Classification Research Of Maroalgae Of Brown Algae And Green Algae From The Intertidal Zone Of Shandong Peninsula Based On DNA Barcoding Technology

Biological taxonomy and the research on evolutionare are always concerned,asaccurate identification is not only pursuited by taxonomists,but also be the importantpremise for carring out other scientific research in different areas.Classicalidentification is mainly based on morphological method,but morphology of species iseasily effected by many factors.With the development of molecular biology andsequencing technology, DNA barcoding technology is being used as a new means ofidentification of species,which is paied closely attention to increasingly.This paperfocus on identification Phaeophyta and Chlorophyta collected from shandongpeninsula, using both the method of morphology and DNA barcode technology.wealso focus on evolutionary relationships of Phaeophyta and Chlorophyta.We obtain81strains of brown algae collected in shandong peninsula,from March2012to October2013.The morphological identification are classified into20species,representing9orders,12families,16genera.Combining with molecularidentification,we identify24different species,representing10orders,13families,17genera.At the same time,we estimat performance of COI, ITS and LSU as DNAbarcoding markers for Phaeophyta.The results show that the amplification efficiencyof COI is highest in three genes.COI have good ability to distinguish the similarspecies.LSU is suitable for the, identification of genus or above level.A single genecan not fully identified species of brown algae, so we recommend the combination ofCOI and LSU gene is used to identify species.Although ability of ITS to distinguishspecies is similar with COI, some defects prevent ITS being used as a DNA barcodingmarker of brown algae.For example,it is difficult to obtain a single complete sequenceof ITS in the process of amplification, and the sequence is saturation which is notsuitable for constructing phylogenetic tree.Above all, we did not recommend usingITS genes for brown algae identification.In addition, we also focused on theevolutionary relationships of brown algae.We obtained125samples of Chlorophyta collected in the shandongpeninsula,from March2012to October2013.andin putian region,Fujianprovince,from April2013to May2013.113stains of Samples are identified by themorphological identification to27species,representing5orders,7families,8genera.The samples remained are identified to the orders, or families orgenera,owning to lacking of distinguished features.Combining with morphologicalidentification and DNA barcoding,we identified samples to29species, representing6orders,8families,13genera.At the same time,we estimated the performance of ITS,rbcL and tufA as DNA barcoding markers for Chlorophyta.tufA had good ability todistinguish the similar species; rbcL had the ability to distinguish species which are similar as the performance of tufA,but there is lower amplification efficiency for ITSthan that of rbcL. Compared with two other genes, amplification efficiency of ITS islowest.ITS had not the ability to distinguish the cluster of LPP (Ulva linza, Ulvaprocera and Ulva prolifera), and DNA barcoding gap of ITS is smallest in all threegenes.By analysis of phylogenetic relationship, we propose thatMonostroma,Protomonostroma, Capsosiphon and Urospora are classified intoUlotrichales, as well as Bryopsis and codium being classified into Bryopsidales.Gracilariopsis lemaneiformis is an economically important macroalgaeworldwide and the large-scale cultivation occur in south of China. Epiphytism inGracilariopsis lemaneiformis decreases the productivity and quality of G.lemaneiformis. In recent years, Ceramium epiphytism in Gracilariopsis lemaneiformisbreaks out. We find that Epiphytism in Gracilariopsis lemaneiformis occur mainly insummer and autumn,while it is not serious in winter and early spring. The result showthat the temperature is one of important factor that influence phenomenon ofEpiphytism.The epiphytes could penetrate into the host cortex tissue by rhizoid,affecting its growth and hence productivity. In addition, We focus on identification theepiphytes in Gracilariopsis lemaneiformis to the specie based on both morphologicaland molecular characters. The result show that epiphyte is Ceramium filicula bymorphological charaters. And rbcL sequence divergence between samples andCeramium filicula is0.9%, and the cluster of samples and Ceramium filicula isrobustly supported (BP=100%in NJ, and PP=1Bayesian analyses) in both ofphylogenetic trees.Ceramium filicula is the first reported in China. Therefore, wepresum that Ceramium filicula epiphytic in Gracilariopsis lemaneiformis is crypticspecies or a new kind of invasive species in China.