Cui Hongli, Xu Wenxin, Cui Yulin, Ji Chunli, Zhang Chunhui, Qin Song, Li Runzhi
College of Agriculture, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu 030801, Shanxi, China.
Sheng Wu Gong Cheng Xue Bao. 2021 Apr 25;37(4):1260-1276. doi: 10.13345/j.cjb.200461.
The unicellular green alga Haematococcus pluvialis is the best source of natural astaxanthin (AST) in the world due to its high content under stress conditions. Although high light (HL) can effectively induce AST biosynthesis, the specific mechanisms of light signal perception and transduction are unclear. In the current study, we used transcriptomic data of normal (N), high white light (W), and high blue light (B) to study the mechanisms of light inducing AST accumulation from the point of photoreceptors. The original data of 4.0 G, 3.8 G, and 3.6 G for N, W, and B were obtained, respectively, by the Illumina Hi-seq 2000 sequencing technology. Totally, 51 954 unigenes (at least 200 bp in length) were generated, of which, 20 537 unigenes were annotated into at least one database (NR, NT, KO, SwissProt, Pfam, GO, or KOG). There were 1 255 DEGs in the W vs N, 1 494 DEGs in the B vs N, and 1 008 DEGs in the both W vs N and B vs N. KEGG enrichment analysis revealed that photosynthesis, oxidative phosphorylation, carotenoid biosynthesis, fatty acids biosynthesis, DNA replication, nitrogen metabolism, and carbon metabolism were the significantly enriched pathways. Moreover, a large number of genes encoding photoreceptors and predicted interacting proteins were predicted in Haematococcus transcriptome data. These genes showed significant differences at transcriptional expression levels. In addition, 15 related DEGs were selected and tested by qRT-PCR and the results were significantly correlated with the transcriptome data. The above results indicate that the signal transduction pathway of "light signal - photoreceptors - interaction proteins - (interaction proteins - transcription factor/transcriptional regulator) - gene expression - AST accumulation" might play important roles in the regulation process, and provide reference for further understanding the transcriptional regulation mechanisms of AST accumulation under HL stress.
单细胞绿藻雨生红球藻由于在胁迫条件下含量高，是世界上天然虾青素（AST）的最佳来源。尽管高光（HL）能有效诱导AST生物合成，但其光信号感知和转导的具体机制尚不清楚。在本研究中，我们利用正常（N）、高白光（W）和高蓝光（B）的转录组数据，从光感受器的角度研究光诱导AST积累的机制。通过Illumina Hi-seq 2000测序技术分别获得了N、W和B的原始数据4.0 G、3.8 G和3.6 G。共产生了51954个单基因（长度至少为200 bp），其中20537个单基因至少注释到一个数据库（NR、NT、KO、SwissProt、Pfam、GO或KOG）。W与N比较有1255个差异表达基因（DEG），B与N比较有1494个DEG，W与N和B与N比较均有1008个DEG。KEGG富集分析表明，光合作用、氧化磷酸化、类胡萝卜素生物合成、脂肪酸生物合成、DNA复制、氮代谢和碳代谢是显著富集的途径。此外，在雨生红球藻转录组数据中预测了大量编码光感受器和预测的相互作用蛋白的基因。这些基因在转录表达水平上表现出显著差异。此外，选择15个相关DEG进行qRT-PCR检测，结果与转录组数据显著相关。上述结果表明，“光信号-光感受器-相互作用蛋白-（相互作用蛋白-转录因子/转录调节因子）-基因表达-AST积累”的信号转导途径可能在调控过程中起重要作用，并为进一步了解HL胁迫下AST积累的转录调控机制提供参考。
