Evolutionary blocks to anthocyanin accumulation and the loss of an anthocyanin carrier protein in betalain-pigmented Caryophyllales
Evolutionary blocks to anthocyanin accumulation and the loss of an anthocyanin carrier protein in betalain-pigmented Caryophyllales
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DOI：
10.1101/2022.10.19.512958
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发表时间：
2022-10
期刊：
影响因子：
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通讯作者：
Boas Pucker;Nathanael Walker-Hale;Won Yim;John Cushman;A. Crum;Ya Yang;Samuel F. Brockington
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文献类型：
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作者：
Boas Pucker;Nathanael Walker-Hale;Won Yim;John Cushman;A. Crum;Ya Yang;Samuel F. Brockington
红铃兰目具有复杂的色素进化，花青素和甜菜色素相互排斥。鉴于最近有证据表明甜菜色素色素沉着的多重转变，我们重新评估了从甜菜色素谱系中排除花青素的潜在机制。我们使用转录组学和基因组数据集研究了类黄酮途径的进化，涵盖了31个家族的309个物种。已知的类黄酮合成基因的直系同源物和旁系同源物通过序列相似性鉴定，通过系统发育和同线分析推断基因重复和基因丢失。相对转录丰度进行了评估，以揭示广泛的基因表达之间的变化甜菜色素和花青素色素的谱系。大多数类黄酮基因在甜菜色素谱系中保留和转录，并且许多还显示出甜菜色素谱系内广泛的基因重复的证据。然而，几个类黄酮基因的表达在甜菜色素色素谱系中减少，特别是后期基因二氢黄酮醇4-还原酶（DFR）和花青素合成酶（ANS）。值得注意的是，类黄酮3′，5 ′-羟化酶（F3′5′H）同源物在甜菜色素着色的谱系中反复丢失，并且花青素9（AN 9）同源物在任何甜菜色素着色的谱系中都检测不到。ANS和DFR同源物表达的下调（限制合成）和AN 9同源物的逐渐丧失（限制运输），与向甜菜色素着色的多次转变一致，可能是甜菜色素着色的红花属中花青素丧失的关键。
◻ The order Caryophyllales exhibits complex pigment evolution, with mutual exclusion of anthocyanin and betalain pigments. Given recent evidence for multiple shifts to betalain pigmentation, we re-evaluated potential mechanisms underpinning the exclusion of anthocyanins from betalain-pigmented lineages. ◻ We examined the evolution of the flavonoid pathway using transcriptomic and genomic datasets covering 309 species in 31 families. Orthologs and paralogs of known flavonoid synthesis genes were identified by sequence similarity, with gene duplication and gene loss inferred by phylogenetic and syntenic analysis. Relative transcript abundances were assessed to reveal broad-scale gene expression changes between betalain- and anthocyanin-pigmented lineages. ◻ Most flavonoid genes are retained and transcribed in betalain-pigmented lineages, and many also show evidence of extensive gene duplication within betalain-pigmented lineages. However, expression of several flavonoid genes is reduced in betalain-pigmented lineages, especially the late-stage genes dihydroflavonol 4-reductase (DFR) and anthocyanidin synthase (ANS). Notably flavonoid 3′,5′-hydroxylase (F3′5′H) homologs have been repeatedly lost in belatain-pigmented lineages, and Anthocyanin9 (AN9) homologs are undetectable in any betalain-pigmented lineages. ◻ Down-regulation of ANS and DFR homolog expression (limiting synthesis) and reiterative loss of AN9 homologs (limiting transport), coincident with multiple shifts to betalain pigmentation, are likely crucial the loss of anthocyanins in betalain-pigmented Caryophyllales.