Lab 4 update

Ustilago maydis

Using a pair of scissors in my lab supply kit, on October 9, 2012, I excised a leaf from my corn seedling showing symptoms of infection from inoculation with Ustilago maydis on September 26, 2012. I placed the leaf in a Petri dish and covered it with a 2:1 ethanol:acetic acid solution to remove the chlorophyll. Approximately 30 hours later, I drained the 2:1 ethanol:acetic acid solution from the plate and triple rinsed the leaf with non-sterile deionized water. I patted the leaf dry with a paper towel and then covered it with 0.1% trypan blue in lactophenol to stain any fungal structures that may be present. Approximately two hours later I rinsed the leaf with non-sterile deionized water, patted it dry with a paper towel and then mounted it in lactophenol on a microscope slide for viewing using an Olympus CX31 compound microscope. I took photographs through the eyepiece of the microscope using a Canon PowerShot SD550 digital camera. Photographs were cropped and enlarged on a computer to show detail.

Conjugation of sporidia to produce dikaryotic hyphae that are necessary to infect the corn seedling.

Dikaryotic hyphae that appear to be invading the corn seedling via the stomata.

A budding sporidium.

Conjugating sporidia.

Yeast-like sporidia.