Although anthocyanin color patterns on flowers are among the most attractive characteristics, the genetic mechanisms through which color patterns are developed are not well understood, especially for color patterns associated with altered petal structure. Lilium species and cultivars often develop raised spots, where the interior surfaces of tepals increase to develop bumps with accompanying anthocyanin accumulation. The aim of this study was to identify transcription factors regulating pigmentation of the bumps. We identified two R2R3-MYB genes, MYB19Long and MYB19Short, in Lilium leichtlinii, L. lancifolium, and Asiatic hybrid lily cultivars. Their amino acid sequences were similar; however, part of the C-terminal region was triplicated in MYB19Long. Spatial and temporal expression profiles in lilies were strongly associated with anthocyanin biosynthesis gene expression in the bumps, and some defects were found in these genes in L. lancifolium 'Pure Gold' that developed colorless bumps. Thus, both MYB19Long and MYB19Short were likely to be involved in the bump pigmentation. MYB19Long had a stronger ability to stimulate target gene expression than MYB19Short, and expression levels of MYB19Long were greater than those of MYB19Short in lily tepals; thus, the ability to biosynthesize anthocyanin pigments was greater for MYB19Long than for MYB19Short. Among the F1 population, MYB19Short expression was found only in the tepals of F1 plants that developed bumps, although all of the F1 plants possessed the MYB19Short gene, indicating that MYB19 expression followed bump development. These findings helped to elucidate the genetic mechanisms underlying raised spot development.

中文翻译：

---

百合 (Lilium spp.) 斑点花青素色素沉着相关 MYB 转录因子 (MYB19Long 和 MYB19Short) 的分离鉴定

尽管花朵上的花青素颜色图案是最吸引人的特征之一，但颜色图案形成的遗传机制尚不清楚，尤其是与花瓣结构改变相关的颜色图案。百合物种和栽培品种通常会出现凸起的斑点，在这些地方，花被片的内表面增加形成凸起，伴随着花青素的积累。本研究的目的是确定调节肿块色素沉着的转录因子。我们在 Lilium leichtlinii、L. lancifolium 和亚洲杂交百合品种中鉴定了两个 R2R3-MYB 基因，MYB19Long 和 MYB19Short。它们的氨基酸序列相似；然而，部分 C 端区域在 MYB19Long 中重复三次。百合的时空表达谱与凸起中的花青素生物合成基因表达密切相关，并且在长出无色凸起的 L. lancifolium 'Pure Gold' 中的这些基因中发现了一些缺陷。因此，MYB19Long 和 MYB19Short 都可能与肿块色素沉着有关。MYB19Long对靶基因表达的刺激能力强于MYB19Short，在百合花被片中MYB19Long的表达水平高于MYB19Short；因此，MYB19Long 比 MYB19Short 生物合成花青素色素的能力更强。在 F1 群体中，MYB19Short 表达仅在发育凸块的 F1 植物的花被中发现，尽管所有 F1 植物都具有 MYB19Short 基因，表明 MYB19 表达跟随凸块发育。