Research
| Title： | Identification and Biotechnical Potential of a Gcn5-Related N-Acetyltransferase Gene in Enhancing Microalgal Biomass and Starch Production |
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| First author： | Li, Zhongze; Cao, Li; Zhao, Liang; Yu, Lihua; Chen, Yi; Yoon, Kang-sup; Hu, Qiang; Han, Danxiang |
| Journal： | FRONTIERS IN PLANT SCIENCE |
| Years： | 2020 |
| DOI： | 10.3389/fpls.2020.544827 |
| Abstract： | Microalgae are promising feedstocks for starch production, which are precursors for bioenergy and chemicals manufacturing. Though starch biosynthesis has been intensively studied in the green algaChlamydomonas reinhardtii, regulatory mechanisms governing starch metabolism in this model species have remained largely unknown to date. We proposed that altering triacylglycerol (TAG) biosynthesis may trigger intrinsic regulatory pathways governing starch metabolism. In accordance with the hypothesis, it was observed in this study that overexpression of the plastidial lysophosphatidic acid acyltransferase gene (i.e.LPAAT1) inC. reinhardtiisignificantly enhanced TAG biosynthesis under nitrogen (N)-replete conditions, whereas the starch biosynthesis was enhanced in turn under N depletion. By the exploitation of transcriptomics analysis, a putative regulatory gene coding Gcn5-related N-acetyltransferase (GNAT19) was identified, which was up-regulated by 11-12 times in theCrLPAAT1OE lines. Overexpression of the cloned full-lengthCrGNAT19cDNA led to significant increase in the starch content ofC. reinhardtiicells grown under both N-replete and N-depleted conditions, which was up to 4 times and 26.7% higher than that of the empty vector control, respectively. Moreover, the biomass yield of theCrGNAT19OE lines reached 1.5 g L(-1)after 2 days under N-depleted conditions, 72% higher than that of the empty vector control (0.87 g L-1). Overall, the yield of starch increased by 118.5% inCrGNAT19OE lines compared to that of the control. This study revealed the great biotechnical potentials of an unprecedentedGNAT19gene in enhancing microalgal starch and biomass production. |
