Mechanistic insights into Ginkgo-nerolidol compound preparation against the bloom-forming dinoflagellate Prorocentrum...

Prorocentrum donghaiense is a major bloom-forming species in the East China Sea and has severe adverse effects on marine ecosystems. To address this issue, the development of efficient and eco-friendly algal inhibitors is essential. However, research in this area remains limited. In this study, Ginkgo biloba extract (GB), nerolidol (NE), and a compound preparation (GN = GB + NE) were selected as algae-inhibiting materials, and the mechanisms of action of GB, NE, and GN on P. donghaiense were analyzed via RNA-seq. In total, 59,151, 152, and 25,363 differentially expressed genes (DEGs) were identified in algae treated with GB, NE, and GN, respectively. The top three GO- and KEGG-annotated DEGs were shared between GB and GN treatments, indicating that GB was the primary active component of GN. KEGG enrichment further showed that photosynthesis-related pathways were among the top five pathways affected by GN. Key genes in photosystem II (PsbA-E), cytochrome b₆/f complex (PetD), and ATP synthase (atpD) were downregulated, and 10 photosynthesis-antenna protein genes (Lhca1-4, Lhcb1-6) were upregulated under GN treatment. However, most of these genes did not show significant expression under the GB treatment, except for Lhca1 and Lhcb1-2. Furthermore, NE treatment upregulated ushA and downregulated pncC, disrupting algal nucleotide and NAD⁺ biosynthesis. This suggests that NE may accelerate GB-induced inhibition of photosynthesis-related pathways. These findings provide new insights into the molecular mechanisms underlying P. donghaiense exposure to GN and provide a theoretical basis for the prevention and control of harmful algal blooms.