岩藻黄素是自然界中最丰富的脂溶性类胡萝卜素，在海洋药物、新型功能食品和保健品开发应用上有巨大的商业前景。岩藻黄素合成途径有许多酶基因未知，这限制了利用生物技术手段改良藻种提高其生产效率。目前尚未有报道从多组学水平全面揭示参与岩藻黄素合成途径的关键基因。球等鞭金藻是最具潜力的岩藻黄素生产制备原料藻之一，我们已破译球等鞭金藻全基因组信息。前期我们发现光质会影响球等鞭金藻单细胞岩藻黄素的积累，然而参与岩藻黄素合成途径的关键基因及其对光质的响应机制尚无研究。本项目拟在前期基础上，通过比较基因组手段和单细胞转录组测序技术从基因组结构水平和单细胞转录水平揭示参与岩藻黄素合成途径的关键基因及其响应不同光质的表达调控网络，预测参与岩藻黄素合成途径的未知酶基因。最后基于CRISPR/Cas9技术在三角褐指藻中验证提高岩藻黄素产量的候选基因，为日后构建高产岩藻黄素球等鞭金藻工程藻株奠定实验和理论基础。

Fucoxanthin is a major carotenoid that accounts for approximately 10% of total natural carotenoid production. Due to its considerable potential applications in human health, the demand for naturally synthesized fucoxanthin in the global market has increased dramatically. The genes involved in biosynthetic pathway of fucoxanthin are not yet fully understood and this hinders the development of low-cost biotechnological approaches for the production of fucoxanthin. No studies have been done yet to uncover genes involved in biosynthesis pathway of fucoxanthin via integrative genomics approaches. Isochrysis galbana is considered as one of the most promising source of fucoxanthin for commercial production, and its complete genome sequence has been fully assembled by our lab for the first time. Our preliminary studies found that green light-emitting diode light could significantly increase fucoxanthin production in Isochrysis galbana, but the essential genes involved in fucoxanthin biosynthesis remain unclear. In this proposal, the available of the Isochrysis galbana genome, combined with the analyses of comparative genomics and single-cell transcriptome will reveal insights into the regulatory gene networks related to the fucoxanthin biosynthesis pathway in response to light regimes in Isochrysis galbana. We will show genes that are critical for the production of fucoxanthin and identify candidate gene that could be the unknown genes in fucoxanthin biosynthesis pathway. Finally, CRISPR/Cas9-based targeted genome editing will be carried out in model algae Phaeodactylum tricornutum to validate candidate genes. The addition of genomics to the experimental toolkit for Isochrysis galbana will make it an attractive alga not only for fundamental studies of its biology but also enhance prospects for improving commercial production of fucoxanthin.