研究了发光二极管(LED)单色光质对三角褐指藻细胞生长、岩藻黄素含量及岩藻黄素生物合成相关基因表达的影响。实验结果表明:红光、绿光、紫光可以促进三角褐指藻的生长,在红光处理下,第6天的藻细胞数与对照组相比极显著上升(P<0.01),增加了12.44%;黄光、蓝光对三角褐指藻的生长均有抑制作用;经绿光、紫光处理后,藻细胞的衰老速度比对照组快;用红光、紫光处理三角褐指藻,其岩藻黄素含量有所增加,与对照组相比分别增加了16.61%和26.78%;蓝光、绿光处理后的岩藻黄素含量与对照组相比极显著降低(P<0.01),这与光合作用相关的色素指标——叶绿素a的含量变化基本一致。岩藻黄素生物合成相关基因表达的结果表明:在玉米黄素环氧酶基因(zep)、八氢番茄红素合成酶基因(psy)、ξ-胡萝卜素脱氢酶基因(zds)、番茄红素β-环化酶基因(lcyb)、胡萝卜素异构酶基因(crtiso)和八氢番茄红素脱氢酶基因(pds)这6个基因中,关键基因psy的表达量与岩藻黄素含量的变化基本一致;在红光处理下,pds、lcyb的表达量显著上调。在不同光质处理下,三角褐指藻中岩藻黄素的生物合成可以由岩藻黄素生物合成相关基因表达来实现,而且还可能与光合作用有关。

The effects of LED monochromatic light quality of different colors on the growth of phaeodactylum tricornutum cells, their fucoxanthin content, and the expression levels of genes related to fucoxanthin biosynthesis are investigated. The results show that red light, green light, and purple light promote the growth of phaeodactylum tricornutum cells. In addition, the number of algal cells significantly increases by 12.44% on the 6th day under red light treatment (P<0.01) compared with that in the control group. Yellow light and blue light inhibit the growth of phaeodactylum tricornutum cells, and the aging rate of algal cells under green light and purple light treatments is higher than that in the control group. Compared with the control group, the fucoxanthin content of phaeodactylum tricornutum treated with red light and purple light increases by 16.61% and 26.78%, respectively, and that of phaeodactylum tricornutum treated with blue light and green light significantly reduces (P<0.01). The changes in chlorophyll and fucoxanthin content, which are related to photosynthesis, are basically the same under all treatments. Evaluation of the expression levels of genes related to fucoxanthin biosynthesis shows that among zeaxanthin cyclooxygenase gene (zep), phytoene synthase gene (psy), ξ-carotene dehydrogenase gene (zds), lycopene β-cyclase gene (lcyb), carotene isomerase gene (crtiso), and phytoene dehydrogenase gene (pds), the expression level of the key gene psy, is consistent with the change in the fucoxanthin content, whereas the expression levels of pds and lcyb are significantly upregulated under red light treatment. Therefore, fucoxanthin biosynthesis in phaeodactylum tricornutum under treatments with light quality of different colors is indicated by the expression levels of genes related to fucoxanthin biosynthesis, and it is possibly related to photosynthesis.