Studies On Growth Characteristic And Phylogenetic Region Of Chattonella Marina Isolated From Daya Bay, The South China Sea

Chattonella marina is known to be one of the most noxious red tide organisms, and itsblooms have caused great damages to cultured fish and shellfish in Japan, Canada, Australia andother countries. Blooms of C. marina have increasingly occurred in Chinese coasts including inSouth China Sea, Yellow Sea and Bo Hai Sea, and its blooms are becoming a potential threat toChinese coastal environments and mariculture. In this thesis, the growth characteristic of thelocal strain of C. marina isolated from Daya Bay, the South China Sea and its phylogeneticregion were studied.The growth of C. marina was significantly inhibited by nutrient restriction, especially by Nlimitation. This alga cell can utilize several kinds of DON such as Urea, glycin, L-threonine, 1,4-tetramethylene-diamine hydrochloride and DOP such as ATP and G-P. However, L-alanineand G-6-P inhibited the growth of the alga cells. The strain of C. marina maintained possitivegrowth over 18℃, and optimal growth was observed at 25℃, which indicates the hightemperature adaption of this species. C. marina was preponderant in co-culture as the inoculationproportions of C. marina and S. trochoidea (C: S) was 1:1 and 3:1. However, S. trochoideadominated in co-culture as C: S=1:3. On the other hand, S. costatum held the dominance as itsinitial cell numbers were over or equal to those of C. marina (C: SK was 1:1 and 1:6). C. marinawon the competition in the co-culture system only when its initial cell number was six times thanthat of S. costatum (C: SK=6:1). The filtrate of C. marina showed inhibiting effect on the growthof S. costatum and itself, but no inhibition on S. trochoidea.Internal Transcribed Spacer (ITS) sequence of C. marina was analyzed using single cellPCR amplification. The ITS sequence of this strain was compared and discussed with otherstrains of genus Chattonella and other species in order haptophyta obtained from Gene Bank, andthe phylogenetic trees were constructed. The ITS sequence of C. marina isolated from Daya Baydisplayed very high level of similarity with the strain from Japanese sea waters, which indicatedthat the local strain was most likely originated from Japanese sea regions.