Generation Analysis Of Enteromorpha Prolifera And Gene Analysis Of Macro Marine Algae

Enteromorpha prolifera is distributed worldwide and predominantly composition of"green tides", which attract extensive attention because of their ecological and economic impacts. In this paper, different samples from different collecting locations are detected whether they are sporophytes or gametophytes. Subsequently effect of ecological factors including water temperature, salinity, light-intensity on sporophytes and gametophytes has been studied. The sequences of ITS, rbcL gene and 18S rRNA gene of different samples from different collecting locations have been analyzed. The result turned out that 20 samples collected in the spring of 2009 are gametophytes, accounting for 87.0%, while 3 samples are sporophytes, accounting for 13.0%. Half of 4 samples collected in the autumn of 2009 are sporophytes, accounting for 50.0%, and the other half are mixture of gametophytes and sporophytes. Sporophytes and gametophytes respond differently under different levels of ecological factors. Gametophytes can dramatically be stimulated under higher temperature (25℃) and lower salinity (10‰) to release gametes, while sporophytes can significantly be stimulated under higher temperature (25℃) and higher salinity (40‰) to release zoospores. The variation rate of ITS, rbcL gene and 18S rRNA gene of Enteromorpha prolifera samples are different. The sequences of 18S rRNA gene are more conservative, while the ITS sequences can provide abundant variable sites.Although DNA barcoding has played an important role in the identification of numerous marine animals, there is still no unified standard for marine algae. Thus the analysis of variation rate of standard DNA sequences is the key to DNA barcoding project of marine algae. This paper is based on achievements in marine algae during recent years and investigate further on the UPA(universal plastid amplicon), coxⅠ(cytochrome c oxidase subunit 1) gene, rbcL(large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase) gene and ITS(nuclear ribosomal DNA internal transcribed spacers). The primers used to amplify UPA and coxⅠare highly universal, with amplification efficiency scoring 52.6% and 44.7% respectively. Different combinations of primers aiming at different types of marine algae are used to amplify ITS and rbcL gene, with amplification efficiency scoring 50% and 58.3% respectively. The variation rate of coxⅠgene is highest (interspecific genetic distance is 0.083~0.385), followed by ITS(interspecific genetic distance is 0.001~0.319) and UPA(interspecific genetic distance is 0.001～0.154). The sequences of rbcL gene are most conservative. Based on three evaluation methods including BLAST-Based Method, Distance-Based Method and Tree-Based Method, it can be concluded that ITS and UPA are better candidates for DNA corcoding applied in macro algae.