To gain a better understanding of anthocyanin biosynthesis in mulberry fruit, we analyzed the transcriptome of the mulberry varieties Da 10 (Morus atropurpurea Roxb., black fruit) and Baisang (Morus alba L., white fruit). We found that whereas Da 10 had high levels of cyanidin 3-O-glucoside (Cy), and pelargonidin 3-O-glucoside (Pg), Baisang contained only Cy, at low levels. Based on a comparative transcriptome analysis, we annotated more than 27,085 genes (including 1735 new genes). Genes that were differentially expressed between Da 10 and Baisang were detected at three stages of fruit development: S1 [4256 genes, 10 days post-anthesis (DPA)], S2 (5612 genes, 19 DPA), and S3 (5226 genes, 28 DPA). Anthocyanin biosynthesis was found to be associated with the expression of 15 core genes and 5 transcription factors. Relative to Baisang, Da 10 showed a significant upregulation of genes involved in the early stages (production of the intermediate compounds chalcone and dihydroflavonol) and late stages (production of Cy and Pg) of anthocyanin biosynthesis. Baisang showed a significant downregulation of the genes involved in the early stages of anthocyanin biosynthesis and overexpression of flavanone 3-hydroxylase (FLS), resulting in the generation of quercetin and/or myricetin but not anthocyanins. The biosynthesis of anthocyanin in mulberry fruit is initiated from the precursor, phenylalanine, and mediated by the upregulation of dihydroflavonol 4-reductase, anthocyanidin synthase, anthocyanidin 3-O-glucosyltransferase, and cyanidin-3-O-glucoside 2-O-glucuronosyltransferase, and downregulation of FLS to produce Cy and Pg.

中文翻译：

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桑树的转录组比较分析揭示了黑色（Morus atropurpurea Roxb。）和白色（Morus alba L.）水果基因型的花色苷生物合成机制。

为了更好地了解桑树果实中的花色苷生物合成，我们分析了桑树品种Da 10（桑rus，黑果）和白桑（桑al，白果）的转录组。我们发现，尽管Da 10的花青素3-O-葡萄糖苷（Cy）和pelargonidin 3-O-葡萄糖苷（Pg）含量较高，但Baisang的含量却很低。根据比较转录组分析，我们注释了超过27,085个基因（包括1735个新基因）。在果实发育的三个阶段检测到Da 10和Baisang之间差异表达的基因：S1 [4256个基因，花后10天（DPA）]，S2（5612个基因，19 DPA）和S3（5226个基因，28个DPA）。发现花青素的生物合成与15个核心基因和5个转录因子的表达有关。相对于白桑 Da 10显示了花青素生物合成的早期阶段（中间体化合物查尔酮和二氢黄酮醇的产生）和晚期阶段（Cy和Pg产生）所涉及的基因的显着上调。Baisang显示出与花青素生物合成早期有关的基因的显着下调和黄烷酮3-羟化酶（FLS）的过表达，从而导致槲皮素和/或杨梅素的生成，但未生成花青素。桑fruit中花色苷的生物合成由前体苯丙氨酸开始，并由二氢黄酮醇4-还原酶，花色苷合酶，花色苷3-O-葡糖基转移酶和花青素-3-O-葡糖苷2-O-葡糖醛酸转移酶的上调介导，并下调FLS以产生Cy和Pg。