A Population Genetics Research Of Turbinaria Peltata In The Northern South China Sea

With the rapid degradation of coral reefs due to global warming and anthropogenic impacts,relatively high-latitude areas,such as the northern South China Sea(SCS),are likely to become refuges for tropical coral species.To explore potential adaptability mechanisms of relatively high-latitude scleractinian corals and its high temperature tolerance as a result of climate change,we investigated one scleractinian coral species,Turbinaria peltata,in the northern SCS,and researched a total of 81 samples from 5 sites.In this study,six following main results are presented:(1)The species-specific microsatellite markers of T.peltata can be efficiently developed by meta-transcriptomic sequencing.Here we we firstly developed 449 microsatellite markers of T.peltata and got 10 markers for population genetic research.The genetic research system of complete resolution was formed based on ten microsatellite markers,one nuclear gene(internal transcribed spacer,ITS),and one mitochondrial gene(mitochondrial cytochrome oxidase subunit I gene,mt DNA COI).(2)The results of microsatellite markers indicated that the genetic diversity of T.peltata in the northern SCS is low,indicating that T.peltata has insufficient genetic adaptability.A significantly moderate genetic differentiation was observed among T.peltata populations.The Mantel test results showed that this genetic differentiation was strongly correlated with the average sea surface temperature(SST)and geographical distance,suggesting the genetic structure of T.peltata in the relatively high-latitude of the SCS was significantly affected by average SST and geographical isolation.(3)The results based on ITS and mt DNA COI both indicated the low genetic diversity of T.peltata.The ITS results revealed a moderate genetic differentiation,which was strongly correlated with geographical distance.(4)The Dongfang(DF)population near a fishing port was exposed to severe anthropogenic environmental stress,which may drive its extraordinarily special genetic features(the lowest genetic diversity and high genetic differentiation).DF population may be a risk of local extinction in the future.(5)The high temperature stress experiment results suggest the high temperature tolerance of Wei Zhou(WZ)Island may be higher than Daya Bay(DY),and they may have the same high temperature response mechanism.(6)To resist future climate change,the genetic adaptability of T.peltata in the relatively high-latitude of the SCS is insufficient,and this ecosystem may be susceptible.Corresponding conservation measures should be taken according to its genetic characteristics,such as the decreased genetic diversity and limited gene flow.