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ARS Has Key Role in Sequence Project Aimed
at Tomato Menace By Luis Pons
The Agricultural Research
Service was among several institutions taking part in a recent project that
sequenced the genome of a microbe that infects tomato plants and whose close
relatives infect many other crops.
The sequencing of the strain of Pseudomonas syringae that
causes bacterial speck disease in tomato plants was led by scientists at
Cornell University in Ithaca, N.Y., and
The Institute for Genomic Research in
Rockville, Md. Funded by the National Science
Foundation in Arlington, Va., the project is featured online today in the
journal Proceedings of the National Academy
Molecular biologist Samuel W. Cartinhour and computational
biologist David J. Schneider, both with ARS'
U.S. Plant, Soil and
Nutrition Research Laboratory in Ithaca, contributed to the joint effort.
Their computational analyses of sequence data helped the research team make
preliminary findings about the roles of the more than 5,500 genes in P.
syringae, including clues as to how it infects plants.
The ARS scientists scanned the sequence to identify a set of
short DNA motifs, known as "hrp boxes," that have an important role in
activating genes involved in plant disease. They also identified a group of
proteins, known as "effectors," that are transported from P. syringae
into plant cells during infection.
While the sequenced strain of P. syringae primarily
affects tomatoes, it also infects Arabidopsis thaliana. That small,
flowering member of the mustard (Brassicaceae) family is widely used as a model
organism in plant biology. The strain thus creates a model pair for plant
In addition, P. syringae is closely related to P.
aeruginosa, which can infect humans and animals, and to P. putida, a
bacterium with uses in environmental cleanup. It also shares a key infection
mechanism with other plant-infecting bacteria.
The Boyce Thompson
Institute for Plant Research in Ithaca, the
University of Nebraska, the
University of Missouri and
Kansas State University also took part in the
ARS is the U.S. Department of
Agriculture's principal scientific research agency.