botanyspeaking

Geminivirus causes tobacco flower to twist.

In microscopy, science plants on December 8, 2011 at 2:33 pm

Epidermal peel of Tobacco Flower, note protruding trichome (hair). Nuclei can be seen in some cells.

Geminivirus infection causes flowers to twist and curl. Individual cells can be seen twisted.

It’s a cancer of plants caused by a virus called a geminivirus. It causes cells that would normally be happily expanding to abandon that routine and go back into the cell division cycle. This then causes all sorts of mixed signals to proliferate and leaves begin to yellow, curl, twist. They are no longer functional for their purpose of providing sugars. The virus has taken over. The plant cell forgets its purpose and becomes a slave to the virus; it multiplies the viral DNA, makes viral proteins, assembles virions. Not a good day for the plant. Sometimes they die. They are not useful for human consumption because they lack energy to make fruits or leaves.

But the flowers of Nicotiana benthamiana, a wild relative of tobacco, continue to form. But instead of nice strait tubular flowers they twist and shrink. I took a notion to examine their cells. A simple epidermal peel is made like peeling the skin of an onion. You did it if you took biology. It’s a great way to get a single layer of cells for visualizing under a microscope. Well, peeling the flower petal showed that the twisted flower had twisted cells. The twisted cells left empty spaces. Click the images to see the nuclei and greater detail. More about geminiviruses later. If I can only find my pictures of infected plants!

© 2011 Sharon Settlage

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  1. Super Interesting theme. Something we are not used to get references of. Do you know what makes them twist? is that beneficial for the virus or we can’t tell by now? Do you have any ideas?
    That really is a great experiment!

    I have a site of microscope for kids anbd I think I’ll recommend that experiment!

  2. Hi Spencer,
    i think the twisting is an accident of nature that results from having the plant cell being reprogrammed to turn on its DNA replication machinery.
    If you haven’t already, I’d recommend doing an onion peel to start. It’s easy to get a single layer of cells from one of the inside sections. Nuclei are readily visible as the section is translucent.
    thanks for your comment!
    Sharon

  3. Great picture! I was looking online for a comparison photo of plant cells infected with Gemini virus. I’m an hobby gardener with some biology background. I noticed the plants I suspected of having the virus had abnormal cells that were twisted. I’m sending the sample to the U of M to confirm it but after seeing your picture, I’m sure now that this is the culprit.

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