Two distinct spontaneous mutations involved in white flower development in Lilium speciosum
Two distinct spontaneous mutations involved in white flower development in Lilium speciosum
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DOI：
10.1007/s11032-015-0389-z
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发表时间：
2015-10
影响因子：
3.1
通讯作者：
Kazuma Suzuki;Keisuke Tasaki;M. Yamagishi
中科院分区：
文献类型：
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作者：
Kazuma Suzuki;Keisuke Tasaki;M. Yamagishi
观赏百合是培育东方百合杂交种的重要野生种之一。典型L.由于花色素苷的积累，特别花具有红色的花被片和暗红色的花药。然而，白花L. speciosum具有两种不同的表型，一种为白色花被片和暗红色花药，另一种为白色花被片和黄色花药。为了阐明白色着色的分子机制，我们分离了两个调控基因和八个生物合成基因负责花青素色素沉着L。speciosumand比较了这些在红色和白色花线。在具有深红色花药的白色花被片系中，我们检测到LsMYB 12的R2重复序列中的氨基酸取代，该R2 R3-MYB调节花被片特异性花色素苷生物合成，这导致花色素苷生物合成基因转录减少并且没有花被片色素沉着。该LsMYB 12序列与白花东方百合杂交品种“Rialto”中的LhMYB 12序列相同，表明该LsMYB 12序列存在于已用于育种的品系中。另外，在具有黄色花药的白色花被片系中检测到二氢黄酮醇4-还原酶（DFR）序列的无义突变，这导致花被片和花药中缺乏花青素积累。由于白色花被片东方百合杂交品种通常具有暗红色花药，因此这种突变的DFR尚未用于百合育种。这些结果表明，百合白色花的产生有多种机制，为培育具有新花色组合的东方百合品种奠定了基础。
Lilium speciosumis one of the most important wild species used for breeding Oriental hybrid lily cultivars. TypicalL. speciosumflowers possess red tepals and dark red anthers because of anthocyanin accumulation. However, white-floweredL. speciosumwith two distinct phenotypes, one with white tepals and dark red anthers and the other with white tepals and yellow anthers, also exists. To elucidate the molecular mechanisms underlying white colouration, we isolated two regulatory genes and eight biosynthetic genes responsible for anthocyanin pigmentation inL. speciosumand compared these in red- and white-flowered lines. In the white tepal line with dark red anthers, we detected an amino acid substitution in the R2 repeat of LsMYB12, the R2R3-MYB that regulates tepal-specific anthocyanin biosynthesis, which led to reduced anthocyanin biosynthetic gene transcription and no tepal pigmentation. ThisLsMYB12sequence was identical to that of anLhMYB12in the white-flowered Oriental hybrid lily cultivar ‘Rialto’, indicating that thisLsMYB12sequence is present in lines that have been used for breeding. In addition, a nonsense mutation was detected in thedihydroflavonol 4-reductase(DFR) sequence of the white tepal line with yellow anthers, which resulted in a lack of anthocyanin accumulation in tepals and anthers. This mutatedDFRhas not been used for lily breeding because white tepal Oriental hybrid lily cultivars usually have dark red anthers. These results suggest that several mechanisms generate white flowers in lilies, and provide a substantial foundation for the production of Oriental hybrid lily cultivars with novel flower colour combinations.