External secretions from the false root-knot nematode, Nacobbus aberrans

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.

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The structure of syncytia induced by the phytoparasitic nematode Nacobbus aberrans in tomato roots, and the possible role of plasmodesmata in their nutrition

Journal of Cell Science ◽

10.1242/jcs.23.1.299 ◽

1977 ◽

Vol 23 (1) ◽

pp. 299-313

Author(s):

M.G. Jones ◽

H.L. Payne

Keyword(s):

Light And Electron Microscopy ◽

Transformed Cells ◽

Root Knot Nematode ◽

Sieve Elements ◽

Tomato Roots ◽

Solute Movement ◽

Nacobbus Aberrans ◽

Symplastic Pathway ◽

Massive Accumulation

The structure of syncytia induced within galls in tomato roots by the false root-knot nematode Nacobbus aberrans has been examined by light and electron microscopy. A syncytium develops by breakdown or individual cell walls, which allows movement of cytoplasmic contents between transformed cells. The wall breakdown takes place at pit fields, where the plasmodesmata may be protected from digestion until the surrounding wall is removed. Numerous sieve elements differentiate in the cells outside the syncytium. These sieve elements, and also plasmodesmata in pit fields, are demonstrated by fluorescence microscopy. The possibility of a symplastic pathway of solute movement from the phloem to the syncytium is suggested. A massive accumulation of starch occurs in the gall cells and syncytial cells, which may be related to the proliferation of phloem. Wall ingrowths typical of transfer cells are absent, and a comparative survey of the structure and mode of solute entry into nematode-transformed cells in which ingrowths are present or absent is presented.

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Histopathology of roots of three tomato cultivars infected with two separate isolates of the false root-knot nematode Nacobbus aberrans

European Journal of Plant Pathology ◽

10.1007/s10658-016-1097-1 ◽

2016 ◽

Vol 148 (2) ◽

pp. 393-403 ◽

Cited By ~ 1

Author(s):

V. A. Cabrera ◽

N. Dottori ◽

M. E. Doucet

Keyword(s):

Root Knot Nematode ◽

Tomato Cultivars ◽

Nacobbus Aberrans

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Histopathology of Andean Potato (Solanum tuberosum Andigenum group) varieties parasitized by the false root-knot nematode, Nacobbus aberrans

Brazilian Journal of Biology ◽

10.1590/1519-6984.172401 ◽

2018 ◽

Vol 78 (4) ◽

pp. 679-685

Author(s):

M. del C. Tordable ◽

A. J. Andrade ◽

M. E. Doucet ◽

P. Lax

Keyword(s):

Solanum Tuberosum ◽

Close Association ◽

Central Zone ◽

Limiting Factors ◽

Root Knot Nematode ◽

Factors Affecting ◽

Hyperplastic Tissue ◽

Andean Potato ◽

Nacobbus Aberrans ◽

Histopathological Studies

Abstract Landraces of the Solanum tuberosum Andigenum group are abundant and diverse. They are a valuable genetic resource possessing resistance to pests, diseases, and environmental stresses. In the Andean region, populations of the false root-knot nematode Nacobbus aberrans became specialized to infect native potatoes, being one of the major limiting factors affecting this crop. A better understanding of the host plant-parasite interactions is important in order to select tolerant or resistant plants to be included in management programs. Despite the close of association of N. aberrans with potato, and the great diversity of the S. tuberosum Andigenum group, few histopathological studies have been conducted. The aim of this work was to analyze histological alterations induced by different Argentine populations of the nematode in naturally infested roots of four Andean potato varieties (Collareja, Negra Imilla, Ojo de Señorita and Colorada). All the varieties showed hyperplastic tissue in the central zone of galls, where syncytia developed in close association with the nematode female. Syncytia were composed of modified hyperplastic tissue and parenchyma xylem cells. The results showed differences among varieties in their response to nematode populations, with Ojo de Señorita and Negra Imilla being the most susceptible ones. This study is the first describing histopathological alterations induced by N. aberrans in susceptible Andean potato landraces.

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