plant pathogen Pseudomonas solanacearum

Ron Gitaitis path4 at tifton.cpes.peachnet.edu
Thu Nov 2 11:15:18 EST 1995

>One of my undergraduates is interested in a project
>involving Pseudomonas solanacearum.  He wants to grow
>the bacterium on tomato plants in the green house.
>My questions are:
>        1) Is this organisms pathogenic to humans?
>        2) Will this organism infect other plants in the greenhouse?
>           If so, are there mechanisms to protect the other plants?
>Thanks in advance for any help you may be able to provide.
>Frank Pascoe
>College of St. Francis
>Joliet, IL
Pseudomonas solanacearum syn (Burkholderia solanacearum) in a strict
sense is not pathogenic to humans.  However, there have been some very rare
cases of plant pathogenic bacteria crossing over and causing infections in
humans when these bacteria invade a wound or take advantage of colonizing
a host whose resistance is in a very weakened condition.  Using good
laboratory procedures and common sense precautions, B. solanacearum should
not cause any health risk to the student.
B. solanacearum has an extremely wide host range that includes many
solanaceous plants including tomato, potato, bell pepper and eggplant.
Specific strains and races also infect peanut, tobacco, and banana.  Overall
there are probably over a 100 known hosts worldwide.
It is primarily soilborne and infection occurs through the roots,
although mechanical transmission can occur through man's activities.
If the soil in the pots containing the infected plants does
not come in contact with soils of other plants, the risk of dissemination
in the greenhouse is minimal.  Other ways of spreading it in the
greenhouse are by mechanical wounding (such as removing buds from
one plant and not sanitizing the pruning shears or fingers before moving
on to the next plant) or through water draining out of a pot and making
contact with another potted plant (e.g. if both plants were in the same
large tray that held water thus creating an aqueous highway from plant to
The bacterium does not survive in nature very well north of Virginia/North
Carolina, but good laboratory protocol would require you to sterilize the
contaminated soil and plant debris before you discarded them.  Also, it is
my guess that if you do not already have a culture of this bacterium
you will be required to file a PPQ 526 request with APHIS to import
a plant pathogen in to the state of Illinois.
Ron Gitaitis
Professor of Plant Pathology
Coastal Plain Experiment Station
University of Georgia
Tifton, GA

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