Yale University researchers have now identified a key
genetic gear that keeps the circadian clock in plants ticking
Circadian rhythms are a roughly 24-hour cycle governing
biochemical, physiological, or behavioral processes that have
been widely observed not only in humans, but other animals,
fungi, cyanobacteria and plants. In plants, circadian rhythms
help synchronize biological processes with day and night to
control photosynthesis, tell the plant what season it is, and
the best time to flower to attract insects. Yale University
researchers have now identified a key genetic gear that keeps
the circadian clock in plants ticking, offering the prospect of
engineering plants that can grow all year round and in locations
where that's not currently possible.
Scientists have known for some time that plants' circadian
clocks operate through the cooperative relationship between
"morning" genes and "evening" genes. Proteins encoded by the
morning genes suppress evening genes at daybreak, but by
nightfall the levels of these proteins drop and evening genes
are activated again. These evening genes are actually necessary
to turn the morning genes on and complete the 24-hour cycle, but
scientists weren't certain of the exact processes involved. By
identifying the gene DET1 as crucial in helping to suppress
expression of the evening genes in the circadian cycle, the Yale
researchers have solved one of the last remaining mysteries in
this process.
"Plants that make less DET1 have a faster clock and they take
less time to flower," said On Sun Lau, a former Yale graduate
student who is now at Stanford University and is lead author of
the study that appears in the Sept. 2 issue of the journal
Molecular Cell. "Knowing the components of the plant's
circadian clock and their roles would assist in the selection or
generation of valuable traits in crop and ornamental plants."
"Farmers are limited by the seasons, but by understanding the
circadian rhythm of plants, which controls basic functions such
as photosynthesis and flowering, we might be able to engineer
plants that can grow in different seasons and places than is
currently possible," added Xing Wang Deng, the Daniel C. Eaton
Professor of Molecular, Cellular, and Developmental Biology at
Yale and
senior author of the paper.
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