Researchers have discovered two genes that guide land plants to develop microscopic pores that they can open and close as if each pore was a tiny mouth.
Plants wouldn't have been able to move from water to land 400 million years ago if they hadn't evolved this ability, which protects them from losing too much moisture.
The leaves and stems of land plants are dotted with the "tiny mouths," called stomata. When open, stomata allow the plant to take in carbon dioxide gas needed for photosynthesis and allow moisture to evaporate, pulling water from the roots into the plant. But when too much moisture is being lost, the two cells around the stomatal pore close it completely.
Without the genes guiding stomatal development, plants won't develop any mouthlike pores, hence the names Speechless and Mute for the newly discovered genes, according to Keiko Torii, a University of Washington associate professor of biology.
Two separate papers on the genes, one by Torii's UW group and the other by Stanford University researchers, have been published online by Nature, and are scheduled to appear in the print publication Feb. 1. Each group describes independently finding the gene that came to be called Speechless and its role in initiating the process that leads to stomata.
In addition, Torii's UW group published findings in its Nature article about another gene, one they named Mute, that triggers the key middle step that decides when a cell will fully become a stomata. Earlier this year the Stanford group published findings about the gene that controls the final step in stomata development, called Fama.
"In the last few months, we've gone from knowing surprisingly little about the genes involved to knowing all three major factors Speechless, Mute and Fama," says Lynn Pillitteri, a research associate in biology and lead author of the Nature paper.
That the three are so closely related will be of interest to biologists studying both plant
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Contact: Sandra Hines
shines@u.washington.edu
206-543-2580
University of Washington
18-Jan-2007