Phytoplankton are major contributors of labile dissolved organic matter to marine euphotic zone ecosystems. Viral‐mediated phytoplankton lysis releases a considerable amount of bioavailable cellular contents and facilitates localized heterotrophic bacterial growth. The rapid turnover times of this labile organic matter renders it difficult to trace their transformation within natural environments. In the present study, we used a model phototroph‐heterotroph coculture system to investigate the organic molecular variation during cyanophage‐induced Synechococcus lysis and post‐lysis periods using fluorescence spectroscopy and ultrahigh resolution mass spectrometry analyses. Approximately 80% of the Synechococcus lysates were respired to carbon dioxide within 2 days coupled to rapid regeneration of inorganic nutrients. Five fluorescent dissolved organic matter components were detected in the incubations including four humic‐like and one protein‐like components, and their abundances varied markedly with the succession of the viral lysis process. Viral lysis promoted the transformation of Synechococcus biomass to dissolved organic matter, and heterotrophic bacterial metabolism facilitated the transformation of organic molecules from relatively high (avg. ~ 430 Da) to low (avg. ~ 360 Da) molecular weight, corresponding to variation in their bioavailability. The Synechococcus‐derived organic matter was highly enriched in N‐containing organic molecules. Identified metabolites within the cultures primarily comprised amino acids or oligopeptides and other low‐molecular‐weight organic acids, carbohydrates, nucleotides, lipids, biogenic amines, and porphyrins. Among these, oligopeptides, nucleotides, and lipid compounds significantly increased with viral lysis. These results provide insight into biogeochemical cycling mediated by viral shunts in oceans, thus deepening our understanding of microbial food webs at the molecular level.

中文翻译：

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球菌溶胞产物中富含N的有机分子及其被异养细菌快速转化

浮游植物是不稳定的溶解有机物对海洋富营养区生态系统的主要贡献者。病毒介导的浮游植物裂解释放大量生物利用的细胞，并促进局部异养细菌的生长。这种不稳定的有机物的快速周转时间使其难以追踪其在自然环境中的转化。在本研究中，我们使用的模型光合有机体-异养共培养系统来研究期间噬蓝藻诱导的有机分子变异聚球使用荧光光谱法和超高分辨率质谱分析裂解和后裂解周期。约80％的球菌裂解液在2天之内被吸入二氧化碳，并与无机养分迅速再生。孵育过程中检测到5种荧光溶解的有机物成分，包括4种腐殖质样和1种蛋白质样成分，其丰度随着病毒裂解过程的连续性而显着变化。病毒裂解促进转化聚球蓝细菌生物质以溶解的有机物质，和异养细菌的代谢促进有机分子的转化从相对高的（平均〜430道尔顿）至低（平均〜360道尔顿）的分子量，对应于变化其生物利用度。在聚球藻源自有机物的含氮有机分子高度丰富。培养物中鉴定出的代谢产物主要包括氨基酸或寡肽以及其他低分子量有机酸，碳水化合物，核苷酸，脂质，生物胺和卟啉。其中，寡肽，核苷酸和脂质化合物随着病毒裂解而显着增加。这些结果为深入了解海洋中病毒分流介导的生物地球化学循环提供了依据，从而加深了我们对微生物食物网的分子水平的了解。