Cyanobacteria are distributed globally in the sea, fresh water, and land. Akinetes (dormant cells) of cyanobacteria are highly resistant to dry conditions, contributing to the survival of terrestrial cyanobacteria. However, the substances that regulate akinete dormancy and germination have not been elucidated. The present study investigated the effects of the phytohormone cytokinin (CK), on the germination stage of a terrestrial filamentous cyanobacterium, Nostoc sp. HK-01. In the cell suspensions of Nostoc sp. HK-01, isopentenyladenine (iP), isopentenyladenosine (iPR), cis-zeatin (cZ), cis-zeatinriboside (cZR), trans-zeatin (tZ), and a trace amount of trans-zeatinriboside (tZR) were identified, according to their retention times and multiple reaction monitoring (MRM) transitions, using high performance liquid chromatography and electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Product ion scans also identified iP, iPR, cZ, and cZR. The present study established an isolation method for the dormant Nostoc akinetes, and then treated them with CKs. iP and tZ promoted the germination of akinetes, while cZ did not. S-4893, which is a CK antagonist, inhibited germination and the promotive activity of the applied iP. The results strongly suggest that cyanobacteria have a very similar perception system to plants, and that they regulate the dormancy and germination of their own cells and/or other cells via CKs. The production of CKs by several species of cyanobacteria was previously reported. However, this is the first investigation showing the role of phytohormones in the dormant cell physiology of cyanobacteria.

中文翻译：

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细胞分裂素影响陆生丝状蓝细菌 Nostoc sp. 的动子萌发阶段。HK-01

蓝藻在全球范围内分布在海洋、淡水和陆地中。蓝藻的 Akinetes（休眠细胞）对干燥条件具有很强的抵抗力，有助于陆生蓝藻的存活。然而，调节动植物休眠和萌发的物质尚未阐明。本研究调查了植物激素细胞分裂素 (CK) 对陆生丝状蓝藻 Nostoc sp. 萌发阶段的影响。HK-01。在 Nostoc sp 的细胞悬浮液中。HK-01、异戊烯基腺嘌呤 (iP)、异戊烯基腺苷 (iPR)、顺式玉米素 (cZ)、顺式玉米素核苷 (cZR)、反式玉米素 (tZ) 和微量反式玉米素核苷 (tZR) 被鉴定出来，根据保留时间和多反应监测 (MRM) 转换，使用高效液相色谱法和电喷雾电离串联质谱法 (HPLC-ESI-MS/MS)。子离子扫描还鉴定了 iP、iPR、cZ 和 cZR。本研究建立了休眠的发菜动植物的分离方法，然后用 CKs 对其进行处理。iP 和 tZ 促进了动植物的萌发，而 cZ 则没有。S-4893 是一种 CK 拮抗剂，可抑制所应用的 iP 的萌发和促进活性。结果强烈表明蓝藻具有与植物非常相似的感知系统，并且它们通过 CK 调节自身细胞和/或其他细胞的休眠和萌发。先前报道了几种蓝藻产生 CKs。然而，这是第一次显示植物激素在蓝藻休眠细胞生理学中的作用的研究。