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General Session 3: Biological oceanography & global change |
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Identification, characterization and phosphate depleted-inducible expression of PhoAaty-type alkaline phosphatase of Emiliania huxleyi
GS3-29-S
Tangcheng Li* , State Key Laboratory of Marine Environmental Science
Chentao Guo, State Key Laboratory of Marine Environmental Science
Xin Lin, State Key Laboratory of Marine Environmental Science
Yaqun Zhang, State Key Laboratory of Marine Environmental Science
Cong Wang, State Key Laboratory of Marine Environmental Science
Seijie Lin, State Key Laboratory of Marine Environmental Science
Presenter Email: 820195402@qq.com
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| Emiliania huxleyi, the cosmopolitan distributed coccolithophore in the modern ocean, plays important role in the carbon cycle and local climate while they form extensive bloom in both coastal and open ocean. It has been well known as oligotrophic species and is able to express a type of alkaline phosphatase (EHAP) under phosphorus-limited condition. Alkaline phosphatase (AP) which is an essential enzyme expression by phytoplankton to utilize dissolved organic phosphorus (DOP) when dissolved inorganic phosphate (DIP) is scarce in the ocean. In this study, we identified an atypical type AP gene (eh-phoAaty) of Emiliania huxleyi different to EHAP. Both the gene transcript and protein expression of eh-phoAaty were examined of Ehux cells from P-depleted and P-replete cultures. Our results showed that both the gene transcripts and protein expression of eh-phoAaty were up-regulated in the P-depleted cultures. Furthermore, genetic sequence analysis and RT-qPCR data revealed distinct dynamic expression pattern between ehap and eh-phoAaty, whilst the expression of both types AP was induced by ambient DIP deficiency. the two protein all correlate with AP activity indicating E.huxleyi is able to expression both APs to copy with P deficiency. We also found Ca2+ was responsible to AP (include intracellular and membrane-associated enzymes) activities rather than Zn2+, which implies that the distinct metal ions used by phytoplankton cell enzymes can endow with growth advantages in the marine environment which is considered to be Zn-limited. Keywords: Emiliania huxleyi, alkaline phosphatase, gene expression, phosphorus limitation, cofactor |
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