海洋细菌Marinobacter adhaerens HY-3分离鉴定及对中肋骨条藻的化感作用

菌藻化感作用是一种极其复杂的生理、生态学现象.从虾蟹混养池分离得到1株海洋细菌,经16S rRNA序列比对确定为Marinobacter adhaerens HY-3,选择我国常见赤潮优势种中肋骨条藻(Skeletonema costatum)作为对象,研究海洋细菌与其种间化感效应,利用共培养和添加细菌胞外代谢物,以S.costatum生长量及叶绿素a含量为参数,研究细菌对S.costatum生长及光合作用的影响.结果表明,菌液浓度104以上对S.costatum生长产生抑制,培养至第10 d,104、106、108组藻生长量分别是对照组的70%、23%、22%;叶绿素合成量是对照组88%、62%、60%;抑制效应随菌浓度的增加有逐渐增加的趋势.添加细菌胞外代谢物,对S.costatum生长无影响;因此,M.adhaerens HY-3对S.costatum存在一定的化感作用,对其生长及光合作用均产生较大的影响;S.costatum与M.adhaerens HY-3的种间相互作用,是由菌藻细胞的直接接触进行,代谢物不存在化感作用因子.

Isolation and Identification of Marinobacter adhaerens HY-3 and Its Allelopathy on Skeletonema costatum

The allelopathy between bacteria and algae is a very complicated physical and ecological phenomenon. A marine bacterium was isolated from the water of a shrimp and crab mix-culturing pond. By 16S rRNA analysis, it was identified as Marinobacter adhaerens HY-3.Skeletonema costatum, a common dominant species of red-tide microorganism in China, was chosen as the other research object. The allelopathic effect of Marinobacter adhaerens HY-3 on S. costatum was studied. Using the growth mass of Skeletonema costatum and the content of chlorophyll a as the parameters, the effects of HY-3 on the growth and photosynthesis of Skeletonema costatum were studied after co-cultivation and addition of extracellular metabolites of HY-3.The results showed that the growth of S. costatum was inhibited when the concentration of the strain HY-3 was above 10⁴, and the growth mass of the 10⁴, 10⁶ and 10⁸ HY-3 group was 70%, 23% and 22% of the control group respectively on the 10^th day, with the content of chlorophyll being 88%, 62% and 60% of the control group, respectively. Therefore, the suppression increased with increasing concentration of HY-3.However, addition of extracellular metabolites of HY-3 had no effect on the growth of S. costatum. Conclusions: M. adhaerens HY-3 had certain allelopathy on S. costatum and affected its growth and photosynthesis. Moreover, interaction between M. adhaerens HY-3 and S. costatum was achieved by their direct contact and the extracellular metabolites did not contain allelopathy factors.