• Julie G - Microbigal!

Witches Warts on Trees? - Blemishes of evil or beautiful and useful art by Microbes!


Happiest of Halloween you scary tiny microbes! Halloween is the one time of year that imperfection is celebrated and emulated! Witch’s warts, deformities, blemishes, and oddities of all sorts are Halloween traditions - the scarier and grosser the better! The Giants spend gobs of money on makeup and costumes to give themselves warts, scars and deformities that they would normally be revolted by! In nature though, lots of things grow where they aren't expected, and to some they can be considered an abomination! But perhaps there's more to it, perhaps what some consider to be an ugly wart is actually a useful thing that can be beautiful!


Ms. Myco - you look so scary!



And what's that on your nose?!?




Halloween is the best isn't it! I've got my witch's costume on, complete with nose with a wart!


Burl on a tree in the White Mountain National Forest in New Hampshire.
Tree Wart?

Have you ever seen a tree with a giant tumor-like deformity growing out like a wart? It usually appears as a large circular lumpy mass on the trunk. This is usually the product of microbes called Agrobacterium tumefaciens. There is little to suggest that these are actually harmful to the trees. It's like a wart on a tree, an unusual growth that is created by guess what? Microbes, of course!




Microbes In Nature



Tree burl in the White Mountain National Forest in New Hampshire

In nature, Agrobacterium tumefaciens causes strange deformities on tree trunks and roots that grow out in all directions. The condition is called crown gall. It begins when A. tumefaciens injects a piece of its DNA into the host and the host incorporates this foreign DNA with its own.


The foreign DNA forces the plant to produce these tumor or gall deformities that secrete opines. What’s the benefit for the microbe? Opines are like candy to A. tumefaciens; it can feast on them for days.


Tree burl in the White Mountain National Forest in New Hampshire
Check this one out - Front....

Tree burl in the White Mountain National Forest in New Hampshire
and back! How cool is that?!



A. tumefaciens: Scientific Tool

Where does this microbe come from? It occurs naturally in the soil. In this way it

possess a split personality, one to live freely in the soil and one to live parasiti


cally within the plant. Manipulating the host for its own survival.

Interestingly, this parasitic bacteria that causes these deformities on a wide variety of plants is actually one of scientists’ greatest biotechnological tools. Because of its ability to inject DNA straight into the host cells, it is used in a biotechnology to make genetically modified plants.


The ability to form a tumor in a plant is not what scientists are after however. What they are able to do is to manipulate these microbial mechanisms to genetically modify plants for the benefit of humanity. Scientists are able to remove the genes that cause crown gall and insert genes more to their liking, such as disease-resistant genes in their place.

This engineered A. tumefaciens is then placed into the plant where it injects its DNA into the young host and the host will incorporate this DNA into its own. If the plant incorporates these genes successfully, it will now be resistant to a particular disease.


This has a whole slew of applications; plants which are resistant to disease will require less pesticides or insecticides, making them better for you and the planet.


In addition, with fewer diseased plants, a farmer’s crop can be more bountiful, producing more food and less wasted crop helping to feed the farmer, their family, and the planet! I’ll bet there’s not as much use for that wart with the hair growing out of a witch’s nose!


A. tumefaciens: Microbial Artist!

These unique and wonderful tree warts, often called burls, can also be carved into works of art! These growths are highly sought out by wood turners that turn these 'warts' into bowls, wall art, figurines, sculptures, tables, statues and many other beautiful things.



Isn't that amazing? What some see as a blemish can be turned into a thing of beauty or used in science to increase crops. As a matter of fact, this classroom we're in right now is actually a burl in the roots of a great tree! So look a little closer at the things you encounter, warts and all, wherever they may show up, and perhaps you will find something more than a Halloween costume idea!




Microbes learning to be Microbes at Halloween!


Note: Burls should never be removed from a living tree - if you remove it, the scar it leaves will most likely kill the tree - and we don't want that!

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