Unusual Hybrid Sparaxis
Nathan Lange (Thu, 13 Jun 2013 12:08:36 PDT)

Because many, if not most, plants are infected with innocuous
viruses, a positive test for their presence is of little value and
does not establish cause and effect. Since Barbara McClintock's
oringinal Nobel-winning research into transposable elements in Maize,
a large body of research has been amassed on the genetic origins of
variegated flower color patterns. While there may be a very remote
possibility that this Sparaxis flower color pattern might be caused
by a virus (I doubt it), the pattern itself is highly indicative of a
transposon jumping into and out of a gene involved in the expression
of the pigment in the petals at some point during the early
development of the flowers.

By the way, if you look at (Google) some examples of McClintock's
colorful and speckled Maize kernels (think Indian corn), you probably
might incorrectly think there is a virus involved.

I found a good description here of how a transposon causes this type
of variegated flower pattern:
http://stanford.edu/group/dahlia_genetics/…

Nathan

At 09:33 AM 6/13/2013, you wrote:

On Thu, Jun 13, 2013 at 7:07 AM, Mary Sue Ittner <msittner@mcn.org> wrote:
I sent those in for testing I sent in something that looked

suspicious to me and it was fine. It left me feeling that it may be
challenging to tell by looking what is virused.

I suspect that the lab only looked at the type of virus (if the tests
are available) but they didn't look at the amount of viruses. The
concentration (titer) of viruses in an infected tissue probably
determines the prevalence of mosaic. Some plants can keep that titer
down but others cannot. Unfortunately, virus research in bulbs is few
and far in between and we still don't know much about them in
non-commercial bulbs.

Since we cannot be sure which ones are virused and which ones are not,
I suggest that growing your own plants from seeds is the best way to
go. Getting bulbs from a reliable grower/friend is also another good
way to go about it.

Nhu
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