1. The document discusses various types of interactions between nematodes and bacteria, including synergistic, antagonistic, additive, neutral, amensalism, protocooperation, mutualism, and parasitism. 2. Key examples of nematode-bacteria interactions discussed include entomopathogenic nematodes associated with Xenorhabdus bacteria, the Laxus oneistus marine nematode and its thiotrophic surface colonizing bacteria, and filarial nematodes harboring intracellular Wolbachia symbionts. 3. Nematode-bacteria interactions can result in both plant disease complexes through obligatory or fortuitous relationships, or provide advantages such as producing useful metabolites, restoring

1. ALIGARH MUSLIM UNIVERSITY
FACULTY OF LIFE SCINCES
DEPARTMENT OF BOTANY
NEMATODE BACTERIAL INTERACTION
MOHD SALIM
18BTM-028
Dept. of Botany
AMU .ALIGARH

2. CONTENTS
• What is interaction
• Types of interaction
• Nematode bacterial interaction
• Model system of nematode bacterium symbiosis
• Types of interaction between nematode and bacteria
• Nematode bacterial disease interaction
• Conclusion
• References

4. TYPES OF INTERACTION
SYNERGISTIC INTERACTION
ANTAGONISTIC INTERACTION
ADDITIVE INTERACTION

5. • Dickinson (1979) first introduced the word synergism in plant
pathology.
• In this interaction bio predisposition is involved the damages
caused by the two pathogens, together is greater than the sum
of the damages caused by both the pathogens separately.
Leads to development of disease complexes are such as:
• wilt& root rot disease complexs

6. ANTAGONISTIC INTERACTION
• In general, the effect of two organisms are less than the amount
of the effect of two species, taken independently of one another.
• Various mechanisms may be involved depending on the
engaged organisms:
• 1) Competition for root space
• 2) Nematodes feed on bacteria& Bacteria produces metabolites
toxic to nematodes.

7. ADDITIVE INTERACTION
• The effect of the two species is equal to the amount of the effect
taken separately from the two species.

8. Nematode bacterial Interaction
• Different types of interactions between nematodes and
bacteria may exist in nature in relation to benefit or harm
given or received.
• The most important type of interaction is that in which, the
bacteria are able to infect a host plant.

9. Model systems of nematode-bacterium symbiosis
• Nematodes and their bacterial associates exist in marine,
freshwater, soil and plant or animal host environments.
• The most thoroughly studied of the
nematodes, is a terrestrial nematode,
whose relationships with bacteria
are predatory, defensive and possibly
commensal.

10. • Emphasize three such associations are here:
1. Terrestrial entomopathogenic nematodes associated with
Xenorhabdus.
2. Photorhabdus bacteria and Laxus oneistus marine nematodes
with thiotrophic surface-colonizing bacteria.
3. Parasitic filarial nematodes colonized by intracellular
Wolbachia symbionts.

11. 1. Entomopathogenic nematodes (EPNs) and bacteria
Two genera of nematodes:
1. Steinernema
2. Heterorhabditis, have evolved symbiotic associations with
gammaproteobacteria, Xenorhabdus and Photorhabdus
There are three species recognized within the Photorhabdus genus:
1. P. temperate
2. P. luminescens
3. P. asymbiotica.

12. 2. Laxus oneistus symbiosis
• Stilbonematids occur in marine sand and establish
ectosymbioses with thiotrophic gammaproteobacteria.
• L. oneistus ectosymbiont
cells are rod shaped and
aligned perpendicularly to the
nematode surface, forming an
epithelium-like monolayer.

13. 3. Filaria nematode-Wolbachia symbiosis
• Wolbachia are alphaproteo bacteria belonging to the order
Rickettsiales and closely related to Anaplasma , Ehrlichia and
Rickettsia.
• Wolbachia are perhaps the most abundant of all intracellular
bacteria, being found in filarial nematodes and arthropods, with
around 70% of insects species colonized.

14. Nematodes can interact with Bacteria in several ways

15. 1. Neutralism
The neutral relationship between nematodes and bacteria is the
predominant relation that occurs in soils from a numerical point
of view.

16. 2. Amensalism
• Soil bacteria have been likened by some investigators to
biochemical factor is that pump out numerous metabolic
products during the process of decomposing plant and animal
residues.

17. 3. Protocooperation
• Protocooperation exists where both populations benefit from
the association which is not obligatory.
• The two associates will survive and reproduce without the
presence of the other:"Ear-cockle" disease of wheat and
"cauliflower" disease of strawberry

18. 4. Mutualism
• This is the relationship of Neoaplectana carpocapsae to the
bacterium, Achro- mobacter nematophilus.
• The infective-stage juveniles of the nematode were able to
penetrate and kill the insect host without the presence of A.
nematophilus or any other bacterium.

19. 5. Parasitism
• The interaction, parasitism, will emphasize the bacterium
Pasteuria penetrans. Because of the bacterium's unusual
morphology, this in- teraction may seem atypical.
• It is currently the best-documented example of a bacterial
parasite of nematodes.

20. Nematode bacterial disease interactions
Plant disease complexes involving nematodes grouped into two
kinds:
1. Obligatory relationships
2. Fortuitous relationships
• Obligatory relationship: one member is completely dependent
on another or directly influenced by it. The expression of
plant disease symptoms occur only when the nematode and
the bacterium are present together.
• Fortuitous relationship: each member acts independently and
is not directly influenced by the other member. In this type of
relationship the presence of the nematode is not required for
the expression of disease symptoms.

21. Nematode bacterial disease interactions

23. Adv. and Dis adv. Between nematode bacterial interaction
Advantages:
• Production of useful
metabolites for host.
• Restoring diversity.
• Improved metabolic
control.
Dis advantages:
• Introducing non-indigenous
bacterial spp.
• Promoting bacterial
pathogenic spp.
• Decreasing nutrients
utilization by the host.

24. CONCLUSION
Interactions between nematodes and bacteria is scanty.
Considering the economic importance of plant-parasitic
nematodes as disease agents, and as significant components
of the ecosystem of the earth.

25. References
• Barker, K.R., Lehman, P.S. and Huisingh, D., 1971. Influence of nitrogen and Rhizobiumjapon-
icum on the activity of Heterodera glycines. Nematologica.
• Mankau, R., 1972. Utilization of parasites and predators in nematode pest management ecology.
Proceedings Tall Timbers Conference on Ecological Animal Control by Habitat Management.
• Starr, M.P., 1975. A generalized scheme for classifying organismic associations. Syrup. Soc. Exp.
Biol.
• Thorne, G., 1940. Duboscqia penetrans n. sp. (Sporozoa: Microsporidia, Nosematidae), a parasite
of the nematode Pratylenchus pratensis (de Man) Filipjev. Proc. Helminthol., Soc. Wash.
• Walker, J.T., 1969. Pratylenchus penetrans (Cobb) populations as influenced by microorganisms
and soil amendments. J. Nematol.
• Williams, J.R., 1960. Studies on the nematode soil fauna of sugarcane fields in Mauritius. 5. Notes
upon a parasite of root-knot nematodes. Nematologica.
• Jorgenson, E.e. (1970) Antagonistic interaction of Heterodera schachtii Schmidt and Fusarium
oxysporum (Wool.) on sugarbeets. Journal of Nematology.
• Go ¨ttfert, M., 1993. Regulation and function of rhizobial nodulation genes. FEMS Microbiol.
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