Identification of Chlorella Spp. Isolates Using Ribosomal DNA Sequences

利用核糖體核酸序列鑑定小球藻之分離株

吳宣霖(Hsiuan-Lin Wu) ； 許瑞祥(Ruey-Shyang Hseu) ； 林良平(Liang-Ping Lin)

《Botanical Bulletin of Academia Sinica》 42卷2期 (2001/04) Pp. 115-121

https://doi.org/10.7016/BBAS.200104.0115

摘要

小球藻Chlorella spp.為目前被廣泛應用的微藻之一，由於Chlorella spp.為構造簡單之單細胞藻類，作為種鑑定依據的形態特徵常因生態環境改變而異，造成鑑定上的困難。為瞭解Chlorella spp.種間的親緣關係，本研究以分子生物技術中的聚合連鎖反應放大特定區域，分析四株分別從台灣和印尼所分離之小球藻細胞核，及葉錄體內的核糖體之小次體基因序列，與基因資料庫已發表的基因序列加以比對，以進行小球藻屬藻株Chlorella spp.的分類鑑定，并與保存中心藻種，比較分類結果互相驗證。結果顯示供試的四株小球藻均接近於常見的綠藻Chlorella sorkiniana，此為一可生長於35℃水域中的耐高溫水球藻，分析結果更顯示藻株216更接近於藻株21和I。葉綠體SSU rDNA基因序列比細胞核者更清楚的分析出四株小球藻的親緣關係。藻株21與216跟藻株I較為接近。從形態與生化性質比較驗證後，顯示此rDNA分類結果與傳統分類方法所得結果，呈強烈的相關性。

關鍵字

小球藻 ； 核糖體之小次體 ； 細胞核 ； 葉綠體 ； 聚合酶連鎖反應 ； 系統發生學

並列摘要

Members of the Chlorella species are very simple unicellular algae, easy to cultivate and widely used in various physiological studies. Their morphological and physiological characteristics, however, normally change with the environment, making species identification difficult. To elucidate the relationship between various strains of Chlorella, this investigation analyzed the nuclear-encoded and chloroplast-encoded small-subunit rDNA sequences of four strains of Chlorella using PCR techniques. These strains were isolated from different rivers and ponds in Taiwan and Indonesia, and then compared and identified using stock strains of Chlorella spp. from the culture collection centers, and published DNA sequence data from Genbank. Experimental results attributed the isolated strains mainly to C. sorokiniana, a common species of green algae which grows in freshwater ecosystems at around 36°C. In addition, phylogenetic analysis of nuclear-encoded and chloroplast-encoded small-subunit rDNA sequences from spherical green algae of the genera Chlorella revealed the sequences to closely resemble each other. Further analyses indicated that Chlorella spp. 216 was close to Chlorella spp. 21 and I. Generally, the chloroplast data sets supported the lineages more than the nuclear data sets did. Strains 21 and 216 were closer to I. Comparisons with some of the morphological and biochemical data indicated that the phylogenetic analysis of rDNA sequences was in line with results obtained by conventional methods.

並列關鍵字

Chlorella ； Chloroplast ； Nuclear ； PCR ； Phylogeny ； Small subunit.