Study On Proteome Of β-carotene Accumulation In Tuberous Roots Of Cassava

Cassava (Manihot esculenta Crantz) belongs to Euphorbiaceae family and Manihot genus, it is a staple food for nearly700million people in the world. The content of protein and carotenoid in tuberous roots of white cassava is low, if edible for a long-term may produce a variety of diseases. β-carotene is the precursor of vitamin A, and its content is an important indicator of nutritional value of cassava. Therefore, the determination of β-carotene content, study on the key enzymes in β-carotene synthesis and differential proteomics research are particularly important, and these are significance for screening cassava germplasm with high carotenoid content.In this study, F1progeny collected from natural hybridization of SC9were as the materials, HPLC was used to measure its β-carotene content, statistics analyze was used for the color and content.6representative cassava strains were selected, gene expression levels and protein levels of LYC-b which is the key genes for β-carotene synthesis were studied, combined with differential proteomics analysis of tuberous roots to explore the molecular mechanisms of β-carotene accumulation, and provide a theoretical basis for selecting high carotenoid cassava varieties. The results are as follows:1. Optimizing the HPLC method to measure β-carotene content in cassava, the mobile phase was methanol:tert-butyl ether (70:30, v/v), flow rate was1.0ml/min, the retention time was about12.7min. The results showed that this method was better for separation, precision and repeatability was good, also for rapid analysis, it was able to meet the requirements of batch testing.2. β-carotene content in tuberous roots was increasing with color (white, cream, yellow, dark yellow). The proportion of white and yellow was1:1in60samples,10%was dark yellow,40%was yellow,13%was cream,37%was white.3. LYC-b expression was not consistency with the color and β-carotene content, while the expression levels of LYC-B enzyme was highest in31-R with high β-carotene.4. Differential proteomics analysis showed:proteins involved in carotenoid synthesis directly or indirectly:Glucose-6-phosphate isomerase, aldolase, enolase, electron transfer flavoprotein-ubiquinone oxidoreductase, succinate dehydrogenation, melanocytes Color P450, glutathione transferase, ascorbate peroxidase, glutathione dehydrogenase, protein disulfide isomerase, AKR, superoxide dismutase, dehydrated fibroin and calmodulin were up-regulated in tuberous roots of31-R and24-R.