The promoter of the Arabidopsis thaliana Cel1 endo‐1,4‐β glucanase gene is differentially expressed in plant feeding cells induced by root‐knot and cyst nematodes

Abstract

SUMMARY Transgenic tobacco and Arabidopsis thaliana carrying the Arabidopsis endo-1,4-beta-glucanase (EC 3.2.1.4) Cel1 promoter fused to the beta-glucuronidase (GUS) reporter gene were infected with the root-knot nematode, Meloidogyne incognita, and either the tobacco cyst nematode, Globodera tabacum (tobacco), or beet cyst nematode, Heterodera schachtii (Arabidopsis). Cel1-driven GUS expression was detected in cell elongation zones of noninfected plants and within feeding sites (giant-cells) induced in roots of both plant hosts by M. incognita. The first detectable signs of Cel1 expression within developing giant-cells occurred at the onset of giant-cell formation and continued throughout the M. incognita life cycle. UidA (Gus) transcripts were detectable within giant-cells induced in tobacco roots at 11-13 days postinoculation with M. incognita as determined by in situ mRNA hybridization. By contrast, expression of the Cel1 promoter was not detected within developing syncytia induced in tobacco or Arabidopsis roots by G. tabacum and H. schachtii, respectively, at any time point. The results demonstrate specific regulation of cell wall-degrading enzymes that may be required for cell wall modifications during feeding cell formation by sedentary endoparasitic nematodes. Differential expression of Cel1 by cyst and root-knot nematodes further supports underlying mechanistic differences in giant-cell and syncytium formation.

Arabidopsis endo‐1,4‐β‐glucanases are involved in the formation of root syncytia induced by Heterodera schachtii

“…With promoter:GUS studies it was also found to be upregulated in giant cells induced by root-knot nematodes, but not in syncytia of cyst nematodes (Mitchum et al, 2004). In our Genechip analysis, however, we found it to be moderately upregulated at 5 dai in syncytia, whereas it was not detectable by any of the other methods.…”

“…An analysis in Arabidopsis revealed AtCel1 to be upregulated upon infection with the root-knot nematode M. incognita. However, infection with G. tabacum or H. schachtii did not lead to its expression (Mitchum et al, 2004;Sukno et al, 2006). Whereas these studies were focused on single genes that were selected on the basis of single observations, our work monitors and analyses the expression of the entire endo-1,4-b-glucanase gene family in the roots of Arabidopsis upon infection with the cyst nematode H. schachtii.…”

“…Previously published reports dealing with the involvement of endo-1,4-b-glucanases in the development of syncytia and giant cells were restricted to expression and localization studies of single upregulated genes (Goellner et al, 2001;Mitchum et al, 2004;Sukno et al, 2006). However, these studies did not provide evidence that these genes are functional in the formation and maintenance of feeding sites.…”

The Novel Cyst Nematode Effector Protein 19C07 Interacts with the Arabidopsis Auxin Influx Transporter LAX3 to Control Feeding Site Development

“…The soybean cyst nematode (Heterodera glycines) was propagated on Glycine max roots. Preparation and hatching of nematode eggs were performed as described (de Boer et al, 1999;Goellner et al, 2001;Mitchum et al, 2004). After 48 h of hatching, second-stage preparasitic juveniles were collected by low-speed centrifugation (8,000 rpm) in a tabletop centrifuge and surface sterilized for 10 min in a 0.004% mercuric chloride, 0.002% sodium azide, and 0.001% Triton X-100 solution, followed by five washes in sterile distilled water.…”

Root Infection and Systemic Colonization of Maize byColletotrichum graminicola

“…5G were prepared using previously described methods (37). Briefly, the tissues were fixed in Methacarn (55) for 24 h at 4°C, dehydrated in a graded ethanol series, and embedded in paraffin.…”