Ultrastructure of feeding sites of the cyst nematode Heterodera schachtii Schmidt in roots of susceptible and resistant Raphanus sativus L. var. oleiformis Pers. cultivars

Soybean cyst nematode (SCN) resistance in soybean is a complex oligogenic trait. One of the most important nematode resistance genes, rhg1, has been mapped to a distal region of molecular linkage group G in soybean. A simplified genetic system to identify soybean genes with modified expression in response to SCN led to the identification of several genes within the nematode feeding sites. The genes were mapped to reveal their linkage relationship to known QTLs associated with soybean cyst nematode (SCN) resistance. One candidate, a phosphoribosyl formyl glycinamidine (FGAM) synthase (EC 6.3.5.3) gene, mapped to the same genomic interval as the major SCN resistance gene rhg1 within linkage group G. Isolation of FGAM synthase from a soybean bacterial artificial chromosome (BAC) library revealed two highly homologous paralogs. The genes appeared to be well conserved between bacteria and humans. Promoter analysis of the two soybean homologs was carried out with the Arabidopsis thaliana – Heterodera schachtii system to investigate gene response to nematode feeding. The two promoters and their derived deletion constructions effected green fluorescent protein (GFP) expression within nematode feeding sites. The 1.0-kb promoter sequence immediately adjacent to the translation start site was sufficient to direct expression of GFP within syncytia. A wound-inducible element and a floral organ expression sequence were also identified within these promoters. Although a nematode-responsive element could not be identified, the observed expression of GFP within feeding sites supports the hypothesis that plant gene expression is redirected within feeding sites to benefit the parasite.Key words: FGAM synthase, promoter analysis, syncytium, Heterodera schachtii, soybean cyst nematode.

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Influence of the cyst nematode Heterodera schachtii on relative changes in the pattern of free amino acids at feeding sites

Physiological Plant Pathology ◽

10.1016/0048-4059(82)90076-5 ◽

1982 ◽

Vol 21 (3) ◽

pp. 425-436 ◽

Cited By ~ 11

Author(s):

H.J. Krauthausen ◽

U. Wyss

Keyword(s):

Amino Acids ◽

Free Amino Acids ◽

Free Amino ◽

Cyst Nematode ◽

Heterodera Schachtii ◽

Feeding Sites

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Structure of syncytia induced by Heterodera schachtii Schmidt in roots of susceptible and resistant radish (Raphanus sativus L., var. oleiformis)

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1998.024 ◽

2014 ◽

Vol 67 (3-4) ◽

pp. 207-216 ◽

Cited By ~ 8

Author(s):

Grażyna Grymaszewska ◽

Władysław Golinowski

Keyword(s):

Endoplasmic Reticulum ◽

Cell Wall ◽

Raphanus Sativus ◽

Smooth Endoplasmic Reticulum ◽

Lateral Roots ◽

Heterodera Schachtii ◽

Wall Ingrowths ◽

Raphanus Sativus L ◽

Rough Er ◽

Cell Wall Ingrowths

The structure of syncytia induced by <i>Heterodera schachtii</i> Schmidt in roots of susceptible <i>Raphanus sativus</i> L. cv. "Siletina" and resistant radish cv. "Pegletta" was investigated. In the radish cultivar "Siletina" the syncytia most often appeared in the elongation zone of lateral roots. They were initiated in the procambium and pericycle but also included the parenchyma cells of vascular cylinder. In the susceptible cultivar "Siletina" the cells forming the female's syncytia were subject to hypertrophy. Their cytoplasmic density increased. The cytoplasm contained numerous organella. The proliferation of the smooth endoplasmic reticulum took place. Branched cell wall ingrowths were formed next to the vessels. In the male's syncytia the cells were only slightly increased. Their protoplasts contained few organelles. The cell wall ingrowths were poorly developed. In the syncytia of the resistant cultivar "Pegletta" there was only a slight increase of the cell volume. A well developed system of rough endoplasmic reticulum was observed in the protoplast. Distended ER cisterns contained fine fibrillar material. Material of similar structure also appeared in numerous small vacuoles. In resistant plants only some, not numerous, syncytia spreading in procambium fully developed and functioned long enough for the parasite females to mature. At an advanced stage of infection a well developed system of a rough ER was observed also in those syncytia and numerous vacuoles appeared.

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