Cyanobacteria Phosphatase Gene Diversity And Its Response To Phosphorus

The rapid development of economy leading to the eutrophication in many water ecosystems, and threatens to the environment and people health arounding there.Alkaline phosphatase(APase) is yet known the predominate DOP hydrolase,the phosphate released by APase are utilized by cyanobacteria, which lead to the quick growth and reprouction of algae cells.In this research project,firstly, we selected 34 kinds of cyanobacterial species that deposited in Chinese Freshwater Algae Culture Collection to survey the Apase types that containing in these strains. Secondly, we studied the diversity of cyanobacteria that distributed in five sites of the Pearl River by taking cyanobacterial pho X and 16 S r RNA Gene as target for the high-throughput sequencing. Finally, we studied the growth, Apase ability, and pho expression of Anabaena flos-aquae FACHB245 in inorganic phosphorus and organic phosphorus medium.The main conclusions are as follows: 1) The survey of alkaline phosphatase gene in 34 kinds of cyanobacteria shows that every strain has one alkaline phosphatase gene at least. among these strain, Aulosira FACHB-601 and Anabaena cylindrica FACHB-170 have three kinds of alkaline phosphatase genes: pho X, pho D and pho A. 25 OTU of 34 have pho X, 7 OTU of 34 OTU of 34 have pho A and 12 OTU of 34 have pho D. It is obvious that the diversity of pho X is higher than other two, which also conluded the pho X plays an important role in phosphorus cycle. 2) Water samples were collected from Zhongda(ZD), Tanwei(TW), Baixianke(BXK), Nansha(NS) and Suishi(SS) sites. The high-throughput sequencing of cya16 S r RNA gene shows that we got 11845 available sequences from 5 samples, and contained 74, 66, 72, 90, 72 operational taxonomy unit(OTU) respectively. The Simpson Index and Shannon Index suggested the NS site has the highest cyanobacteria diversity, while the TW site has the lowest. 3) The high-throughput sequence of alkaline phosphatases pho X shows that 10489 available sequence were obtained, and contain 185,205,144,202,210 OTUs in ZD, TW, BXK, NS, and SS, respectively. The Simpson Index and Shannon Index suggested the NS andTW site has the highest cyanobacteria diversity, while the BXK site has the lowest. 4) Growth, Apase ability, and pho expression of Anabaena flos-aquae FACHB245 in inorganic phosphorus and organic phosphorus medium were studied. Results suggested the activity of alkaline phosphatase of FACHB245 cultured in inorganic phosphorus medium is 0.7±0.22mmol/min/OD600 nm, which is lower than FACHB245 cultured in phosphorus free and organic phosphorus media. As for the expression of alkaline phosphatase genes, pho D and pho X increase significantly during cultured in phosphorus free and organic phosphorus media. The result shows that Anabaena flos-aquae FACHB245 increases the activity of alkaline phosphatase to deal with the stress of phosphorus deficiency.