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(Skarbilovich, 1959) Behrens, 1975
Tylenchus (Heterodera) (Schmidt, 1871)
Heterodera (Heterodera) (Schmidt, 1871)
and Krall', 1978)
(Shagalina and Krall', 1978)
Refer to Subfamily Diagnostics (Heteroderinae)
for taxonomic history and distinctions among related genera.
As of 2013, the genus Globodera consists of 10 species.
Slide show on
Globodera and Heterodera spp.
Most characters of G. rostochiensis do not differ significantly from
those of G. pallida. However, the adult females of G. pallida are
white in contrast to the yellow color of G. rostochiensis. In addition,
the juveniles of G. pallida are larger, and the stylet and tail are
longer (Stone, 1973b). Stylet knobs are pointed anteriorly in G. pallida and
rounded in G. rostochiensis. Adult females of G. pallida possess
longer stylets than those of G. rostochiensis and have a shorter anal-vulval
distance. Adult males of G. pallida have a shorter stylet width and the
dorsal esophageal gland orifice is closer to the stylet knobs than in G.
rostochiensis (Stone, 1973b).
Female: body forms a cyst.
Prominent cephalic framework and stylet.
Anterior neck-like region; swollen body shape - lemon, round, or
pyroid shape (about 0.5-0.6 mm diam).
Weak cephalic framework; moderate stylet with small rounded knobs.
enlarged and fills neck region.
coiled or reflexed.
Vulva subterminal; anus terminal.
Posterior region important taxonomically:
Pre-parasitic stage: vermiform J2, 300-500 µm.
Heavily sclerotized head framework; head offset.
Stylet prominent with anteriorly-directed knobs.
Ventro-lateral overlap of esophageal glands over intestine.
Stylet weak, sometimes not visible in 3rd and 4th
Developing gonads visible.
[Ref: H. Ferris.]
Sclerotized cephalic framework, rounded head cap.
Strong stylet; knobs project forward.
Esophagus Tylenchid, overlaps ventro-laterally.
Reproductive system monorchic.
Tail bluntly rounded.
Phylogenetic analyses based on DNA sequence data suggest two major
Globodera spp.clades (Subbotin et al., 2011). One clade consists of
the Globodera spp. that are parasites of plants in the Solanaceae..
They include the G. tabacum group from North America and the potato
cyst nematodes (G. rostochiensis and
G. pallida from South America. The other
clade comprises Globodera parsites of non-solanaceous plants. They
include a group of Globodera spp. that are parasites of Asteraceae and
another group from the Western Cape Province of South Africa.(Knoetze et al.,
Stone (1979) suggested that the genus Globodera might have
originated in the part of Gondwanaland that became South America. Recent
data supports a theory that divergence of the two main Globodera
groups may have occurred subsequent to the separation of Africa and South
America (Subbotin et al., 2011; Knoetze et al., 2017).
Juveniles enter root by direct penetration of cells.
In the photograph, exposure
of an infective potato cyst
rostochiensis) nematode juvenile (J2) to potato root diffusate
triggered the secretion of subventral gland proteins through the stylet.
The secretions were not stimulated in water. Secretions were stained with
Coomassie Brilliant Blue G-250 (Smant et al. 1997).
The syncytium is stimulated in a cortical or endodermal cell. The syncytium
becomes multinucleate after 24 hours as adjacent cells merge. Cell wall
dissolution is through a combination of physical stress (nematode head movement)
and chemical action. Syncytia associated with developing males are usually
smaller than those associated with females.
Large sectors of the developing root, including areas that would have become
vascular tissue are transfomed into syncytia. Syncytia have many plastids,
mitochondria, ribosomes, increased rough endoplasmic reticulum and enlarged
lobed nuclei. There appears to be no synthesis of DNA and nuclear division
probably does not occur.
Cell wall protruberances increase the surface area of the cell membrane for
flow of solutes from the xylem to the syncytium - the transfer cell
configuration (Endo, 1975).
Several forms of delayed hatch and diapause are exhibited in the
hatch occurs in response to host root exudates.
Species vary in degree of response to hatching factors:
a) Very sensitive - hatch in
water only 5% of that in host root
G. rostochiensis, H. carotae, H. cruciferae,
b) Intermediate - hatch in
water 10-50% of that in diffusate.
H. schachtii, H. trifolii, H. galeopsidis.
c) Insensitive - apparently not
stimulated by diffusate.
H. goettingiana, H. avenae, H. glycines. H. avenae
requires a chill
period to break diapause.
Hatching factor for G. rostochiensis thought to be a monobasic acid with
molecular weight about 220 and possible formula C11H16O4. The factor breaks down
rapidly in soil (results of 30 years research!). This is an area of
considerable research activity because of the potential for reducing survival.
Artificial hatching agents include Anhydrotetronic acid for G. rostochiensis,
Aminoacridine (Rivanol) and ZnCl for H. schachtii.
Ecological factors also influence hatch: temperature, moisture, aeration,
osmotic potential, pH, etc.
J2 enters near root tip and takes position in cortex with head near
vascular cylinder. Moves intra- and intercellularly towards vascular
During development, female breaks through cortex to surface so that
most of the body of adult female remains outside root.
Sugarbeet cyst nematode (H. schachtii) molts at 6, 12, and 15
days after entering root; matures in 19 days at 25 C.
Males are needed for reproduction in most species.
Eggs are retained in cysts, but some are deposited in egg masses in
Distended uterus enlarges to fill body; eggs are packed in mucoid mass.
Cysts undergo a color change as they mature - from white to brown (through
gold in G. rostochiensis) - due to action of polyphenol oxidase on
polyphenols in the cyst wall. The wall remains permeable to chemicals and
Cyst drops-off of root when dead; mucoid packing disappears.
G. rostochiensis - 1 generation per year in Europe.
- about 2 generations per year in Europe.
about 3 generations per year in northern California.
about 5 generations per year in the Imperial Valley.
H. glycines - about 5 generations per
year in North Carolina.
Little mechanical injury due to the parasitism, body of female on outside of
the root and no cell division stimulated.
Branch rootlets may be stimulated near the point of infection.
General debilitation and reduction in efficiency of the root system.
Chlorosis, stunted growth, wilted plants.
Management strategies vary with species and biology.
Possibilities include prevention, crop rotation, soil fumigation,
use of resistant
varieties, and use of clean seed sources.
Management of these genera is usually difficult due to prolonged
Behrens, E. (1975) Globodera Skarbilovic, 1959, eine selbstindige Gattung in
der Unterfamilie Heteroderinae Skarbilovic, 1947 (Nematoda: Heteroderidae).
Vortragstagung zuaktuellen Problemen der Phytonematologie am 29/5/1975 in
Rostock. Manuskriptdruck der Vortrage. Rostock, 1975, pp.12-26.
Smant, G., A. Goverse, J.P.W.G. Stokkermans, J.M. De Boer, H. (Rikus) Pomp,
J.F. Zilverentant, H.A. Overmars, J. Helder, A. Schots and J. Bakker. 1997.
Potato Root Diffusate-Induced Secretion of Soluble, Basic Proteins Originating
from the Subventral Esophageal Glands of Potato Cyst Nematodes. Phytopathology
Stone, A.R. 1973b. "Heterodera pallida." Commonwealth
Institute of Helminthology Descriptions of Plant-Parasitic Nematodes, Set 2,
Stone, A.R. (1979). Co-evolution of nematodes and plants. Symbolae
Botanicae Uppsala 22, 46-61. 1997
Subbotin, S.A., Cid Del Prado Vera, I., Mundo-Ocampo, M. & Baldwin, J.G.
(2011). Identification, phylogeny and phylogeography of circumfenestrate
cyst nematodes (Nematoda: Heteroderidae) as inferred from analysis of
ITS-rDNA. Nematology 13, 805-824. DOI: 10.1163/138855410x552661