Cryptic bacterial pathogens of diatoms peak during senescence of a winter diatom bloom.
Cryptic bacterial pathogens of diatoms peak during senescence of a winter diatom bloom.
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硅藻的隐性细菌病原体在冬季硅藻花的衰老过程中达到顶峰。
DOI：
10.1111/nph.19441
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Branscombe L
中科院分区：
文献类型：
--
作者：
Branscombe L
硅藻是全球范围内丰富的微藻，在水生生态系统中形成广泛的水华。某些细菌对硅藻表现出敌意，杀死或抑制它们的生长。尽管它们对硅藻水华和种群健康具有重要影响，但对环境中硅藻拮抗剂的了解基本上是缺乏的。我们报告了在硅藻频繁爆发的西英吉利海峡(WEC)通过菌斑分析采样系统地表征硅藻细菌拮抗剂的多样性和季节动态。出乎意料的是，检测到的峰值并不出现在特征的春季硅藻开花期间，而是与科西尼圆盘藻冬季开花的时间重合，这表明这些细菌可能影响不同的硅藻寄主种群。值得注意的是，多次分离到一种附着在玫瑰杆菌亚历山大杆菌上的硅藻，这表明环境中持续存在。此外，许多分离物对硅藻没有拮抗活性的先前报道。我们验证了8个菌株对硅藻生长的抑制作用。在所有被测试的案例中，这些效应都是通过预先接触硅藻有机物来激活的。广泛的“隐蔽”拮抗活性的发现表明，细菌对硅藻的致病性比以前认识的更普遍。最后，对WEC拮抗剂的全球生物地理学研究发现，全球海水中的硅藻宿主种群存在共生模式。
Diatoms are globally abundant microalgae that form extensive blooms in aquatic ecosystems. Certain bacteria behave antagonistically towards diatoms, killing or inhibiting their growth. Despite their crucial implications to diatom blooms and population health, knowledge of diatom antagonists in the environment is fundamentally lacking.We report systematic characterisation of the diversity and seasonal dynamics of bacterial antagonists of diatoms via plaque assay sampling in the Western English Channel (WEC), where diatoms frequently bloom. Unexpectedly, peaks in detection did not occur during characteristic spring diatom blooms, but coincided with a winter bloom ofCoscinodiscus, suggesting that these bacteria likely influence distinct diatom host populations.We isolated multiple bacterial antagonists, spanning 4 classes and 10 bacterial orders. Notably, a diatom attaching RoseobacterPonticoccus alexandriiwas isolated multiple times, indicative of a persistent environmental presence. Moreover, many isolates had no prior reports of antagonistic activity towards diatoms. We verified diatom growth inhibitory effects of eight isolates. In all cases tested, these effects were activated by pre‐exposure to diatom organic matter. Discovery of widespread ‘cryptic’ antagonistic activity indicates that bacterial pathogenicity towards diatoms is more prevalent than previously recognised.Finally, examination of the global biogeography of WEC antagonists revealed co‐occurrence patterns with diatom host populations in marine waters globally.