Scientists Identify Ozone Resistance Gene

A group of scientists from the University of California, San Diego working with collaborators from Finland, Estonia and England, has identified a gene in Arabidopsis that regulates the amount of atmospheric ozone entering plant leaves. The finding may help explain why increasing carbon dioxide concentration in the atmosphere may not lead to higher photosynthetic productivity or carbon sequestration in plants.

The scientists identified the gene, SLAC1, to be responsible for controlling the opening and closing of plant stomata-tiny pores in leaves where carbon dioxide and water vapor flow during photosynthesis and respiration. SLAC1 is necessary for the function of ion channels in specialized guard cells that surround stomatal pores. When ozone enters the leaf through its stomatal pores, it damages the plant’s light harvesting pigments (resulting to the loss of green color or chlorosis) therefore disrupting the plants’ photosynthetic machinery. To protect themselves, plants close their stomatal pores when concentrations of ozone increase. Although this defense mechanism minimizes the damages of ozone to plants, it also limits their ability to photosynthesize since the stomatal pores are the plant ‘breathing holes’ where carbon dioxide enters.

Scientists seeking ways to develop drought tolerant crops can also exploit the gene since the control of stomatal pore aperture also regulates water loss from plants.

For further information read http://ucsdnews.ucsd.edu/newsrel/science/02-08Ozone.asp