Background

Haematococcus pluvialis is the best source of natural astaxanthin, known as the king of antioxidants. H. pluvialis have four cell forms: spore, motile cell, non-motile cell and akinete. Spores and motile cells are susceptible to photoinhibition and would die under photoinduction conditions. Photoinduction using non-motile cells as seeds could result in a higher astaxanthin production than that using akinetes. However, the mechanism of this phenomenon has not been clarified.

Results

Transcriptome was sequenced and annotated to illustrate the mechanism of this phenomenon. All differentially expressed genes involved in astaxanthin biosynthesis were up-regulated. Particularly, chyb gene was up-regulated by 16-fold, improving the conversion of β-carotene into astaxanthin. Pyruvate was the precursor of carotenoids biosynthesis. Pyruvate kinase gene expression level was increased by 2.0-fold at the early stage of akinetes formation. More changes of gene transcription occurred at the early stage of akinetes formation, 52.7% and 51.9% of total DEGs in control group and treatment group, respectively.

Conclusions

Genes transcription network was constructed and the synthesis mechanism of astaxanthin was clarified. The results are expected to further guide the in-depth optimization of the astaxanthin production process in H. pluvialis by improving pyruvate metabolism.

中文翻译：

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丙酮酸杆菌代谢影响红血球菌非运动细胞和akiakis之间虾青素的积累差异

背景

雨生红球菌是天然虾青素的最佳来源，被称为抗氧化剂之王。幽门螺杆菌有四种细胞形式：孢子，运动细胞，非运动细胞和秋葵。孢子和运动细胞易受光抑制作用，并在光诱导条件下死亡。使用非运动细胞作为种子的光诱导作用可能会比使用秋葵酶产生更高的虾青素产量。但是，这种现象的机理尚未阐明。

结果

转录组被测序和注释以说明这种现象的机理。参与虾青素生物合成的所有差异表达基因均被上调。特别地，chyb基因被上调了16倍，从而改善了β-胡萝卜素向虾青素的转化。丙酮酸是类胡萝卜素生物合成的前体。丙酮酸激酶基因表达水平在akinetes形成的早期增加了2.0倍。在骨形成的早期，基因转录的变化更多，分别为对照组和治疗组的DEGs的52.7％和51.9％。

结论

构建了基因转录网络，阐明了虾青素的合成机理。预期结果将进一步指导H中虾青素生产工艺的深入优化。雨生红球通过提高丙酮酸的代谢。