Re: [compost_tea] Systemic bacteria..

From: Thomas Giannou <thomas_at_tandjenterprises.com>
Date: Mon, 24 Nov 2003 23:29:12 -0800

Hi Elaine,

The reason I was asking about bacteria being systemic... I was thinking abo=
ut how many systemic poisons get into plants via the roots. Cygon, for exa=
mple is applied via probe holes. It goes all through the plant and when an=
 aphid takes a bite, that's it for the critter. Systemic is where a chemic=
al or bacteria is spread around a plant via the xylem vascular system. A b=
odily system is used as a transport mechanism, thus the concept, systemic. =
 

I did find that bacteria enter through root hairs according to Bargyla Rate=
aver. I noticed there are quite a few bacterial pathogens that live in the=
 xylem tubes. Many get in through a vectoring agent... like the glassy win=
ged sharpshooter. And then the obvious finally came to mind. As I take a =
metal bar with a pointed end and poke it into the ground around the drip li=
ne of a Quaking Aspen tree, I'm breaking through all kinds of feeder roots.=
  The xylem tubes are wide open in those roots. The bacteria in our mycorr=
hizal fungi product is put down the probe holes, gets into the xylem and ar=
e moved up into every leaf in the plant where they (out compete) with the b=
lack leaf fungi that's common to those kind of trees. If we treat those tr=
ees before the buds open up, the black leaf fungi won't even start up on th=
ose trees. I've seen this happen many times. I'll use the term "out compe=
te" for now because I really don't know what's happening exactly other than=
 the black leaf fungi either stay off the plant or are quickly halted so it=
 does not spread. Besides, there's not a lot of bacteria that will eat up =
fungi, as I recall.

Here's an interesting statement I found at this URL: http://jb.asm.org/cgi/=
content/full/183/12/3597
"Ralstonia solanacearum is a soil-borne gram-negative bacterium that causes=
 bacterial wilt disease in over 200 families of plants, including such main=
stay crops as potatoes, tomatoes, peanuts, tobacco, bananas, and plantains,=
 as well as many native plant species (31). Losses caused by the disease ar=
e known to be enormous but cannot be accurately estimated because of its la=
rge but undocumentable impact on subsistence agriculture and because of the=
 abandonment of wilt-susceptible crops in many parts of the world (31). The=
 pathogen invades plant roots through wounds, notably those created by late=
ral root emergence. Once inside a susceptible host, the bacteria multiply i=
n the cortical tissue before invading the xylem elements. In a matter of ho=
urs, the bacteria spread into the crown and stem through the plant's own va=
scular system, presumably carried along by the transpirational flow (59). S=
ymptoms of bacterial wilt disease include yellowing and wilting, followed b=
y generalized necrosis and death."

It's interesting that a natural function, "lateral root emergence", provide=
s the wound for this pathogenic bacteria to get into a plant. If "Ralstoni=
a solanacearum" can get into a plant that way, then some of our good critte=
rs may be able to get in that way too... it seems logical.

Thanks for the info on the microscope.

Best Regards,
Thomas Giannou
http://www.tandjenterprises.com

----- Original Message -----

  From: soilfoodweb_at_aol.com
  To: compost_tea_at_yahoogroups.com
  Sent: Monday, November 24, 2003 7:39 AM
  Subject: Re: [compost_tea] Systemic bacteria..



  Hi Laura -

  Your example is about organisms living and surviving on the surfaces of t=
he plant roots. I'm glad to see the research about the beneficials STAY th=
ere, if you get them growing and healthy.

  Different from the question about systemic bacteria. The term systemic m=
eans the bacterium has moved inside the plant, and is part of the system, i=
.e, part of the plant.

  Internal contents of plants, like the internal organs and muscles of anim=
als, are sterile. The insides of living organisms tend to be great growth =
media. If a bacterium or fungus gets inside the tissue of an organ, or ins=
ide the muscle tissue, or inside the tissues of the plant, disease is the u=
sual outcome. Just too perfect a growth medium.

  Some bacteria and some fungi have mechanisms for breaching the cell wall =
and cell membrane, and thus are what we think of as pathogenic. It is not =
normal for the SAP of a plant, or the internal tissues of the plant to have=
 any orther organism, besides the plant, present.

  Mycorrhizal fungi are half-way there - they breach the cell wall of the p=
lant, but do not get through the cell membrane. I usually talk about that =
in the introductory lectures I give.

  For a paper to show that the bacteria sprayed onto a leaf surface moved i=
nside the plant, and did not just stay on the surface of the plant, is a sh=
ock. It is not a normal occurrence. What are the conditions that allow th=
is kind of situation to occur. Sterile leaf surfaces, water imbalance, sto=
matal games being played. So, if you mis-treat plants to an extreme, you c=
an end up with compromised plants. You can do that to animals too.

  So, systemic bacteria? We don't find them in plants growing normally. C=
ould conventional ag management result in the conditions necessary to have =
bacteria assault and move into the plant tissue? Hum, yes. Would that hap=
pen using organic ag management? I believe it would not, but darn it, ther=
e's that word believe. The only defense at this point is that there is no =
documentation to suggest it could happen using organic practices.

  Just to summarize - systemic versus living on the surfaces of the roots, =
being present on the next generation of tuber. The first situation is not =
good. The second situation is great. Once a soil is inoculated AND YOU MA=
INTAIN THE HABITAT FOR THE ORGANISMS, allowing the PLANT to feed the benefi=
cials, that set of organisms will survive, multiply, and be on next year's =
tuber. Hooray!

  If you do nothing to kill them, and make sure the habitat is right (food,=
 shelter, good community), the good guys will still be there. You would no=
t need to inoculate again.

  Elaine Ingham
  President, Soil Foodweb Inc.
  SFI Corvallis, OR
  SFI Port Jefferson, NY
  SFI Lismore, NSW, Australia
  SFI Hilversum, The Netherlands
  SFI Cambridge, New Zealand
  www.soilfoodweb.com



Received on Tue Nov 25 2003 - 08:59:48 EST

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