Screening of A/Ci-mutant in Arabidopsis thaliana for Identifying Regulatory Elements of the Limiting Factors in Photosynthesis.

Abstract

Objective of our research is to enhance the ability of CO₂-fixation of plants, by improving its photosynthetic performance.
In C3-plants, CO₂-fixation rate at low CO₂ is limited by factors relating to Rubisco-carboxylase reaction, at high CO₂ by factors relating to RuBP-regeneration. In this work, for the identification of regulatory elements of the above limiting factors, we try to screening the Arabidopsis mutants having abnormalities in photosynthesis at low or high CO₂. Photosynthesis rate was estimated as quantum yield of PSII (Φ (PSII)) evaluated from the Chl-fluorescence-image-analysis. Candidates in photosynthesis mutants were grouped into 4-characteristics: 1, high Φ (PSII) at low CO₂, compared to wild type; 2, low Φ (PSII) and no CO₂-dependence; 3, low Φ (PSII) at low CO₂; 4, slow induction of photosynthesis initiation. Identifying gene relating to their phenotype contributes to elucidate the mechanism of photosynthetic regulation with analyzing these mutants in biochemical and physiological traits.