Casimiro-Soriguer Inés, Narbona Eduardo, Buide M L, Del Valle José C, Whittall Justen B
Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide UniversitySeville, Spain; Department of Plant Biology and Ecology, University of SevilleSeville, Spain.
Department of Molecular Biology and Biochemical Engineering, Pablo de Olavide University Seville, Spain.
Front Plant Sci. 2016 Feb 29;7:204. doi: 10.3389/fpls.2016.00204. eCollection 2016.
Flower color polymorphisms are widely used as model traits from genetics to ecology, yet determining the biochemical and molecular basis can be challenging. Anthocyanin-based flower color variations can be caused by at least 12 structural and three regulatory genes in the anthocyanin biosynthetic pathway (ABP). We use mRNA-Seq to simultaneously sequence and estimate expression of these candidate genes in nine samples of Silene littorea representing three color morphs (dark pink, light pink and white) across three developmental stages in hopes of identifying the cause of flower color variation. We identified 29 putative paralogs for the 15 candidate genes in the ABP. We assembled complete coding sequences for 16 structural loci and nine of ten regulatory loci. Among these 29 putative paralogs, we identified 622 SNPs, yet only nine synonymous SNPs in Ans had allele frequencies that differentiated pigmented petals (dark pink and light pink) from white petals. These Ans allele frequency differences were further investigated with an expanded sequencing survey of 38 individuals, yet no SNPs consistently differentiated the color morphs. We also found one locus, F3h1, with strong differential expression between pigmented and white samples (>42x). This may be caused by decreased expression of Myb1a in white petal buds. Myb1a in S. littorea is a regulatory locus closely related to Subgroup 7 Mybs known to regulate F3h and other loci in the first half of the ABP in model species. We then compare the mRNA-Seq results with petal biochemistry which revealed cyanidin as the primary anthocyanin and five flavonoid intermediates. Concentrations of three of the flavonoid intermediates were significantly lower in white petals than in pigmented petals (rutin, quercetin and isovitexin). The biochemistry results for rutin, quercetin, luteolin and apigenin are consistent with the transcriptome results suggesting a blockage at F3h, possibly caused by downregulation of Myb1a.
花色多态性在从遗传学至生态学的广泛领域中被用作模型性状，但确定其生化和分子基础可能具有挑战性。基于花青素的花色变异可能由花青素生物合成途径（ABP）中至少12个结构基因和3个调控基因引起。我们使用mRNA测序技术对海滨蝇子草的九个样本同时进行测序并估计这些候选基因的表达，这九个样本代表了三个颜色形态（深粉色、浅粉色和白色），跨越三个发育阶段，以期确定花色变异的原因。我们在ABP中的15个候选基因中鉴定出29个推定的旁系同源基因。我们组装了16个结构基因座和10个调控基因座中的9个的完整编码序列。在这29个推定的旁系同源基因中，我们鉴定出622个单核苷酸多态性（SNP），但在花青素合酶（Ans）中只有9个同义SNP的等位基因频率能够区分有色花瓣（深粉色和浅粉色）与白色花瓣。我们通过对38个个体进行扩展测序调查进一步研究了这些Ans等位基因频率差异，但没有SNP能够始终区分颜色形态。我们还发现了一个基因座F3h1，在有色样本和白色样本之间有强烈的差异表达（>42倍）。这可能是由于白色花瓣芽中Myb1a表达降低所致。海滨蝇子草中的Myb1a是一个调控基因座，与第7亚组的Myb密切相关，已知在模式物种的ABP前半部分调控F3h和其他基因座。然后我们将mRNA测序结果与花瓣生物化学结果进行比较，结果显示矢车菊素是主要的花青素以及五种黄酮类中间体。白色花瓣中三种黄酮类中间体的浓度显著低于有色花瓣（芦丁、槲皮素和异荭草素）。芦丁、槲皮素、木犀草素和芹菜素的生物化学结果与转录组结果一致，表明在F3h处存在阻断，可能是由Myb1a的下调引起的。
Zotero 插件
