Week 5
Topic : Microbial Interaction

This week, I learned about microbial interactions which may be parasitism, one organism benefits at the cost of another; mutualism, both organisms benefit; commensalism, one organism benefits at no cost or benefit to the other; or amensalism, one species is inhibited or completely obliterated and one is unaffected. Mycorrhizae, protozoan-termite relationship and zooxanthellae are examples of the mutualistic interaction.

Mycorrhizae can be described as a symbiotic relationship between a fungus and a plant. Due to the fact that this is a symbiotic relationship, both the fungus and the plant benefit from this interaction. The mycorrhizae aid the plant with growth, yield, improved fitness, increase the root absorption area of nutrients, while the fungus receives carbon from the associated plant. Endomycorrhizae and ectomycorrhizae are the two main types of mycorrhizae that produce the same overall results, but with different fungal characteristics.

In protozoa-termite relationship, the termite provide food for protozoa while protozoa digests cellulose in wood particles and provide nutrients for termite. The symbioses in the termite gut are often beneficial to both partners and so are called a mutualistic relationship. 

Species within Aphidoidea have established mutualistic relationships with the obligate intracellular endosymbiont Buchnera aphidicola to overcome nutritional deficiency of such unbalanced diets. Buchnera are grown within specialized cells known as bacteriocytes. They produce nutrients (essential amino acids) that are not synthesized by insects or obtained sufficiently from plant saps. In return, aphids provide Buchnera with other nutrients required to survive. 

Pea aphid (Acyrthosiphon pisum) living with their endosymbiont Buchnera aphidicola. 

This topic is very interesting as I get to know the various interactions between two or more different species of organisms. Who would have thought that the interaction of microbes not only cause one organism benefits at the cost of another but can benefit both organism or one organism benefits at no cost or benefit to the other.

During the class on Thursday (26 March 2015), we were given a task to find materials that related to the topic microbial interactions. Every person is required to find and share with class members through padlet.

This is an article that I found about the role of bacteria and mycorrhiza in plant sulfur supply.