title: Quorum sensing of microalgae associated marine Ponticoccus sp. PD-2 and its algicidal function regulation.
abstract: Quorum sensing (QS) systems play important roles in regulating many physiological functions of microorganisms, such as biofilm formation, bioluminescence, and antibiotic production. One marine algicidal bacterium, Ponticoccus sp. PD-2, was isolated from the microalga Prorocentrum donghaiense, and its N-acyl-homoserine lactone (AHL)-mediated QS system was verified. In this study, we analyzed the AHLs profile of strain PD-2. Two AHLs, 3-oxo-C8-HSL and 3-oxo-C10-HSL, were detected using a biosensor overlay assay and GC-MS methods. Two complete AHL-QS systems (designated zlaI/R and zlbI/R) were identified in the genome of strain PD-2. When expressed in Escherichia coli, both zlaI and zlbI genes could each produce 3-oxo-C8-HSL and 3-oxo-C10-HSL. Algicidal activity was investigated by evaluating the inhibitory rate (IR) of microalgae growth by measuring the fluorescence of viable cells. We found that the metabolites of strain PD-2 had algicidal activity against its host P. donghaiense (IR 84.81%) and two other red tide microalgae, Phaeocystis globosa (IR 78.91%) and Alexandrium tamarense (IR 67.14%). β-cyclodextrin which binds to AHLs and inhibits the QS system reduced the algicidal activity more than 50%. This indicates that inhibiting the QS system may affect the algicidal metabolites production of strain PD-2. Our study indicated that a QS-regulated algicidal system may play a potential role in the process of red tides disintegration. QS might be a potential way to control red tides.
authors.affiliation: Key Laboratory for Marine Bioactive Substances and Modern Analytical Technology of the First Institute of Oceanography, State Oceanic Administration, No. 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China.
authors.forename: Wendan
authors.initials: W
authors.lastname: Chi
authors.affiliation: Key Laboratory for Marine Bioactive Substances and Modern Analytical Technology of the First Institute of Oceanography, State Oceanic Administration, No. 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China. zhengli@fio.org.cn.|Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, People's Republic of China. zhengli@fio.org.cn.
authors.forename: Li
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Key Laboratory for Marine Bioactive Substances and Modern Analytical Technology of the First Institute of Oceanography, State Oceanic Administration, No. 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China.
authors.forename: Changfei
authors.initials: C
authors.lastname: He
authors.affiliation: Key Laboratory for Marine Bioactive Substances and Modern Analytical Technology of the First Institute of Oceanography, State Oceanic Administration, No. 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Han
authors.affiliation: Key Laboratory for Marine Bioactive Substances and Modern Analytical Technology of the First Institute of Oceanography, State Oceanic Administration, No. 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China.
authors.forename: Minggang
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Key Laboratory for Marine Bioactive Substances and Modern Analytical Technology of the First Institute of Oceanography, State Oceanic Administration, No. 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Gao
authors.affiliation: Key Laboratory for Marine Bioactive Substances and Modern Analytical Technology of the First Institute of Oceanography, State Oceanic Administration, No. 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China.|Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266071, People's Republic of China.
authors.forename: Chengjun
authors.initials: C
authors.lastname: Sun
authors.affiliation: School of Life Science of Yantai University, Yantai, 264000, People's Republic of China.
authors.forename: Gefei
authors.initials: G
authors.lastname: Zhou
authors.affiliation: National Deep Sea Center, State Oceanic Administration of China, Qingdao, 266237, People's Republic of China.
authors.forename: Xiangxing
authors.initials: X
authors.lastname: Gao
keywords: AHLs; Algicidal activity; Microalgae-associated bacteria; Quorum sensing; β-Cyclodextrin