BACKGROUND Anthocyanins are common substances with many agro-food industrial applications. However, anthocyanins are generally considered to be found only in natural plants. Our previous study isolated and purified the fungus Aspergillus sydowii H-1, which can produce purple pigments during fermentation. To understand the characteristics of this strain, a transcriptomic and metabolomic comparative analysis was performed with A. sydowii H-1 from the second and eighth days of fermentation, which confer different pigment production. RESULTS We found five anthocyanins with remarkably different production in A. sydowii H-1 on the eighth day of fermentation compared to the second day of fermentation. LC-MS/MS combined with other characteristics of anthocyanins suggested that the purple pigment contained anthocyanins. A total of 28 transcripts related to the anthocyanin biosynthesis pathway was identified in A. sydowii H-1, and almost all of the identified genes displayed high correlations with the metabolome. Among them, the chalcone synthase gene (CHS) and cinnamate-4-hydroxylase gene (C4H) were only found using the de novo assembly method. Interestingly, the best hits of these two genes belonged to plant species. Finally, we also identified 530 lncRNAs in our datasets, and among them, three lncRNAs targeted the genes related to anthocyanin biosynthesis via cis-regulation, which provided clues for understanding the underlying mechanism of anthocyanin production in fungi. CONCLUSION We first reported that anthocyanin can be produced in fungus, A. sydowii H-1. Totally, 31 candidate transcripts were identified involved in anthocyanin biosynthesis, in which CHS and C4H, known as the key genes in anthocyanin biosynthesis, were only found in strain H1, which indicated that these two genes may contribute to anthocyanins producing in H-1. This discovery expanded our knowledges of the biosynthesis of anthocyanins and provided a direction for the production of anthocyanin.

中文翻译：

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鉴定真菌Sydowii H-1中新型花色苷合成途径。

背景技术花色苷是许多农业食品工业应用中的常见物质。然而，通常认为花青素仅在天然植物中发现。我们之前的研究分离并纯化了真菌Sydowii H-1，它在发酵过程中会产生紫色色素。为了了解该菌株的特性，从发酵的第二天和第八天开始，用sydowii H-1进行了转录组和代谢组学的比较分析，这赋予了不同的色素生成量。结果我们发现，与发酵第二天相比，发酵第八天在A.sydowii H-1中有五种花青素的生产有明显不同。LC-MS / MS结合花青素的其他特征表明，紫色颜料中包含花青素。在A.sydowii H-1中鉴定出总共28个与花色苷生物合成途径相关的转录本，几乎所有鉴定出的基因均与代谢组具有高度相关性。其中，查尔酮合酶基因（CHS）和肉桂酸酯-4-羟化酶基因（C4H）仅使用从头组装方法发现。有趣的是，这两个基因的最佳命中属于植物物种。最后，我们还在数据集中鉴定了530个lncRNA，其中三个lncRNA通过顺式调控靶向与花色苷生物合成相关的基因，为了解真菌中花色苷产生的潜在机制提供了线索。结论我们首先报道花青素可以在真菌A.sydowii H-1中产生。总共鉴定出31个候选花样，涉及花色苷的生物合成，其中仅在菌株H1中发现了被称为花青素生物合成关键基因的CHS和C4H，这表明这两个基因可能与在H-1中产生花青素有关。这一发现扩展了我们对花色苷生物合成的认识，并为花色苷的生产提供了方向。