Dinoflagellates are a major group of protists widely distributed in the aquatic environments. Many species in this lineage are able to form harmful algal blooms (HAB), some even producing toxins, making this phylum the most important contributors of HAB in the marine ecosystem. Despite the ecological importance, the molecular mechanisms underpinning the basic biology and HAB formation of dinoflagellates are poorly understood. While the high-throughput sequencing studies have documented a large and growing number of genes in dinoflagellates, their functions remained to be experimentally proven using a functional genetic tool. Unfortunately, no such tool is yet available. This study was aimed to adopt the RNA interference (RNAi) gene-silencing tool for dinoflagellate research, and to investigate the potential effects of RNAi-based silencing of proton-pump rhodopsin and CO₂-fixing enzyme Rubisco encoding genes in dinoflagellates. It was found that RNAi treatment caused a significant decrease in growth rate in both species. Compared with the non- endogenous target (GFP-siRNA) and the blank control, RNAi treatments also suppressed the expression of the target genes. These results constitute the first experimental evidence of the existence and operation of siRNA in two species of dinoflagellates, present initial evidence that dinoflagellate rhodopsins are functional as a supplemental energy acquisition mechanism, and provide technical information for future functional genetic research on dinoflagellates.

鞭毛藻是在水生环境中广泛分布的主要生物。该谱系中的许多物种都能形成有害的藻华（HAB），有些甚至产生毒素，使该门成为海洋生态系统中HAB的最重要贡献者。尽管具有生态重要性，但对鞭毛藻的基本生物学和HAB形成的分子机制知之甚少。尽管高通量测序研究已证明在鞭毛鞭毛藻中有大量且不断增长的基因，但其功能仍有待使用功能性遗传工具进行实验验证。不幸的是，尚无此类工具。这项研究旨在采用RNA干扰（RNAi）基因沉默工具进行鞭毛鞭毛虫的研究，_二鞭毛藻中的_2-固定酶Rubisco编码基因。发现RNAi处理导致两个物种的生长速率显着降低。与非内源性靶标（GFP-siRNA）和空白对照相比，RNAi处理还抑制了靶标基因的表达。这些结果构成了在两个鞭毛藻物种中siRNA存在和运行的第一个实验证据，提供了鞭毛藻视紫红质作为补充能量获取机制的功能的初步证据，并为将来对鞭毛藻的功能遗传学研究提供了技术信息。