Cloning and Expression Analysis of Chlorophyll a Oxygenase Gene in Wheat

【Objective】 Chlorophyll a oxidase (CAO) is the key enzyme for the synthesis of chlorophyll b. This project aims to study the changes of TaCAO expression level in low light environment and explore the response of chlorophyll synthesis pathway to low light environment. 【Methods】 TaCAO was cloned from Xindong 20 by homologous cloning, and the sequence was analyzed. The semi-quantitative PCR method was used to analyze the expression of TaCAO under 900 lx, 1,800 lx, 3,600 lx and 7,200 lx light intensity. 【Results】 The ORF length of this gene was 1,653 bp, the size of the encoded protein was 62.12 kD, containing 550 amino acid residues with the chlorophyll transit peptide and Rieske_RO_Alpha_CAO domain, and there was also a Rieske iron-sulfur coordination center and iron binding site. With the decrease of light intensity, the expression of TaCAO showed an upward trend. 【Conclusion】 The cloned TaCAO is 1,653 bp in length and has complete CAO activity. The relative expression of TaCAO has an inverse relationship with the light intensity.