Tomato Bacteria May Benefit Human Infection Cure
Research at the Boyce Thompson Institute for Plant Research centers around knowing which bacterial proteins cause infection, which may lead to a mechanism that will stop tomato speck bacteria from injecting them into plant cells. "Just understanding fundamental processes about how the bacteria infects hosts will give us new targets to be
able to go in and interfere with the infections," said Greg Martin in a mid-August interview. Pseudomonas syringae, which is ubiquitous and causes tomato speck, is related to a bacterium that causes illness in humans. Tomato speck usually doesn't wipe out crops, but it is persistent. Farmers rely on copper-based sprays to kill the bacterium, but it is becoming resistant. In humans, Pseudomonas aeruginosa attacks those with weak immune systems, causing symptoms such as rashes and nausea. Patients with the lung disease cystic fibrosis can suffer heart failure if they become infected. Pseudomonas aeruginosa also can cause ear infections and meningitis, which inflames tissue in the brain and spinal cord.
Doctors are faced with the same problem as farmers - the bacteria is becoming resistant to the antibiotics they depend on to kill it. Dennis Ohman, a microbiologist at Virginia Commonwealth University, said he and other researchers can use the sequenced genome of tomato speck to learn more about the human infection. "They're very similar organisms," said Ohman, who is on a team studying the genome of Pseudomonas aeruginosa. "A lot of the same factors that were prevalent in plant disease were there in human disease as well. The human disease and plant disease may not be all that different." Plant scientists found there are more than 5500 genes, or proteins, in tomato speck. Of those, as many as 50 are key in spreading infection, Martin said. The bacterium "has an amazing way of injecting them into the host cell," he said. "It develops a little syringe-like structure, pokes a hole into the host cell, and then it starts injecting these proteins." The findings were published on August 20, 2003 in the journal Proceedings of the National Academy of Sciences. (Royal Society News, 8/22/03 via AgNet).
