Why we should care about pathogenic viruses in our plants
Nhu Nguyen (Fri, 23 Jul 2010 11:05:50 PDT)

Hi Lee and all,

Your note about the USDA viral rescue is really fascinating. We just have to
learn how to grow our bulbs from tissue culture and we can perhaps do some
of that. It's much easier said than done!

Antibody production is part of the active immunity, which as far as I know
is only present in higher animals (mammals, etc...). Even animals such as
insects don't have active immunity. So Adam's guess about no antibodies is
correct. Vaccines trigger active immunity systems to ramp up and start the
production of antibodies. Many living organisms don't have active immunity,
and that includes plants. Instead, these organisms have passive immunity,
and in plants is represented by production of certain compounds which then
interact with cellular mechanisms to fight off disease.

The link that Jim sent talks about salicylic acid (which can be extracted
from willow bark - Salix::salicylic). Salicylic acid has been shown to help
plants ramp up their immune defense. Adam mentioned drenching his plants
with aspirin and we can connect these two points. Aspirin is a derivative of
salicylic acid and it is chemically similar enough to salicylic acid that
perhaps it can help to trigger plant defense. So perhaps willow bark extract
may be a more efficient than aspirin? Anyone interested and give this a try.

Uromyces is a rust and these are *expert* at infecting plants. They have
co-evolved with plants for millions of years and have most likely found ways
to avoid plant defenses. They are after all obligate parasites and if they
can't avoid plant defenses, they cannot survive.

Nhu
Berkeley, CA

On Fri, Jul 23, 2010 at 6:36 AM, Lee Poulsen <wpoulsen@pacbell.net> wrote:

3. Which leads me to a third comment/question: I am not a biologist, just
someone very scientifically oriented and interested in many aspects of
science. However, even though I've read and heard a lot about how the human
body (and animals in general) fights viruses, antibodies, etc., I have
utterly no knowledge about how or whether plants fight viruses. Do they
produce antibodies? Do they have some other mechanism to do so? It would
seem that they have to do something or else by now the entire plant kingdom
would be either completely infiltrated with evolved viruses, or extinct. If
there is such a mechanism, wouldn't it be possible to develop the equivalent
or analog of vaccines for plants? They've made vaccines for pet animals and
agricultural animals; have they tried creating the equivalent of vaccines
for important commercial crops, and it not, is it because such a thing is
not possible? (I realize that geophytes are far down the list in importance
for making "vaccines" against viruses. But I'm curious about why I've never
heard of medical methods to prevent virus infection in plants.)

--
http://www.flickr.com/photos/xerantheum/