Chen Jiawei, Deng Lixia, Pang Mengwen, Li Yingdong, Xu Zhimeng, Zhang Xiaodong, Liu Hongbin
Department of Ocean Science, Hong Kong University of Science and Technology, Hong Kong SAR, China.
Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya, China.
ISME Commun. 2024 Jun 19;4(1):ycae087. doi: 10.1093/ismeco/ycae087. eCollection 2024 Jan.
The shift between photoautotrophic and phagotrophic strategies in mixoplankton significantly impacts the planktonic food webs and biogeochemical cycling. Considering the projected global warming, studying how temperature impacts this shift is crucial. Here, we combined the transcriptome of in-lab cultures (mixotrophic dinoflagellate sp.) and the metatranscriptome dataset of the global ocean to investigate the mechanisms underlying the shift of trophic strategies and its relationship with increasing temperatures. Our results showed that phagocytosis-related pathways, including focal adhesion, regulation of actin cytoskeleton, and oxidative phosphorylation, were significantly stimulated in sp. when cryptophyte prey were added. We further compared the expression profiles of photosynthesis and phagocytosis genes in sp. in the global sunlit ocean. Our results indicated that sp. became more phagotrophic with increasing temperatures when the ambient chlorophyll concentration was >0.3 mg.m (20.58% of the ocean surface) but became more photoautotrophic with increasing temperatures when the chlorophyll concentration was between 0.2 and 0.3 mg.m (11.47% of the ocean surface). Overall, we emphasized the crucial role of phagocytosis in phago-mixotrophy and suggested that the expression profile of phagocytosis genes can be a molecular marker to target the phagotrophic activity of mixoplankton in situ.
混合浮游生物中光合自养和吞噬营养策略之间的转变对浮游食物网和生物地球化学循环有重大影响。考虑到预计的全球变暖，研究温度如何影响这种转变至关重要。在这里，我们结合了实验室培养物（混合营养型甲藻）的转录组和全球海洋的宏转录组数据集，以研究营养策略转变的潜在机制及其与温度升高的关系。我们的结果表明，当添加隐藻猎物时， 中与吞噬作用相关的途径，包括粘着斑、肌动蛋白细胞骨架调节和氧化磷酸化，受到显著刺激。我们进一步比较了全球阳光照射海洋中 中光合作用和吞噬作用基因的表达谱。我们的结果表明，当环境叶绿素浓度>0.3 mg·m（约占海洋表面的20.58%）时， 随着温度升高变得更具吞噬营养性，但当叶绿素浓度在0.2至0.3 mg·m之间（约占海洋表面的11.47%）时，随着温度升高变得更具光合自养性。总体而言，我们强调了吞噬作用在吞噬混合营养中的关键作用，并建议吞噬作用基因的表达谱可以作为一个分子标记，用于原位靶向混合浮游生物的吞噬营养活性。
