缺氮胁迫下雨生红球藻虾青素积累过程中的基因组MSAP分析

Genome MSAP analysis of Haematococcus pluvialis astaxanthin accumulation under nitrogen depletion stress

关键词:  藻类学, 缺氮胁迫, 雨生红球藻, 虾青素, 甲基化变化

Key words:  phycology, nitrogen depletion stress, Haematococcus pluvialis, astaxanthin, methylation change

摘要:

虾青素具有多种生物学活性,雨生红球藻为天然虾青素的最佳来源,缺氮胁迫会导致雨生红球藻积累虾青素。为了解缺氮条件下雨生红球藻虾青素积累的分子机制,该研究通过对雨生红球藻进行缺氮胁迫,结合MSAP法,研究了雨生红球藻在缺氮胁迫下虾青素积累过程中基因组甲基化水平的变化,结果表明:缺氮胁迫0～72 h期间,雨生红球藻生长速度减慢,而虾青素积累主要发生在缺氮处理12～24 h期间,随后积累速度减慢。同时,对缺氮胁迫0、24、72 h的雨生红球藻基因组DNA进行甲基化敏感扩增多态性分析,共得到了291个甲基化多态性位点,其中发生甲基化变化的位点在0～24 h和24～72 h分别占总位点的29.90%和53.95%。在缺氮胁迫24 h处DNA半甲基化率最大(为12.71%),全甲基化率最低(为26.80%); 缺氮胁迫72 h处DNA全甲基化率最高(为28.52%),半甲基化率最低(为1.72%)。这表明DNA甲基化调节方式的改变是虾青素积累过程中的一种重要调控模式。

Abstract:

Haematococcus pluvialis is the best resource for natural astaxanthin, which has multiple biological functions. Nitrogen depletion can result in astaxanthin accumulation in H. pluvialis. In order to explore the molecular mechanism of astaxanthin accumulation in H. pluvialis under nitrogen depletion stress, the growth rate of the algae was found to decrease during 0-72 h, the accumulation of astaxanthin mainly occured during 12-24 h, and then slowed down. MSAP analysis of stress time point at 0, 24 and 72 h got 291 methylation polymorphism loci, among which 29.90% of 0-24 h methylation loci and 53.95% of 24-72 h methylation loci changed. After 24 h of nitrogen depletion stress, the DNA semi-methylation rate was the highest(12.71%), and the full-methylation rate got the lowest(26.80%). On the contrary, full-methylation rate was the highest(28.52%)and the semi-methylation rate was the lowest(1.72%)after 72 h stress. DNA methylation changes appeared to be a vital regulation for astaxanthin accumulation.