Photosynthetic Characteristic Identification Of Eleocharis Baldwinii&the Functional Study Of C3/C4Differentially Expressed Genes

Photosynthesis is the process of plants using solar energy to convert atmospheric CO2into organic compounds, it is one of the most important chemical reactions that supporting living creatures on the earth. C4photosynthesis concentrates CO2at the site of RuBisCO via a series of biochemical and anatomical modifications, forming the carbon concentrating mechanism, thus inhibits photorespiration and reduces the energy consumption in this process. Consequently, compared with C3plant, the major advantages of C4plant are higher photosynthetic energy conversion efficiency, higher water and nitrogen use efficiency as well as more biomass yield.The unsustainable growth of global population is increasing the demands of food. Researchers have been trying to engineering C4cycle into rice, hoping to cultivate C4rice with higher yield to improve grain productivity on limited arable land and meet the needs. In order to achieve this goal successfully, we must have a deep understanding of C4photosynthesis to determine the key genes or regulatory network that can operate to engineer C4system into C3plants. Eleocharis baldwinii is a freshwater amphibious plant, which belongs to Cyperaceae. It can adapt to submerged and terrestrial conditions and grows well in these two different environments. In this study, we investigated the photosynthetic characteristics of E.baldwinii in submerged and terrestrial conditions and chose several differentially expressed genes on the basis of transcriptome datebase to study their functions.The main results of this study are as follows:1. Combine anatomical section, enzymatic activity analysis and stable carbon isotope analysis confirmed that the photosynthetic patterns of E.baldwinii in terrestrial and submerged conditions are C4and C3-C4intermediate respectively.2. Confirmed the chromosome number is20according to the results of chromosome tableting.3. Based on transcriptome date, selected9differentially expressed genes, constructed RNAi vectors for rice homologous sequences (dsOSAl-dsOSA9). Introduced RNAi vectors into Zhonghuall and indentified To generation transgenic plants by PCR analysis and southern blotting. For dsOSA1-dsOSA9each,40,40,38,39,38,39,36,36and39putative transformants were gotten by PCR analysis. Through southern blotting analysis, each obtained12,8,10,7,10,6,11,9and13 single-copy inserted transformed plants. For single-copy inserted transformants, gene expression level were detected by Realtime-PCR.4. Based on transcriptome date, selected9differentially expressed genes, got the full cDNA sequences by RACE. And constructed OE2, OE5two overexpression vectors, transformed into Zhonghuall and indentified To generation transgenic plants by PCR analysis and southern blotting. By PCR analysis,18putative OE2transformants and32putative OE5transformants were gotten. And each obtained5,12single-copy inserted transformants by southern blotting analysis. For single-copy inserted transformants, gene expression level were detected.