nygreenguy
04-17-2009, 01:08 AM
A carotenoid-derived hormonal signal that inhibits shoot branching in plants has long escaped identification. Strigolactones
are compounds thought to be derived from carotenoids and are known to trigger the germination of parasitic plant seeds and
stimulate symbiotic fungi. Here we present evidence that carotenoid cleavage dioxygenase 8 shoot branching mutants of pea
are strigolactone deficient and that strigolactone application restores the wild-type branching phenotype to ccd8 mutants.
Moreover, we show that other branching mutants previously characterized as lacking a response to the branching inhibition
signal also lack strigolactone response, and are not deficient in strigolactones. These responses are conserved in Arabidopsis.
In agreement with the expected properties of the hormonal signal, exogenous strigolactone can be transported in shoots and
act at low concentrations. We suggest that endogenous strigolactones or related compounds inhibit shoot branching in
plants. Furthermore, ccd8 mutants demonstrate the diverse effects of strigolactones in shoot branching, mycorrhizal
symbiosis and parasitic weed interaction.
Vol 455| 11 September 2008| doi:10.1038/nature07271
I just read this article not too long ago and all the talk about evolution here reminded me of it!
Here's why things like this is cool. We have carotenoids, they make up many parts of plants photosynthetic pathway. Now, if we take on of there, and just break on bond, we now have a hormone. Now if we just break off one more thing, we have another hormone. If we add a carboxyl group, we have another hormone. What we have are the very specific chemicals which, when slightly modified, suddenly become a totally new novel chemical. We also see the same thing with many unit repeats. We have one chemical which is a 5 carbon compound. We add on another to get a 10 carbon and we got a new novel chemical. Add another 5 carbon or another 10 carbon and we have a new chemical.
Many people claim how these super specific hormones are "irreducibly" complex but any chemist will tell you its simply in the nature of molecules to undergo these changes! Its absolutely fascinating how nature is so efficient and how everything is simply built on what came before.
The rest of the paper has some neat stuff about how this hormone acts in various plants. (it acts as a seed germinator in parasitic plants, allows mychorizae to recognize the plant and facilitates bud growth) So, if anyone wants I can post more, I just though this was interesting.
are compounds thought to be derived from carotenoids and are known to trigger the germination of parasitic plant seeds and
stimulate symbiotic fungi. Here we present evidence that carotenoid cleavage dioxygenase 8 shoot branching mutants of pea
are strigolactone deficient and that strigolactone application restores the wild-type branching phenotype to ccd8 mutants.
Moreover, we show that other branching mutants previously characterized as lacking a response to the branching inhibition
signal also lack strigolactone response, and are not deficient in strigolactones. These responses are conserved in Arabidopsis.
In agreement with the expected properties of the hormonal signal, exogenous strigolactone can be transported in shoots and
act at low concentrations. We suggest that endogenous strigolactones or related compounds inhibit shoot branching in
plants. Furthermore, ccd8 mutants demonstrate the diverse effects of strigolactones in shoot branching, mycorrhizal
symbiosis and parasitic weed interaction.
Vol 455| 11 September 2008| doi:10.1038/nature07271
I just read this article not too long ago and all the talk about evolution here reminded me of it!
Here's why things like this is cool. We have carotenoids, they make up many parts of plants photosynthetic pathway. Now, if we take on of there, and just break on bond, we now have a hormone. Now if we just break off one more thing, we have another hormone. If we add a carboxyl group, we have another hormone. What we have are the very specific chemicals which, when slightly modified, suddenly become a totally new novel chemical. We also see the same thing with many unit repeats. We have one chemical which is a 5 carbon compound. We add on another to get a 10 carbon and we got a new novel chemical. Add another 5 carbon or another 10 carbon and we have a new chemical.
Many people claim how these super specific hormones are "irreducibly" complex but any chemist will tell you its simply in the nature of molecules to undergo these changes! Its absolutely fascinating how nature is so efficient and how everything is simply built on what came before.
The rest of the paper has some neat stuff about how this hormone acts in various plants. (it acts as a seed germinator in parasitic plants, allows mychorizae to recognize the plant and facilitates bud growth) So, if anyone wants I can post more, I just though this was interesting.