Date: Mon, 8 Feb 1999 08:52:05 -0500 From: "Mellard, David" <dam7@cdc.gov> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg376$foo@default> Subject: RE: Anthocyanins Out (off-topic?)
>I am trying to discover or breed an anthocyanin-free form of a
>non-carnivore (heresy!). Does anyone know why anthocyanin-free forms
>arise, or has anyone noticed anything unusual about the conditions in
>which anthocyanin-free forms appear, eg Darlintonia 'Othello', the
>heterophyllous S purpureas and Drosera capensis 'alba'.
Hi Nigel,
Anthocyanin production in Sarracenia involves two pathways that start with
the 2-carbon molecule acetic acid. Once the pathways merge, 5 enzymes are
responsible for producing the anthocyanin pigment. A mutation that
inactivates any of the 5 molecules will produce an anthocyanin-free plant.
Cultural conditions can also affect anthocyanin production, although I don't
think it's know exactly why (or how) it interrupts anthocyanin production.
I suspect that a mutation earlier in one of the two pathways before they
merge will affect the amount of anthocyanin produced thus affecting
coloration. For instance, if one of the two pathways is inactivated, the
plant has only 1 of the early pathways to use in producing anthocyanin.
This results in a smaller amount of anthocyanin and hence less color.
Smaller amounts of anthocyanin production can probably happen with mutations
after the pathways merge if an enzyme is produced that is only partially
efficient in converting the pre-anthocyanin molecule to the next molecule in
the pathway.
It would be interesting to breed the anthocyanin-free form of S. purpurea
venosa that ABG recently released with the anthocyanin-free form of S.
purpurea purpurea. Since they evolved in different locations, there's a
good chance that the mutations are on different genes. If normal color
purpurea were produced from that cross, you've just proved that the genetic
mutations are on different genes and hence involve different enzymes.
Chromatography will also give this answer because you can see which enzymes
are missing. I have both plants and hope someday to cross them when they
bloom. You could do this with any Sarr antho-free forms, too. Now, I've
just given someone a very nice CPN article if your plants are more mature
than mine.
CPN had a nice article on anthocyanin production in 1998. I have it on file
and will send it to you if you send me a private reply.
David
Atlanta
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