scholarly journals New Data Completing the Spectrum of the Ma, RMia, and RMja Genes for Resistance to Root-Knot Nematodes (Meloidogyne spp.) in Prunus

2019 ◽  
Vol 109 (4) ◽  
pp. 615-622 ◽  
Author(s):  
Henri Duval ◽  
Cyril Van Ghelder ◽  
Ulysse Portier ◽  
Carole Confolent ◽  
Pablo Meza ◽  
...  

Root-knot nematodes (RKN) (Meloidogyne spp.) are worldwide pests that affect a considerable number of plants, among which stone fruit (Prunus spp.) are severely attacked. Prevalent RKN species are Meloidogyne arenaria, M. incognita, and M. javanica in stone fruit but the emergent M. ethiopica and M. enterolobii are also reported to challenge perennial crops. In Prunus spp., the complete-spectrum resistance (R) gene Ma from plum and the more restricted-spectrum R genes RMia from peach and RMja from almond completely inhibit nematode multiplication and gall formation of the RKN species that they control. This study aimed to update the resistance spectra of these three major genes by evaluating their activity toward one isolate of the yet-untested RKN species mentioned above. To state whether a given gene controls a particular species, the principle of our experiment was to genotype with appropriate markers a number of individuals segregating for this gene and then to phenotype these individuals. A perfect matching of the genotype and the phenotype of individuals indicates that the gene of interest is active against and, thus, controls the corresponding isolate of this RKN species. Segregating materials used were an Ma F1 plum progeny, an RMia F2 peach progeny, and an RMja F2 almond progeny. In addition to previous data, our results establish a clear spectrum for each of the three genes toward isolates from both the three prevalent species and the two emerging species. Ultimately, our results reveal that (i) Ma controls all of them, (ii) RMja controls all species except M. incognita and M. floridensis, and (iii) RMia controls M. arenaria, M. incognita, and M. ethiopica but not M. javanica or M. enterolobii. Our data should have wide implications for RKN resistance management and breeding and for deciphering the molecular mechanisms of the spectrum of RKN R genes.

Nematology ◽  
2002 ◽  
Vol 4 (5) ◽  
pp. 605-608 ◽  
Author(s):  
Philippe Castagnone-Sereno

AbstractRoot-knot nematodes (RKN) of the genus Meloidogyne constitute the most widely distributed and damaging group of plant-parasitic nematodes. Plant resistance (R) is currently the most effective and environmentally safe method to control these pests. The mode of reproduction of the major species, i.e., apomictic (= mitotic) parthenogenesis, should theoretically lead to clonal progenies. However, the recent emergence of new virulent biotypes, able to overcome plant R genes, indicates that variability does exist in these organisms. Experiments showed that selection for virulence was possible in RKN, which has important consequences for the management and durability of natural R genes in the field. To understand the molecular mechanisms involved in such selection, we have developed a differential strategy based on the comparative analysis of pairs of RKN near-isogenic lineages and recent results obtained in the laboratory are presented. Understanding how the genome of these nematodes is modified in response to the selective pressure of a plant R gene should provide further data on the putative role of non-meiotic events leading to stable genetic variation in these apomictic organisms.


Nematology ◽  
2017 ◽  
Vol 19 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Israel L. Medina ◽  
Cesar B. Gomes ◽  
Valdir R. Correa ◽  
Vanessa S. Mattos ◽  
Philippe Castagnone-Sereno ◽  
...  

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.


2013 ◽  
Vol 103 (8) ◽  
pp. 833-840 ◽  
Author(s):  
Samira Khallouk ◽  
Roger Voisin ◽  
Ulysse Portier ◽  
Joël Polidori ◽  
Cyril Van Ghelder ◽  
...  

Root-knot nematodes (RKNs) (Meloidogyne spp.) are highly polyphagous pests that parasitize Prunus crops in Mediterranean climates. Breeding for RKN-resistant Prunus cultivars, as an alternative to the now-banned use of nematicides, is a real challenge, because the perennial nature of these trees increases the risk of resistance breakdown. The Ma plum resistance (R) gene, with a complete spectrum, and the RMia peach R gene, with a more restricted spectrum, both provide total control of Meloidogyne incognita, the model parthenogenetic species of the genus and the most important RKN in terms of economic losses. We investigated the durability of the resistance to this nematode conferred by these genes, comparing the results obtained with those for the tomato Mi-1 reference gene. In multiyear experiments, we applied a high and continuous nematode inoculum pressure by cultivating nematode-infested susceptible tomato plants with either Prunus accessions carrying Ma or RMia R genes, or with resistant tomato plants carrying the Mi-1 gene. Suitable conditions for Prunus development were achieved by carrying out the studies in a glasshouse, in controlled conditions allowing a short winter leaf fall and dormancy. We first assessed the plum accession ‘P.2175’, which is heterozygous for the Ma gene, in two successive 2-year evaluations, for resistance to two M. incognita isolates. Whatever the isolate used, no nematodes reproducing on P.2175 were detected, whereas galls and nematodes reproducing on tomato plants carrying Mi-1 were observed. In a second experiment with the most aggressive isolate, interspecific full-sib material (P.2175 × [‘Garfi’ almond × ‘Nemared’ peach]), carrying either Ma or RMia (from Nemared) or both (in the heterozygous state) or neither of these genes, was evaluated for 4 years. No virulent nematodes developed on Prunus spp. carrying R genes, whereas galling and virulent individuals were observed on Mi-1-resistant tomato plants. Thus, the resistance to M. incognita conferred by Ma in Prunus material in both a pure-plum and an interspecific genetic background, or by RMia in an interspecific background, appears to be durable, highlighting the value of these two genes for the creation of Prunus rootstock material.


Nematology ◽  
2000 ◽  
Vol 2 (8) ◽  
pp. 907-916 ◽  
Author(s):  
Ngo Thi Xuyen ◽  
Raf Verlinden ◽  
Ruth Stoffelen ◽  
Dirk De Waele ◽  
Rony Swennen

AbstractTwenty-five banana varieties of section Eumusa (AA-group) and seven of the section Australimusa (Fe'i-group) from Papua New Guinea were evaluated for resistance to Radopholus similis, Pratylenchus coffeae and Meloidogyne spp. The host plant responses were compared with the susceptible reference cvs Grande Naine and Cavendish 901. In vitro propagated plants were transferred to the glasshouse in loamy sand and inoculated with approximately 1000 migratory endoparasitic nematodes at 4 weeks after planting. Reproduction of R. similis and P.coffeae in the roots was determined at 8 or 10 weeks, respectively, after inoculation. Reproduction of Meloidogyne spp. was determined 8 weeks after inoculation with 3300 to 5000 eggs. No resistance to R. similis was found in the diploid varieties. The Fe'i variety Rimina and possibly Menei were resistant to R. similis. All varieties tested were susceptible to P.coffeae and Meloidogyne spp. Tests de résistance de bananiers Eumusa et Australimusa (Musa spp.) envers les nématodes endoparasites migrateurs et galligènes - Vingt-cinq variétés de bananier de la section Eumusa (groupe AA) et sept de la section Australimusa (group Fe'i) provenant de Papouasie-Nouvelle Guinée ont été testées pour leur résistance envers Radopholus similis, Pratylenchus coffeae et Meloidogyne spp. Les résponses de ces variétés ont été comparées à celles des cultivars sensibles de référence Grande Naine et Cavendish 901. Des vitroplants ont été mis en place en serre sur un sol argilo-sableux et inoculés 4 semaines après plantation avec environ 1000 R. similis ou P.coffeae dont la reproduction a été déterminée 8 et 10 semaines, respectivement, après inoculation. La reproduction de Meloidogyne spp. l'a été 8 semaines après inoculation avec 3300 à 5000 oeufs. Aucune résistance à R. similis n'a été observée chez les variétés diploïdes. Les variétés du groupe Fe'i Rimina et Menei se sont montrées résistantes à R. similis, avec un certain doute dans le cas de la dernière. Toutes les variétés testées sont sensibles à P.coffeae et Meloidogyne spp.


2017 ◽  
Vol 63 ◽  
pp. 96-104 ◽  
Author(s):  
José Thalles Jocelino Gomes de Lacerda ◽  
Rodrigo Rodrigues e Lacerda ◽  
Nilson Antonio Assunção ◽  
Alexandre Keiji Tashima ◽  
Maria Aparecida Juliano ◽  
...  

1969 ◽  
Vol 45 (2) ◽  
pp. 55-84
Author(s):  
Jessé Román

An experiment was conducted to determine the nature of the pathogenic effects of five isolates of root-knot nematodes on the roots of the promising commercial sugarcane variety, Puerto Rico 980, the suitability of this sugarcane as a host for the five nematodes, and the possibility of the existence of strains in the species M. incognita acrita.


Plant Disease ◽  
2018 ◽  
Vol 102 (7) ◽  
pp. 1402-1409 ◽  
Author(s):  
Providence Moyo ◽  
Ulrike Damm ◽  
Lizel Mostert ◽  
Francois Halleen

Stone fruit trees (Prunus spp.) are economically important fruit trees cultivated in South Africa. These trees are often grown in close proximity to vineyards and are to a large extent affected by the same trunk disease pathogens as grapevines. The aim of the present study was to determine whether stone fruit trees are inhabited by Diatrypaceae species known from grapevines and whether these trees could act as alternative hosts for these fungal species. Isolations were carried out from symptomatic wood of Prunus species (almond, apricot, cherry, nectarine, peach, and plum) in stone fruit growing areas in South Africa. Identification of isolates was based on phylogenetic analyses of the internal transcribed spacer region and β-tubulin gene. Forty-six Diatrypaceae isolates were obtained from a total of 380 wood samples, from which five species were identified. All five species have also been associated with dieback of grapevine. The highest number of isolates was found on apricot followed by plum. No Diatrypaceae species were isolated from peach and nectarine. Eutypa lata was the dominant species isolated (26 isolates), followed by Cryptovalsa ampelina (7), Eutypa cremea (5), Eutypella citricola (5), and Eutypella microtheca (3). First reports from Prunus spp. are E. cremea, E. citricola, and E. microtheca. Pathogenicity tests conducted on apricot and plum revealed that all these species are pathogenic to these hosts, causing red-brown necrotic lesions like those typical of Eutypa dieback on apricot.


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