ARS plant physiologist Autar Mattoo, shown here
retrieving plant samples, has found that nitric oxide targets a number of
proteins and enzymes in plants. Click the image for more information about
it.
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Nitric Oxide Regulates Plants as Well as People
By Don Comis
April 28, 2008 Nitric oxide has emerged as an
important signaling molecule in plants as in mammals, including people. In
studies of a tropical medicinal herb as a model plant, researchers have found
that nitric oxide targets a number of proteins and enzymes in plants.
In collaborative work with the research group of Renu Deswal, a faculty
member, and her doctoral student at the
Botany
Department, University of Delhi, India,
Agricultural Research Service (ARS)
scientist
Autar
Mattoo has identified 19 such targeted proteins and enzymes in Kalanchoe
pinnata, also known as "miracle leaf." Mattoo is a plant
physiologist with the
ARS
Sustainable Agricultural Systems Laboratory, Beltsville, Md. ARS is the
chief scientific research agency of the U.S.
Department of Agriculture.
The targeted proteins and enzymes are involved in regulating processes from
seed germination and cell development to plant death. Notably, they also
regulate many other important processes, including photosynthesis, sugar
metabolism, disease tolerance and stress tolerance in plants.
The collaborative research suggests that the effects of nitric oxide, a
sometimes toxic byproduct of nitrogen oxidation in soil, may have broader
implications in plant processes than previously realized. Its modification of
proteins, a process called S-nitrosylation, is increasingly recognized as a
ubiquitous regulatory reaction in plants and mammals.
Mattoo and Deswal have shown for the first time that nitric oxide
inactivates Rubisco, a major enzyme involved in carbon dioxide fixation and
photosynthesis in plants.
Kalanchoe represents plants that have a unique method of carbon
dioxide fixation that is shared by succulent plants. Kalanchoe has
diverse possible medicinal benefits, suggesting the presence of interesting
processes at work. Mattoo hopes to do similar studies with major crops grown in
different production systems, with the goal of improving both crop yields and
quality, including nutritional benefits.
Other scientists have studied nitric oxide targets in the most common model
plant, Arabidopsis. Mattoo and collaborators found that Kalanchoe
had some nitric oxide targets in common with Arabidopsis, such as
Rubisco and drought-protective proteins. They also found new protein targets in
Kalanchoe that have not been reported previously.
A paper discussing these results is available online at the FEBS Journal website.