Symbiosis
An intimate and long-lasting
association between
members of different
species.
Parasitism
One member benefits
the other is harmed.
Wheat Rust
Is a parasitic basidiomycete
that harms two hosts, wheat,
and one species of barberry.
Wheat Stage
Wheat Stage
The Red Stage – Uredinia with urediniospores
Wheat Stage
Urediniospores are borne on wheat. They are dikaryotic and go
on to infect wheat
Wheat Stage
The Black Stage Stage – Telia with teliospores
Teliospores
These are produced in the late summer. This is the overwintering stage.
Each spore consists of two dikaryotic cells.
Karyogamy occurs in each cell before they germinate
At germination meiosis occurs generating four haploid nuclei which are
divided between four cells in a four celled basidium
These basidiospores form in the spring.
They are haploid and monokaryotic.
They infect common barberry.
A lesion forms on the upper surface of the leaf called a spemagonium.
Hyphae called spermatia detach from this lesion and will float on dew to
other spermagonia..
Spermatia undergo plasmogamy with receptive hyphae forming the
dikaryon.
Dikaryotic hyphae grow through the leaf generating lesions on
the lower surface called aecia.
Aeciospores are dikaryotic and go on to infect wheat…...
Ergot fungus started as a parasite but now
represents a mutualistic partner with grains
such as rye.
It does not spoil all the grains….
But poisons herbivores, benefiting the plant….
Mutualism
Both members benefit.
Mutualism
All nitrogen fixing organisms are
bacteria. There are numerous examples
of mutualism between nitrogen fixing
bacteria and eukaryotes.
Azolla and Anabeana
This is a culturally and economically important plant used
as a green manure crop in Southeast Asia
Rhizobium and legume plants.
Rhizobium induce the clover to generate nodules.
These provide conditions of constant but low
oxygen levels necessary for nitrogen fixation.
This is mediated by the production of a form of
hemoglobin. The plant produces the protein,
the bacterium the heme…..
Mutualism
Mycorrhizae.
Endomycorrhizae of
Ectomycorrhizae of Pine.
Mutualism
Lichens.
Mutualism
Bullhorn Acacea and Ants.
Mutualism
Paramecium and Chlorella.
Mutualism
Anemone and Dinoflagellates
(Zooxanthellae)
Mutualism
Euglena gained photosynthesis
through endosymbiosis with a green
alga.
Mutualism
Mitochondria arose through
endosymbiosis of aerobic bacteria.
Cheek cells stained for mitochondia.
Cheek cells stained for mitochondia.