Look out! This little white flower can protect itself...in a major way. Alpine pennycress, a dandelion-looking plant found growing in the dirt next to former mines can absorb metal and use it to shield itself from disease, says a recent study in PLoS Pathogens. Why are we always so surprised to witness a seemingly primitive plant or animal adapting to things in post-industrial human societies? It's their world, too.
Anyway, back to the story--Zinc, nickel, or cadmium, if sucked up in high enough quantity and stored in Alpine pennycress leaves, can prevent growth of the pathogen Pseudomonas syringae. 50 different strains of Pseudomonas syringae thrive in the plant world, and each infect a different plant, leaving characteristic brown spots where the bacteria digests the leaf. Alpine pennycress has the (so far unique) ability to tuck away metals right where Pseudomonas infiltrates the plant: in the spaces in-between its leaf cells where water and solutes are transported across the leaf (called the apoplast.) Exactly how the metal stamps out the bacteria is unknown.
For this study, scientist injected an increasing amount of metal into the leaf apoplast to test if the metal affected host-pathogen rendezvous. It very much did: the more metal, the less Pseudomonas. Scientists also created Pseudomonas syringae mutants resistant to zinc, nickel, or cadmium which thrived on Alpine pennycress in comparison to regular Pseudomonas syringae. Cool double check.
So, if you're a human you might ask--what the h can we use this for?
A 2003 report mentions Alpine pennycress as a plant with bioremediation potential, along with about 400 other plants that remove heavy metals from soil. Can we use plants and microbes to clean up our messes? Yes. We can. Some scientist propose to use hydrocarbon-consuming microbes to clean up Deepwater Horizon in the gulf. In the future, could we simply plant sweet little white flowers everywhere to remove contaminates from drinking water around former mining sites? Maybe. But, let us not forget that we are adapting other species, and that has all kinds of consequences, too (I'm not trying to get all environmentalist, here, I'm just saying--take the science all the way.)
Armored flowers. Very 2011.
Fones H, Davis CA, Rico A, Fang F, Smith JA, & Preston GM (2010). Metal hyperaccumulation armors plants against disease. PLoS pathogens, 6 (9) PMID: 20838462
It's an idea, but doesn't those metals come back into the 'ecological circle' as the plant dies, drops its leaves, etc? Or are you saying that it somehow transforms it into something different?
ReplyDeleteYoron.
Good point. It seems like the metal WOULD seep back into the ground as soon as the plant dies. I imagine a bioremediation tactic might plant the flowers to suck up the metal, and then harvest them before they have a chance to die and redeposit the metal back into the soil. But, I'm not an expert, so I'm not 100% sure..
ReplyDeleteHi guys. Casey you are right that's how they do it. Some folks even mine metals this way.
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