Moss genome sequence reveals how plants invaded land

December 16th, 2007 - 2:52 pm ICT by admin  

Washington, Dec 16 (ANI): The sequencing of a dainty moss called Physcomitrella has revealed as to how plants invaded the land and learned to survive heat and drought.

The mosses are land dwellers that sprout on recently exposed shorelines, quickly fruits, and then die.

The findings were based on a study, led by Jeffrey Boore, a Joint Genome Institute project leader and an adjunct associate professor of integrative biology at the University of California, Berkeley, and chief executive officer of Genome Project Solutions in Hercules, Calif.

The study has shed light on how on a lifeless lakeshore lapped by waves, floating algae learned to survive in the open air and launched an invasion that transformed the Earth into a green paradise.

“Land plants may have evolved in this transition zone where, as the water rises and falls, aquatic plants found themselves repeatedly but not continuously exposed to the air and had to come up with ways of protecting their seeds or spores from desiccation,” said Boore.

“Physcomitrella is to flowering plants what the fruit fly is to humans; that is, in the same way that the fly and mouse have informed animal biology, the genome of this moss will advance our exploration of plant genes and their functions and utility,” said Joint Genome Institute director Eddy Rubin.

Brent Mishler, a UC Berkeley professor of integrative biology who, with Ralph Quatrano of Washington University in St. Louis, Mo., originally proposed the moss genome project said that because of the key position of mosses in the evolution of green plants, the Physcomitrella genome might hold the key to the origin of such traits as desiccation tolerance.

“One of the claims to fame of mosses is the ability to dry up completely and come back to life again,” said Mishler.

“We have been looking for years at all levels, from the organism down to the molecular level, at how mosses do this, and the genome sequence will help speed that work, he added.

Boore said that discovering the genes involved in desiccation tolerance might help plant biologists incorporate the trait into other plants to improve their growth in arid conditions, allowing, for example, bio fuel feedstocks to be grown on marginal land.

In the study, the researchers reported that the Physcomitrella genome contains just under 500 million nucleotides and possesses nearly 36,000 genes, which is about 50 percent more than are thought to be in the human genome.

Physcomitrella is the first nonvascular land plant to be sequenced. Vascular plants lack specialized tissues (phloem or xylem) for circulating fluids, instead possessing specialized tissues for internal transport. They neither flower nor produce seeds, but reproduce via spores.

The study will be published in Science in January 2008. (ANI)

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