Question

You are a mycologist and have been asked to identify a fungus causing an epidemic on an important agronomic crop. The plant sample you've been given displays the fungus in its sexual state. Based on symptoms, you suspect that it is an ascomycete, but there isn't a conspicuous ascocarp and you'll have to use a microscope. What structure should you look for to verify that it is indeed an ascomycete?

Answer 1

Answer:

an ascus with ascospores

Explanation:

The attached image shows the Sordaria fimicola ascus with ascospore.

An ascospore is a spore located in an ascus or that was formed within an ascus. This form of spore is particular to fungi categorised as ascomycetes (Ascomycota).

Ascospores are produces in ascus under optimal conditions. A single ascus will house eight ascospores. These eight spores are formed via meiosis coupled with a mitotic division.

Two meiotic divisions converts the initial diploid zygote nucleus to produce four haploid ones (the singilar initial diploid cell at the beginning possesses two whole sets of chromosomes). DNA duplication occurs ahead of meiosis to yield four sets. The nucleus wgich houses the four sets undergo division twice, to give a four new nuclei – each having a whole set of chromosomes. DNA duplication of the four new nuclei occurs coupled with mitosis division to produce an ascus with four pairs of spores. Then the ascospores are freed from ascus.