Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
Appl Environ Microbiol. 2023 Feb 28;89(2):e0211122. doi: 10.1128/aem.02111-22. Epub 2023 Jan 23.
Microcystis aeruginosa is predicted to interact and coexist with diverse broad- and narrow-host-range viruses within a bloom; however, little is known about their affects on population dynamics. Here, we developed a real-time PCR assay for the quantification of these viruses that have different host ranges. During the sampling period, total abundance showed two peaks in May and August with a temporary decrease in June. The population is largely divided into three phylotypes based on internal transcribed sequences (ITS; ITS types I to III). ITS I was the dominant phylotype (66% to 88%) except in June. Although the ITS II and III phylotypes were mostly less abundant, these phylotypes temporarily increased to approximately equivalent abundances of the ITS I population in June. During the same sampling period, the abundances of the broad-host-range virus MVGF_NODE331 increased from April to May and from July to October with a temporary decrease in June, in which its dynamics were in proportion to the increase of total abundances regardless of changes in host ITS population composition. In contrast, the narrow-host-range viruses MVG_NODE620 and Ma-LMM01 were considerably less abundant than the broad-host-range virus and generally did not fluctuate in the environment. Considering that could increase the abundance and sustain the bloom under the prevalence of the broad-host-range virus, host abundant and diverse antiviral mechanisms might contribute to coexistence with its viruses. The bloom-forming toxic cyanobacterium Microcystis aeruginosa interacts with diverse broad- and narrow-host-range viruses. However, the dynamics of the population (at the intraspecies level) and viruses with different host ranges remain unknown. Our real-time PCR assays unveiled that the broad-host-range virus gradually increased in abundance over the sampling period, in proportion to the increase in total abundance regardless of changes in genotypic composition. The narrow-host-range viruses were considerably less abundant than the broad-host-range virus and did not generally fluctuate in the environment. The expansion and maintenance of the bloom even under the increased infection by the broad-host-range virus suggested that highly abundant and diverse antiviral mechanisms allowed them to coexist with viruses under selective pressure. This paper expands our knowledge about the ecological dynamics of viruses and provides potential insights into their coexistence with their host.
铜绿微囊藻预计会与水华期内多样的广宿主和窄宿主范围的病毒相互作用和共存；然而，人们对它们对种群动态的影响知之甚少。在这里，我们开发了一种实时 PCR 检测方法来定量分析这些具有不同宿主范围的病毒。在采样期间，总丰度在 5 月和 8 月出现两个峰值，6 月暂时下降。种群主要分为基于内部转录序列（ITS；ITS 类型 I 到 III）的三个宗谱型。除 6 月外，ITS I 是主要的宗谱型（占 66%至 88%）。尽管 ITS II 和 III 宗谱型的丰度较低，但这些宗谱型在 6 月暂时增加到与 ITS I 种群相当的丰度。在同一采样期间，广宿主范围病毒 MVGF_NODE331 的丰度从 4 月到 5 月和从 7 月到 10 月增加，6 月暂时下降，其动态与总丰度的增加成正比，而与宿主 ITS 种群组成的变化无关。相比之下，窄宿主范围的病毒 MVG_NODE620 和 Ma-LMM01 的丰度明显低于广宿主范围的病毒，通常在环境中没有波动。考虑到在广宿主范围病毒流行的情况下， 可以增加丰度并维持水华，丰富多样的抗病毒机制可能有助于与病毒共存。 形成水华的有毒蓝藻铜绿微囊藻与多种广宿主范围和窄宿主范围的病毒相互作用。然而，不同宿主范围的种群（种内水平）和病毒的动态仍然未知。我们的实时 PCR 检测结果表明，广宿主范围的病毒在采样期间逐渐增加丰度，与总丰度的增加成正比，而与基因型组成的变化无关。窄宿主范围的病毒丰度明显低于广宿主范围的病毒，通常在环境中没有波动。即使在广宿主范围病毒感染增加的情况下， 的扩展和维持表明高度丰富多样的抗病毒机制使它们能够在选择压力下与病毒共存。本文扩展了我们对 病毒生态动态的认识，并为它们与宿主共存提供了潜在的见解。
