Researchers decode genetics of rare photosynthetic...( TEMPE Ariz. A bacterium that harves...)

TEMPE, Ariz. A bacterium that harvests far-red light by making a rare form of chlorophyll (chlorophyll d) has revealed its genetic secrets, according to a team of researchers who recently sequenced the bacterias genome.

The researchers, from Arizona State University and Washington University, St. Louis, report in the current online edition (Feb. 4) of the Proceedings of the National Academy of Sciences, that they have sequenced the genome of the cyanobacterium, Acaryochloris marina, which through its production of chlorophyll d can absorb red edge, near infrared long wavelength light -- light that is invisible to the naked eye. Acaryochloris marina has a massive genome (8.3 million base pairs) and is among the largest of 55 cyanobacterial strains in the world. It is the first chlorophyll-d containing organism to be sequenced.

The advance has applications in plant research, said Jeffrey Touchman, an assistant professor ASUs School of Life Sciences and lead author of the paper, Niche adaptation and genome expansion in the chlorophyll d-producing cyanobacterium Acaryochloris marina.

Chlorophyll d harvests light from a spectrum of light that few other organisms can, and that enables this organism to carve out its own special niche in the environment to pick up far-red light, Touchman explained. The agricultural implications could be significant. One could imagine the transfer of this biochemical mechanism to other plants where they could then use a wider range of the light spectrum and become sort of plant powerhouses, deriving increased energy by employing this new photosynthetic pigment.

There is a bioenergy link to this work, said Touchman, who is a member of ASUs Center for Bioenergy and Photosynthesis. It could be used for crops that are turned into fuels or to generate biomass.

Touchman worked with Robert Blankenship of Washington University on the sequencing project, which involved collaborators from Australia
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