为研究三角褐指藻(Phaeodactylum tricornutum)光合作用生理指标与岩藻黄素含量之间的相关性,采用不同的发光二极管单色光质对三角褐指藻进行处理,测定岩藻黄素含量、光合作用相关生理参数和相关基因表达,并研究测定指标之间的相关性。研究结果表明:紫光可极显著地提高三角褐指藻岩藻黄素和叶绿素a的含量(P<0.01)。光合生理指标结果表明,红光可极显著地促进三角褐指藻藻细胞的Y(II)、rETRmax和α值(P<0.01),黄光处理后的三角褐指藻藻细胞的NPQ值最低,比对照组降低了63.45%(P<0.01)。RT-qPCR分析结果表明:蓝光更利于光合作用碳反应相关基因rbcL的表达;红光、蓝光、绿光和紫光可极显著地促进捕光天线合成基因fcpB的表达(P<0.01),其中红光促进fcpB基因表达的能力最强,比对照处理组提高了5.4倍。Pearson相关性分析表明:三角褐指藻岩藻黄素含量与rETRmax、fcpB基因表达呈显著正相关,与rbcL基因的表达呈极显著负相关,说明三角褐指藻可通过不同波长的光调控rETRmax参数及fcpB基因表达来提高光合作用效率,进而促进岩藻黄素的合成与积累。

In order to study the correlation between the fucoxanthin content of Phaeodactylum tricornutum and its photosynthetic physiological indexes, different monochromatic light-emitting diodes were used as light sources to treat P. tricornutum. The fucoxanthin content, photosynthetic physiological indexes, and the expressions of photosynthesis-related genes were detected, and the correlation among the indicators was examined. The results show that purple light can significantly promote fucoxanthin and chlorophyll a production of P. tricornutum (P<0.01). Under red light, the value of Y (II), maximum relative electron transfer rate (rETRmax), and alpha readings of the algae cells were significantly higher than those of the control group (P<0.01). Under yellow light, the nonphotochemical quenching value of the algae cells is at its lowest, which was 63.45% lower than that of the control group (P<0.01). The results of the quantitative reverse transcription-PCR show that blue light is more conducive to the expression of the rbcL gene. Under red, blue, green, and purple light conditions, the expression level of fcpB is significantly increased compared to the control group (P<0.01), and the expression level is increased by 5.4 times under red light. Combined with Pearson analysis, the content of fucoxanthin was positively correlated with the rETRmax and the expression of the fcpB gene, and negatively correlated with the expression of the rbcL gene. In conclusion, the synthesis and accumulation of fucoxanthin can be promoted by improving the photosynthetic efficiency of P. tricornutum, which can be done by regulating the parameters of rETRmax and the expression of the fcpB gene at different wavelengths.