Histology and Ultrastructural Modification Induced By Cyst Nematodes

Endo, B. Y.

doi:10.1007/978-1-4613-2251-1_7

Cited by 19 publications

(17 citation statements)

References 19 publications

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“…Plant‐parasitic cyst nematodes sercrete cell‐wall‐degrading enzymes and β‐expansins to achieve penetration of host plants (Davis et al ., 2000; Kudla et al ., 2005; Qin et al ., 2004). Once inside a plant the migratory juveniles breakdown cell walls and move about until they establish a permanent feeding site (Endo, 1986; Wyss and Zunke, 1986). In this paper, we report the finding and the functional characterization of the novel pectate lyase gene Gr‐pel2 from the potato cyst nematode G. rostochiensis , which probably assists the nematode in its migratory phase .…”

Section: Discussionmentioning

confidence: 99%

Structural and functional characterization of a novel, host penetration‐related pectate lyase from the potato cyst nematode Globodera rostochiensis

Kudla

Milac

Qin

et al. 2007

Molecular Plant Pathology

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SUMMARY The cell wall, a strong extraprotoplasmic layer surrounding plant cells that mainly consists of a variety of polysaccharides, constitutes a major barrier for potential parasites. Plant-parasitic nematodes are well equipped to overcome this barrier as they produce and secrete cell-wall-degrading enzymes. Expression profiling of various life stages of the potato cyst nematode Globodera rostochiensis revealed a novel pectate lyase gene (Gr-pel2, 759 bp). The Gr-PEL2 protein showed highest similarity to pectate lyases from the facultative plant-parasitic nematodes Bursaphelenchus mucronatus and B. xylophilus and the soil-inhabiting saprophytic Streptomyces and Frankia species (i.e. 40-42% identity and 58-60% similarity), whereas only a remote relatedness to the previously identified Gr-PEL1 was observed (i.e. 28% identity and 43% similarity). Transient expression of Gr-pel2 in leaves of Nicotiana benthamiana resulted in severe malformations of the infiltrated tissues, not relating to maceration and soft rot symptoms. Ca(2+) is known to be essential for pectate lyase activity, and the most likely calcium-binding site was identified in the Gr-PEL2 protein by combining homology modelling of the three-dimensional structure, site-directed mutagenesis and transient expression in leaves. A highly charged cleft in Gr-PEL2, which is likely to be involved in substrate binding and which is also significantly more hydrophobic in Gr-PEL1, was shown to be essential for protein activity. Our results underline the broad spectrum of pectate lyases and cell-wall-degrading enzymes necessary for successful parasitism by cyst nematodes.

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Section: Discussionmentioning

confidence: 99%

Structural and functional characterization of a novel, host penetration‐related pectate lyase from the potato cyst nematode Globodera rostochiensis

Kudla

Milac

Qin

et al. 2007

Molecular Plant Pathology

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“…Previous studies of plant-nematode interactions have focused largely on anatomical alterations induced by nematodes (Jones, 1981;Endo, 1986), and have tended to emphasize a role for xylem transport in the delivery of nutrients to the nematode feeding structures (Jones and Northcote, 1972;Sijmons et al, 1994). Bird and Loveys (1975) and McClure (1977) treated host plants of root-knot nematodes with 14C0, and were able to show that assimilates accumulated in feeding sites as well as in feeding nematodes.…”

Section: Discussionmentioning

confidence: 99%

“…The feeding structures induced by cyst nematodes have been the subject of numerous anatomical investigations (reviewed by Endo, 1986), but the functional transfer processes that occur between host and pathogen are still a matter of speculation (Sijmons et al, 1994). The cyst nem-atode Heterodera sckacktii belongs to a group of nematodes that induce syncytia, special feeding structures within the vascular cylinder of host roots (see Fig.…”

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confidence: 99%

Induction of Phloem Unloading in Arabidopsis thaliana Roots by the Parasitic Nematode Heterodera schachtii

et al. 1996

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Phloem unloading of both the fluorescent probe carboxyfluorescein (CF) and 14C-labeled solutes was induced in Arabidopsis thaliana 1. roots by the parasitic nematode Heterodera schachtii Schmidt. Confocal laser scanning microscopy demonstrated that anomalous unloading of CF from the sieve element companion cell complexes occurred specifically into the syncytium, the nematodeinduced feeding structure located within the stele of the root. From this syncytial complex of modified root cells, both fluorescent and radioactive labels were withdrawn by feeding nematodes. Movement of CF was unidirectional from the phloem to the syncytium. A range of low-molecular-weight fluorescent probes (including CF) microinjected into the syncytium stayed in this structure, demonstrating that it is symplastically isolated from the surrounding root tissue. l h e mechanism of unloading in this host-pathogen relationship therefore appears to be apoplastic. Our results provide unequivoca1 evidence that sedentary cyst-forming nematodes have direct access to phloem-derived solutes.

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“…Raat penetratian rnast frequently accurs in the zane af elangatian, behind the raat tip. Growth and differentiation of functional primary and secondary vascular tissues are inhibited (Endo, 1986). The feeding site of cyst nematodes is a multinucleate, metabolically active syncytium.…”

Section: Development and Maintenance Of The Feeding Sitementioning

confidence: 99%

“…Exudates that putatively originate fram the nematode's amphids produce an electran-dense 'feeding plug' in the cytoplasm araund the stylet of H. glycines at the site of stylet penetration into the syncytial cell wall . Parenchymatous tissue invades the region of the deteriorating syncytium in a wound-repair response, but the vascular system remains damaged and potentially impedes plant growth (Endo, 1986) (also see Chapter 9). The syncytium is formed by cell wall breakdown of neighbouring cells in the zone of differentiation of the raot.…”

Section: Development and Maintenance Of The Feeding Sitementioning

confidence: 99%

The Cyst Nematodes

Sharma¹

1998

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Histology and Ultrastructural Modification Induced By Cyst Nematodes

Cited by 19 publications

References 19 publications

Structural and functional characterization of a novel, host penetration‐related pectate lyase from the potato cyst nematode Globodera rostochiensis

Structural and functional characterization of a novel, host penetration‐related pectate lyase from the potato cyst nematode Globodera rostochiensis

Induction of Phloem Unloading in Arabidopsis thaliana Roots by the Parasitic Nematode Heterodera schachtii

The Cyst Nematodes

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