National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou 325035, China; Zhejiang Provincial Key Lab for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China.
National and Local Joint Engineering Research Center of Ecological Treatment Technology for Urban Water Pollution, Wenzhou University, Wenzhou 325035, China; Zhejiang Provincial Key Lab for Subtropical Water Environment and Marine Biological Resources Protection, Wenzhou University, Wenzhou 325035, China.
Ecotoxicol Environ Saf. 2023 Sep 15;263:115369. doi: 10.1016/j.ecoenv.2023.115369. Epub 2023 Aug 14.
Free-living Symbiodinium, which forms symbiotic relationships with many marine invertebrates, plays an important role in the vast ocean. Nutrient levels have been shown to significantly impact microbial community structure and regulate algal communities. In this study, the bacterial community structure within the phycosphere of free-living Symbiodinium underwent significant changes in response to nutrient stimulation. Alteromonas exhibited dominance in Zobell 2216E broth nutrient stimulation concomitant with the demise of algal cells. Alteromonas abrolhosensis JY-JZ1, a marine bacterium isolated from the phycosphere of Symbiodinium, demonstrated an algicidal effect on Symbiodinium cells. Optical and scanning electron microscopy revealed that the algal cell membrane structure was disrupted, leading to intracellular leakage. Strain JY-JZ1 exerted its cytotoxicity by producing and secreting bioactive compounds into the supernatant. The marked declines in the chlorophyll a content, photosynthetic efficiency (Fv/Fm) and the electron transport rate (rETR) indicated that the photosynthetic system of Symbiodinium was damaged by JY-JZ1 supernatant. The observed elevation in levels of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) content suggested that the algal cells experienced oxidative stress. Moreover, the supernatant exhibited remarkable adaptability to temperature and pH. Additionally, it displayed exceptional algicidal efficacy against various harmful algae species. To the best of our knowledge, this study represents the first successful isolation of an algicidal bacterial strain from the phycosphere of free-living Symbiodinium and subsequent investigation into its mechanism for controlling Symbiodinium growth, thereby providing novel insights into algae-bacteria interactions. The remarkable algicidal efficacy exhibited by strain JY-JZ1 against other harmful algae species suggests its significant potential for harmful algal blooms (HABs) control.
自由生活的共生藻与许多海洋无脊椎动物形成共生关系，在广阔的海洋中发挥着重要作用。研究表明，营养水平会显著影响微生物群落结构，并调节藻类群落。在这项研究中，自由生活的共生藻的藻际细菌群落结构对营养刺激做出了显著变化。在 Zobell 2216E 肉汤营养刺激下，交替单胞菌表现出优势，同时藻类细胞死亡。从共生藻藻际分离得到的海洋细菌——Abrolhosensis JY-JZ1 对共生藻细胞具有杀藻作用。光学和扫描电子显微镜显示，藻细胞膜结构被破坏，导致细胞内渗漏。菌株 JY-JZ1 通过将生物活性化合物分泌到上清液中发挥细胞毒性。叶绿素 a 含量、光合作用效率（Fv/Fm）和电子传递率（rETR）显著下降表明，JY-JZ1 上清液破坏了共生藻的光合作用系统。丙二醛（MDA）、谷胱甘肽（GSH）、超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）含量的升高表明，藻细胞受到氧化应激。此外，上清液对温度和 pH 值具有显著的适应性。此外，它对各种有害藻类表现出卓越的杀藻效果。据我们所知，这项研究首次成功地从自由生活的共生藻的藻际分离出一种杀藻细菌菌株，并对其控制共生藻生长的机制进行了研究，从而为藻类-细菌相互作用提供了新的见解。菌株 JY-JZ1 对其他有害藻类表现出显著的杀藻效果，表明其在控制有害藻华方面具有重要潜力。
