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2-Plants: Sustainable agriculture activates tomato genes

                                 PART I
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TITLE:  Sustainable agriculture activates tomato genes
SOURCE: PNAS Online Early Edition
DATE:   5 Jul 2004

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Sustainable agriculture activates tomato genes

Sustainable agriculture farming techniques promote higher levels of
proteins that boost plants' immune defenses and enhance longevity, a new
report says. The results show how a group of proteins involved in
nitrogen and carbon fixation, as well as cell defense, work more
effectively in plants grown under natural fertilization conditions versus
plants grown under chemical fertilization. Autar Mattoo and coworkers,
working at a Maryland farm site, studied the differences in growth
patterns, plant health, and gene expression between tomato plants grown
in a mulch of black polyethylene or in a leguminous based mulch. The
tomato plants grown in the organic mulch lived longer, had longer-lasting
leaves, and showed increased disease tolerance. The team says the
leguminous mulch provides a regulated supply of carbon, nitrogen, and
other elements that the tomatoes use more efficiently than the nutrients
provided by direct fertilization of black polyethylene. The increased
nutrients led to significantly higher amounts of gene expression in more
than 10 genes. The result provides further evidence that sustainable
farming practices are a viable alternative to chemically-intensive
agriculture and identifies some of the first genes that are expressed
differently under the two conditions.

Article #03496: "An alternative agriculture system is defined by a
distinct expression profile of select gene transcripts and proteins" by
Vinod Kumar, Douglas J. Mills, James D. Anderson, and Autar K. Mattoo

                                 PART II
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TITLE:  Tomatoes Get Genetic "Boost" Under Sustainable Ag System
SOURCE: U.S. Department of Agriculture, by David Elstein
DATE:   6 Jul 2004

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Tomatoes Get Genetic "Boost" Under Sustainable Ag System

Tomatoes grown in a sustainable agricultural system using a legume cover
crop as fertilizer had better disease resistance and lived longer than
tomatoes grown on black polyethylene mulch with chemical fertilizer,
Agricultural Research Service scientists report.

Based on a five-year sustainable agriculture study, the results are
published in the current issue of the Proceedings of the National Academy
of Sciences. ARS is the U.S. Department of Agriculture's chief scientific
research agency.

The scientists showed that at least 10 genes in the leaves of tomatoes
grown in the sustainable system were turned on longer, or "over-
expressed," allowing those tomatoes to live longer than tomatoes grown on
the plastic mulch. These "over-expressed" genes may respond to signals
emanating from the specific ratio of nitrogen, carbon and other elements
provided by the cover crop.

The researchers compared the two tomato cultivation systems at the ARS
Henry A. Wallace Beltsville (Md.) Agricultural Research Center. In one
system, tomatoes were grown under the traditional method of black
polyethylene mulch with chemical fertilizer, a common planting regimen in
the Middle Atlantic and Southeastern states.

In the other planting system, the scientists grew tomatoes in the
sustainable system, in which the plants received half the chemical
fertilizer and fungicide applied in the traditional system. The
sustainable system relied on hairy vetch--a nitrogen-fixing legume cover
crop--to provide soil nutrients and some natural leaf disease protection.

The scientists also believe the cover crop allows the tomato root system
to produce increased levels of cytokinins, a class of plant hormones that
delay senescence and let the plant live longer.

With the genes identified that impart disease tolerance and longevity,
researchers may be able to use that knowledge to breed plants that are
even more highly responsive to sustainable production systems.

The research was conducted by Autar K. Mattoo and Vinod Kumar of the ARS
Vegetable Laboratory, Beltsville; James D. Anderson of the ARS Plant
Sciences Institute, Beltsville; and Douglas J. Mills, now at Georgia
State University, Atlanta.


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