhi H.,Vietnam Academy of Agricultural science VAAS | And 2 more authors.
Russian Journal of Nematology | Year: 2012

Ten Pratylenchus coffeae populations collected from different crops in different agroecological regions in Vietnam were compared on the basis of both light microscope and scanning electron microscope observations (morphological and morphometrical characters) to assess the intraspecific variability of these characters. The results revealed the presence of substantial variability in morphology and morphometry within and between these populations. However, these differences fall within the range of the morphological and morphometrical variability described previously in P. coffeae populations from other parts of the world. Our scanning electron microscopy observations further confirm that in P. coffeae there is a complete fusion of the 1st (lip) annulus with the oral disc resulting in an undivided en face view with no division between the lateral and median (sub-dorsal and sub-ventral) segments of the 1 st (lip) annulus. Although canonical discriminant analysis enabled the separation of the ten P. coffeae populations from Vietnam examined in three groups based on a combination of five morphological characters for the males, there was no relationship between these groups and their geographic origin or between these groups and the host plants from which they were originally isolated.

Vos C.,Catholic University of Leuven | Schouteden N.,Catholic University of Leuven | van Tuinen D.,CNRS Agroecology Lab | Chatagnier O.,CNRS Agroecology Lab | And 5 more authors.
Soil Biology and Biochemistry | Year: 2013

Arbuscular mycorrhizal fungi (AMF) have great potential as biocontrol organisms against the root-knot nematode Meloidogyne incognita which causes severe gall formation in plants, but knowledge about the underlying molecular mechanisms involved in the biocontrol of nematodes is scarce. In the present study, suppression subtractive hybridization (SSH) was used to investigate plant genes that are specifically up-regulated in tomato roots (Solanum lycopersicum cv. Marmande) pre-colonized by the AMF Glomus mosseae (BEG 12) and 12 days after soil inoculation with M. incognita juveniles. Nematode infection was significantly lower in the mycorrhizal roots as compared to the non-mycorrhizal roots, and identified genes were classified mainly in the categories of defense, signal transduction and protein synthesis and modification. The higher expression of a selection of defense-related plant genes specifically in the biocontrol interaction compared to in plants that were only mycorrhizal or only nematode-infected was confirmed, which pleads for the existence of mycorrhiza-induced priming of plant defense responses. In conclusion, by focusing on up-regulated gene expression in the biocontrol interaction between mycorrhizal tomato and M. incognita, new insights were found into the molecular mechanisms underlying the mycorrhiza-induced resistance against root-knot nematodes. In particular, the involvement of the phenylpropanoid pathway and reactive oxygen species (ROS) metabolism could explain the reduced root-knot nematode infection in mycorrhizal tomato roots, processes that have also been reported to play a pivotal role in plant resistance to nematodes. © 2013 Elsevier Ltd.

Vos C.M.,Catholic University of Leuven | Tesfahun A.N.,Catholic University of Leuven | Panis B.,Catholic University of Leuven | De Waele D.,Catholic University of Leuven | And 3 more authors.
Applied Soil Ecology | Year: 2012

Arbuscular mycorrhizal fungi (AMF) are able to protect plants against a range of soil-borne pathogens, but the biocontrol modes of action remain largely unknown, especially in the case of plant-parasitic nematodes. As a first step toward the elucidation of the modes of action, the interaction between the AMF Glomus mosseae and two nematode species with a different infection cycle was studied in tomato: the sedentary root-knot nematode Meloidogyne incognita and the migratory root-lesion nematode Pratylenchus penetrans. In greenhouse interaction experiments, nematode infection was investigated 8 weeks (M. incognita) or 10 weeks (P. penetrans) after nematode inoculation, in tomato roots either colonized by G. mosseae or not. The mycorrhiza-induced resistance was confirmed against both nematode species as the nematode population was significantly lower in mycorrhizal roots, with an overall reduction of 45% in the case of M. incognita and 87% for P. penetrans, although the latter nematode showed low infection numbers in tomato. In subsequently conducted split-root experiments, consisting of a two-compartment set-up, AMF were applied either locally (i.e. nematodes in the same compartment as AMF) or systemically (i.e. nematodes and AMF physically separated). The presence of AMF, either local or systemic, resulted in a significant infection reduction for both nematodes. The results show for the first time that infection by the root-knot nematode M. incognita and the root-lesion nematode P. penetrans is systemically reduced by G. mosseae. © 2012 Elsevier B.V.

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