Edinburgh, Scotland, United Kingdom - TAIR

Identification of CO 2 -binding proteins that
function as upstream mediators of CO 2induced
stomatal movements
Guard cells form stomatal pores in the plant epidermis that allow CO 2 influx for
photosynthesis and transpirational water loss from plants. The continuing rise in
atmospheric CO 2 causes closing of stomatal pores in leaves and thus globally
regulates CO 2 influx into plants, leaf heat stress, and plant water use efficiency.
However, the CO 2 binding proteins and mechanisms that control this CO 2
response remain unknown. Moreover, the cell type that responds to CO 2 -
mesophyll cells or guard cells - and whether photosynthesis mediates this CO 2
response remain matters of debate, with a need for genetic investigation. New
findings will be presented showing that Arabidopsis mutant plants in leafexpressed
CO 2 binding proteins (CO 2 Responsive Protein: CORP) display
strongly impaired CO 2 -regulation of gas exchange and CO 2 -regulated stomatal
movements, but retain functional abscisic acid and blue light responses. Data will
be presented demonstrating whether CORP-mediated stomatal CO 2 signaling is
directly linked to photosynthesis and which leaf cell type mediates this response.
Interestingly, tissue-specific targeted over-expression of CORP in wild-type
plants greatly enhances water use efficiency. These findings, together with
epistasis and biochemical CO 2 response analyses demonstrate that CORP
functions early in the stomatal CO 2 signaling pathway and initiates CO 2 control
of gas exchange between plants and the atmosphere.
59
C08
Wednesday 14:25 - 14:50
Environmental Responses
Julian Schroeder
Honghong Hu
Aurélien Boisson-Dernier
Maria Israelsson-
Nordström
Maik Böhmer
Shaowu Xue
Jan Godoski
Amber Ries
University of California
San Diego
La Jolla
CA
USA