Microbial Ecology (GATE)

Epichloë resides in only grasses. It colonises the shoot portion of grasses. It provides several benefits to the host, including the production of different herbivore-deterring alkaloids, increased stress resistance and growth promotion.

Mucilages are the result of abrasive forces of the root against soil particulate matter that remove cells from the root cap. Mucilages are polar glycoproteins and exopolysaccharides.

Species of the hyphomycete genus (Arthrobotrys) produce constricting loops that quickly shut to grab nematodes or non-constricting loops or hyphal networks that entangle nematodes or sticky knobs that adhere to nematodes as they swim by.

Algae live as epibionts on many larger marine animals.

Archaea are very important for ammonification in rhizospheres. It is a process that includes transforming organically bound nitrogen from microbial or plant biomass to ammonia.

Pseudomonas syringae colonises phyllosphere (above-ground portions of plants). It lives in the leaf ecosystem as an epiphyte and a pathogen.

Pseudomonas putida is a beneficial bacterium that solubilises inorganic phosphorus from insoluble compounds.

Orchid seeds cannot germinate unless they have fungus that is attached. They depend on fungus to provide simple sugars.

The relationship between Laccaria Bicolor and plants can be described as mutualism. Laccaria Bicolor shows an excess of enzymes used in ammonia uptake and a lack of enzymes that would be needed to degrade plant wall material. Thus, the fungus provides nitrogen and does not cause any harm to the trees in return for glucose, which it gets from photosynthetic plants. 

Perennial legume nodules are long finger-like nodules, half an inch in diameter. They can be found on alfalfa and clover. These nodules grow mostly around the tap root and live for quite a long time.

Biodegradation step of carbon cycle would suffer in the absence of heterotrophs. They are important in the carbon chain for the processes of biodegradation and decomposition under aerobic and anaerobic conditions.

This is false. Phyllosphere can be considered a very hostile community because there is a limited availability of nutrients, strong sun irradiation and variation in water availability.

Trichodesmium belongs to the genus of filamentous cyanobacteria. It performs almost half of the nitrogen fixation in marine systems on a global scale.

The direct reduction of sulphate ions to hydrogen sulphide is effected in nature by specialised, strictly anaerobic bacterium of the genus Desulfotomaculum. These sulphate reducing bacteria (SRB) are heterotrophic organisms that utilise sulphate, thiosulphate, S2O3--, sulphite, SO3-- or other reducible sulphur-containing ions as terminal electron acceptors in their respiratory metabolism. In the process, these sulphur-containing ions are reduced to hydrogen sulphide.

Thiomicrospira produces sulphuric acid (hydrogen ions, H+ and sulphate ions, SO4--) as a metabolic product. This bacterium is involved in acid rock damage from pyritic and pyrrhotitic rocks under appropriate conditions.