Resource Evaluation Of Scleratinia In Yangmeikeng Sea Area Of Shenzhen

In recent years,the Shenzhen sea area has suffered frequent typhoon disasters,which have had a certain impact on the distribution of coral reefs.Therefore,it is necessary to re-investigate the distribution of coral reefs in the Daya Bay.On the other hand,Dapeng New Area is transforming from the old industrial zone to the biological industry.However,there may still be residual heavy industrial waste in the environment,which could potentially affect the already fragile coral reefs.Therefore,to explore the tolerance of coral under Cu²⁺and the expression of genes under stress conditions.It is of great significance to reveal the regulation of coral metabolic pathway and the molecular mechanism during stress.In particular,heavy metal pollutants have the characteristics of long residue time and easy enrichment.Therefore,it is of great significance to explore the tolerance of coral under Cu²⁺and the expression of genes under stress conditions,to reveal the regulation of coral metabolic pathway and the molecular mechanism during stress.Our research was used belt transect method to investigate the composition,distribution and diversity of reef-building corals in the Yangmeikeng sea area of Shenzhen in Nov.2017.Symbiotic algae of 47 reef coral samples from 20 species were classified and their genetic diversity was analyzed by Neighbor-Joining clustering tree witch was constructed based on ITS sequence.Goniopora minor was exposed to the different concentrations of Cu²⁺stress.Five groups were set up in the stress experiment?0?g/L,25?g/L,50?g/L,75?g/L,90?g/L?.The effects of Cu²⁺stress on Goniopora minor were studied by observing and recording the apparent state of corals,counting the density of symbiotic algae,concentration of the changes of chlorophyll-a,enzyme activity and relative expression of genes in corals.The main results are as follows:1.Distribution and diversity of reef-building corals in Yangmeikeng waters,ShenzhenA total of 22 species belonging to 14 genera and 6 families were recorded in this survey.The most important value in this sea area is Favia favus.The top three dominant species in this area are Favia favus,Platygyra yaeyamaensis and Favia speciosa.Diversity index was 2.396,evenness index was 0.537,richness index was 3.371 and dominance index was 0.865.The biological complexity and stability of coral community are higher than those of other sea areas in Shenzhen,which has great ecological protection value.2.Analysis of symbiotic algae flora in coral symbiotic system based on ITS sequence20 of reef-building coral symbiotic algae in the Yangmeikeng sea area belong to two different species?subgroup?.19 samples belonged to symbiotic algae of C1 subgroup.One sample belonged to symbiotic algae of C15 subgroup.The genetic distance between the two subpopulations was 0.01.By comparing ITS sequences obtained in Yangmeikeng sea area,the content of?A+T?in all samples was less than?G+C?,which showed a certain CG bias.3.Effects of Cu²⁺Stress on CoralsCu²⁺stress had significant effects on the density and chlorophyll a content of Goniopora minor per unit area?p<0.05?.Under Cu²⁺stress,the density and chlorophyll a concentration of Goniopora minor showed a downward trend,and increased in the downward range.T-SOD activity,CAT activity and the concentration of H₂O₂ in the tissues of corals with Goniopora minor all showed one or two peaks at the beginning of stress,but slowly decreased to the pre-stress level with the prolongation of stress time.With the increase of Cu²⁺concentration,the expression of ZNFX1 gene and HSP70 gene decreased gradually,and the difference between groups was very significant?p<0.01?.The expression of ITGB1 gene and PPAP28 gene increased gradually,with significant difference between groups?p<0.01?.Cu-ZnSOD gene increased as a whole,the difference between groups was very significant?p<0.01?.And reached the valley value at 25?g/L.The expression of SLC34A2 gene increased in general,with significant difference between groups?p<0.01?,reaching the peak at 50?g/L.