Genetic diversity of Meloidogyne spp. parasitising potato in Brazil and aggressiveness of M. javanica populations on susceptible cultivars

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.

Plant Disease ◽  
1997 ◽  
Vol 81 (2) ◽  
pp. 217-221 ◽  
Author(s):  
J. C. Veremis ◽  
G. B. Cap ◽  
P. A. Roberts

Accessions of Lycopersicon cheesmanii, L. chmielewskii, L. esculentum var. cerasiforme, L.hirsutum, L. parviflorum, L. peruvianum, L. pennellii, L. pimpinellifolium, and three interspecific hybrids of L. peruvianum with L. esculentum, were screened for resistance to the false root-knot nematode (Nacobbus aberrans) in greenhouse tests. Variability in nematode reproduction levels was observed within L. chmielewskii accessions LA 2695 and LA 2663 in initial tests with N. aberrans from Argentina; however, interspecific hybrids of L. esculentum cv. UC-82 × L. chmielewskii LA 2695, L. esculentum cv. UC-82 × L. chmielewskii LA 2663, and all the parent plants were susceptible in subsequent tests to the isolate of N. aberrans from Argentina and to an isolate from Mexico. The interspecific hybrids that possess the gene Mi and additional novel resistance to Meloidogyne spp. (root-knot nematodes) and all other exotic tomato accessions tested were susceptible to N. aberrans in our tests. Thus, we have been unable to identify or confirm resistance to two N. aberrans isolates in a range of Lycopersicon germ plasm accessions, including those that possess genes for resistance to root-knot nematodes.


1998 ◽  
Vol 76 (1) ◽  
pp. 75-82
Author(s):  
J G Van der Beek ◽  
PFG Vereijken ◽  
L M Poleij ◽  
C H Van Silfhout

To study virulence and aggressiveness in root-knot nematodes on cultivars of potato (Solanum tuberosum L., four isolates of Meloidogyne hapla Chitwood race A, one of M. hapla race B, three of Meloidogyne chitwoodi Golden et al., and two of Meloidogyne fallax Karssen were evaluated on 10 commercial potato cultivars under semisterile conditions in Petri dishes. Virulence and aggressiveness were assessed in terms of nematode reproduction by egg-mass index and reproduction factor, estimated by the number of egg masses and juveniles produced, respectively, divided by the number of juveniles inoculated. Significant interaction for both parameters was revealed between species of Meloidogyne and potato cultivars. Only M. hapla showed significant isolate-by-cultivar interaction, which was predominantly caused by the M. hapla race B isolate Hh. This indicates variation in virulence and suggests the occurrence of different genetic factors for virulence and resistance in M. hapla isolates and potato cultivars, respectively. Despite large differences, the observed levels of resistance were too low to be of practical meaning for breeding, with the exception of resistance to isolate Hh. No significant differences were obtained between isolates of M. chitwoodi and M. fallax or isolate-by-cultivar interaction, indicating neither variation in aggressiveness nor in virulence in the isolates used. A comparative greenhouse experiment gave comparable results for egg-mass index but contradicting results for reproduction factor, most likely because of differences in life cycle, which appeared to be shorter in M. fallax than in M. hapla and M. chitwoodi. The Petri-dish method proved to be accurate for virulence studies of root-knot nematodes on potato culitvars. Meloidogyne fallax was most aggressive on potato, followed by M. chitwoodi, M. hapla race A, and finally by M. hapla race B. Key words: aggressiveness, biadditive model, biplot, plant breeding, resistance, virulence.


2018 ◽  
Vol 20 (1) ◽  
pp. 11-16
Author(s):  
MUTALA’LIAH MUTALA’LIAH ◽  
SIWI INDARTI ◽  
ARIF WIBOWO

Mutala’liah, Indarti S , Wibowo A. 2019. Short Communication: The prevalence and species of root-knot nematode which infect on potato seed in Central Java, Indonesia. Biodiversitas 20: 11-16. Root-knot nematodes are considered as one of the most destructive pathogens of potatoes, especially on tuber seed. Infected potato seed will cause tuber malformation and the most important thing is as the main spreading source of Meloidogyne spp. The objective of this research was to know the prevalence and identify the species of root-knot nematode which attack the potato seed in four sub-districts of potato production centre in Central Java, Indonesia. Molecular and morphological identification was conducted for the nematode species identification. PCR assay using MIG primer to detect three tropical root-knot nematodes followed by sequencing was conducted for molecular detection, while the perennial pattern was conducted for morphological detection. Results showed that root-knot nematodes on potato seed were generally distributed in Central Java with the prevalence percentage between 14.28-88.23% on the three from four sampling area. The molecular and morphological identification show that species of root-knot nematodes identified on potato seeds were Meloidogyne javanica, M. incognita, and M. arenaria.


2015 ◽  
Vol 33 (2) ◽  
pp. 147-150
Author(s):  
Érika CSS Correia ◽  
Norberto Silva ◽  
Marylia GS Costa ◽  
Silvia RS Wilcken

Lettuce is the main vegetable cultivated in Brazil, in volume and in marketed value. There are ranges of diseases which may affect lettuce crops, including those caused by root-knot nematodes (Meloidogyne spp.). We evaluated the reproductive potential of Meloidogyne enterolobii in 22 lettuce cultivars. The plants were inoculated with 5,000 eggs and eventuals second stage juveniles of nematode per pot, two days after the transplanting. 'Rutgers' tomato was used as standard for inoculum viability of M. enterolobii. We evaluated, 60 days after inoculation, the gall index, egg mass index and reproduction factor (RF). The 'Ithaca', 'Raider Plus', 'RS-1397', 'L-104', 'Challenge', 'IP-11', 'Classic', 'Salinas 88', 'Vanguard 75', 'Calona' and 'Desert Queen' were resistant to M. enterolobii with RF varying from 0.22 to 0.9, and the cultivars Lady Winterset, Robinson, Sonoma, Raider, Lucy Brown, Bnondaga, Summer Time, Taina, Sundevil and L-109 were susceptible to this nematode, with RF ranging from 1.06 to 5.73.


Nematology ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 373-380
Author(s):  
Santino A. Silva ◽  
Anderson C.G. Bicalho ◽  
Débora C. Santiago ◽  
Lucas S. Cunha ◽  
Andressa C.Z. Machado

Summary One of the concerns for nematological research is the absence of information on standard nematode population densities to be used when screening to assess resistance/susceptibility levels of a genotype. In addition, the length of the growth period, especially for perennial crops such as coffee, must also be known. The objective of this work was to evaluate the ideal evaluation periods and population densities of the root-knot nematode, Meloidogyne incognita, for phenotyping Coffea arabica genotypes. Seedlings of coffee ‘Mundo Novo’ with five leaf pairs cropped in 700 cm3 plastic pots were inoculated with population densities of 700, 1400, 2800, 5600 and 11 200 eggs of M. incognita per plant and evaluated at 90, 120, 150 and 180 days after inoculation (DAI) to determine the nematode reproduction factor (RF). The use of population densities of M. incognita from 700-2000 nematodes with evaluations between 90 and 180 DAI was the most suitable to obtain higher RF values and allows earlier and more accurate evaluations, which reduces the time for phenotyping in genetic screening programmes.


2017 ◽  
Vol 107 (6) ◽  
pp. 681-691 ◽  
Author(s):  
Janja Lamovšek ◽  
Barbara Gerič Stare ◽  
Irena Mavrič Pleško ◽  
Saša Širca ◽  
Gregor Urek

The increased incidence of the crown gall disease caused by Agrobacterium tumefaciens has long been associated with activities of root-knot nematodes (Meloidogyne spp.). Pot experiments on tomato were designed to assess plant vitality, nematode reproduction, and crown gall incidence in combined infection with Agrobacterium and Meloidogyne spp. on tomato roots. Results suggest that tomato plants infected with pathogenic A. tumefaciens 2 days before the nematodes show enhanced plant defense against M. ethiopica resulting in lower egg and gall counts on roots 45 and 90 days postinoculation (dpi); no significantly enhanced defense was observed when the plant was inoculated with bacteria and nematodes at the same time. Split-root experiments also showed that the observed interaction was systemic. Reverse-transcription quantitative polymerase chain reaction analysis that targeted several genes under plant hormonal control suggests that the suppression was mediated via systemic acquired resistance by the pathogenesis-related protein 1 and that M. ethiopica did not enhance the defense reaction of tomato against Agrobacterium spp. Nematodes completely inhibited tumor growth in a 45-day experiment if inoculated onto the roots before the pathogenic bacteria. We conclude that the observed antagonism in the tested pathosystem was the result of initially strong plant defense that was later suppressed by the invading pathogen and pest.


2020 ◽  
Vol 36 (6) ◽  
Author(s):  
Gabriela Silva Thomazelli ◽  
Roberta Luiza Vidal ◽  
Lúcio Roberto Vizentini ◽  
Daniel Dalvan Do Nascimento ◽  
Renato Silva Soares ◽  
...  

Brazil is currently the world’s largest producer and exporter of sugarcane, and the crop has high socioeconomic importance in the country. Root-knot nematodes (Meloidogyne spp.) are one of the major limiting factors in sugarcane production. These plant parasites have wide geographic distribution, high damage potential, and are difficult to control. Recently, the species Meloidogyne enterolobii was identified in sugarcane crops in the state of Pernambuco, Brazil. Given the importance of genetic resistance for integrated nematode management and the lack of research on the M. enterolobii–sugarcane pathosystem, this study aimed to assess the response of sugarcane cultivars to M. enterolobii. Thirteen cultivars were evaluated for their resistance to M. enterolobii based on the nematode reproduction factor. The experiment was conducted in a greenhouse, in a completely randomized design, with 14 replicates. Pre-sprouted sugarcane seedlings were transplanted to 5 L pots, and each pot was considered an experimental unit. At 15 days after transplanting, the seedlings were inoculated with 5,000 eggs and second-stage juveniles of M. enterolobii. Tomato and okra plants were also inoculated to test the viability of the inoculum. At 240 days after inoculation, plant roots were processed and evaluated for nematode number. This parameter was used to calculate the nematode reproduction factor on each cultivar. All sugarcane cultivars were found to be immune to M. enterolobii, with a reproduction factor of 0.


2020 ◽  
Vol 38 (2) ◽  
pp. 126-133
Author(s):  
Paula Andrea O Carmona ◽  
Jadir B Pinheiro ◽  
Geovani Bernardo Amaro ◽  
Giovani Olegario da Silva ◽  
José Ricardo Peixoto ◽  
...  

ABSTRACT One of the main obstacles for food production in many developing countries, as in Brazil, is the damage caused by root-knot nematodes, mainly those belonging to the genus Meloidogyne. This study aimed to assess the resistance levels of 44 sweet potato genotypes to M. javanica, M. incognita race 1 and M. enterolobii. These researches were carried out in 2014, under greenhouse conditions in Brasília-DF, Brazil. A completely randomized design with six replicates of one plant/plot/treatment was used. We determined the gall index (GI) and egg mass index (EMI) in the root system of each plant, the number of eggs and juveniles per gram of root with galls and the nematode reproduction factor. M. javanica was less aggressive and reproduced in only 9.09% of the evaluated genotypes; M. incognita race 1 was intermediate (47.73%); whereas M. enterolobii was more aggressive, with a population increase in 79.55% of the genotypes. The genotypes CNPH 1200, CNPH 1219, CNPH 1292, CNPH 1392, CNPH 60 and ‘Coquinho’ were the most resistant to the three species and can be used in breeding programs for multiple resistance to root-knot nematodes.


Plant Disease ◽  
2005 ◽  
Vol 89 (5) ◽  
pp. 527-527
Author(s):  
G. T. Church

The state of Florida is the largest producer of fresh market tomato (Lycopersicon esculentum L.) in the United States with 2003 yields of 634 million kg on 17,700 ha valued at 516 million dollars. Effective crop management is essential for production of vegetables in Florida because of the presence of intense pest pressure. The identification of the pests present is the first step in the development of a successful IPM (integrated pest management) program. Root-knot nematodes (Meloidogyne spp.) are common nematodes that parasitize vegetables in Florida and cause significant yield reductions when not properly managed. In 2003 field experiments, soil was collected from two research farms in Saint Lucie and Seminole counties in Florida. Galling caused by root-knot nematode was observed on tomato at both locations. Since females suitable for identification are difficult to obtain from field-grown roots, field soil was placed in pots in the greenhouse and planted with Lycopersicon esculentum cv. Rutgers. Standard morphological techniques, differential host tests, and isozyme phenotypes were used in nematode identification. Female root-knot nematodes were extracted from tomato roots and placed in extraction buffer (10% wt/vol sucrose, 2% vol/vol Triton X-100, 0.01% wt/vol bromophenol blue). The females were crushed, loaded on a polyacrylamide gel, and separated by electrophoresis using the PhastSystem (Amersham Biosciences, Piscataway, NJ). The activities of malate dehydrogenase and esterase enzymes were detected using standard techniques. Isozyme phenotypes consistent with Meloidogyne incognita (Kofoid and White) Chitwood and M. javanica (Treub) Chitwood as well as with the newly described M. floridensis Handoo (1) were observed at both locations. To our knowledge, this is the first report of M. floridensis naturally occurring on tomato in Florida. The identification and distribution of M. floridensis in vegetable production fields is important for disease management throughout the state since the host range is likely different from other Meloidogyne spp. Reference: (1) Z. A. Handoo et al. J. Nematol. 36:20, 2004.


2021 ◽  
Vol 25 (02) ◽  
pp. 271-276
Author(s):  
Wentao Wu

Root-knot nematodes (Meloidogyne spp.) are soil-borne pathogens that can cause severe damage to agricultural production. The most common approaches to prevent root-knot nematode infections are based on crop rotation with non-host plants, use of chemical insecticides, biological control methods, and use of nematode-antagonistic or trap plants. Marigolds (Tagetes erecta) are used as nematode-killing plants, but there is controversy over the mechanism through which they control root-knot nematodes. This study confirmed that marigold root-exudates are lethal to root-knot nematodes, illustrated that marigolds act as trap plants for root-knot nematodes when planted close to nematode host plants such as tomato. We investigated the rates of infection and development of nematode larvae injected into the marigold root system to evaluate whether marigolds could act as a non-host plant for root-knot nematodes. We found that aqueous solutions of marigold root-exudates showed strong lethal and inhibitory effects on sec-stage juveniles and eggs of root-knot nematodes. Marigold roots secreted substances that attracted nematodes from the surrounding environment. Furthermore, marigold root cells contained substances that had a strong inhibitory effect on the development of root-knot nematodes, resulting in diapause in nematodes, and inhibition of further infection. Herein we report a preliminary exploration of the antagonistic mechanism in marigolds for controlling the growth and development of root-knot nematodes. Our research provides basis for promoting the use of marigold for the control of nematodes as an important part of sustainable cropping strategies that rely on biological pest control. © 2021 Friends Science Publishers


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