Successful establishment of an exogenous gene expression system in Chlamydomnas chloroplast based on viral replication elements

Abstract

Currently, transformation in unicellular green alga (Chlamydomonas reinhardtii) chloroplast is hindered by a low yield of target products, possibly due to the heterogeneity of the chloroplast genome. In this study, an expression platform was established in C. reinhardtii by leveraging replicative elements from beet curly top geminivirus, which led to a high level of heterologous gene expression, as previously reported in Nicotiana tabacum. Platform performance was verified by the successful expression of a linearized mvenus cassette, achieving a higher expression level than that obtained using the homologous-recombination-based approach. This study provides a new strategy in microalgae synthetic biology and opens new avenue for accumulating valuable bioproducts at high concentrations.