The A locus that controls anthocyanin accumulation in pepper encodes a MYB transcription factor homologous to Anthocyanin2 of Petunia
The A locus that controls anthocyanin accumulation in pepper encodes a MYB transcription factor homologous to Anthocyanin2 of Petunia
复制标题
DOI：
10.1007/s00122-004-1625-9
复制
发表时间：
2004-06-01
影响因子：
5.4
通讯作者：
Paran, I
中科院分区：
文献类型：
--
作者：
Borovsky, Y;Oren-Shamir, M;Paran, I
含有显性A基因的辣椒植物在叶子、花和未成熟的果实中积累花青素色素。我们之前将 5226（紫色果实）和 PI 159234（绿色果实）杂交的 F-2 后代中辣椒染色体 10 上的 A 映射到与番茄中矮牵牛花青素 2 (An2)（花青素生物合成调节剂）位置相对应的区域。这表明 A 编码 Petunia An2 的同源物。使用An2的序列和相应的番茄表达序列标签，我们分离了与An2同源的辣椒cDNA，其与A共分离。随后，我们使用从5226和PI 159234的果实、花和叶中提取的RNA，通过Northern分析确定了A的表达。在5226中，在果实发育的所有阶段以及花和叶中均检测到表达。相比之下，A在PI 159234的采样组织中不表达。绿果基因型和紫果基因型之间A的基因组序列比较显示编码区没有差异，表明绿色基因型中A缺乏表达可归因于启动子区域的变异。通过分析5226和PI 159234花青素生物合成途径中结构基因的表达，发现与Petunia类似，该途径中的早期基因独立于A调控，而晚期基因的表达依赖于A。
Pepper plants containing the dominant A gene accumulate anthocyanin pigments in the foliage, flower and immature fruit. We previously mapped A to pepper chromosome 10 in the F-2 progeny of a cross between 5226 (purple-fruited) and PI 159234 (green-fruited) to a region that corresponds, in tomato, to the location of Petunia anthocyanin 2 (An2), a regulator of anthocyanin biosynthesis. This suggested that A encodes a homologue of Petunia An2. Using the sequences of An2 and a corresponding tomato expressed sequence tag, we isolated a pepper cDNA orthologous to An2 that cosegregated with A. We subsequently determined the expression of A by Northern analysis, using RNA extracted from fruits, flowers and leaves of 5226 and PI 159234. In 5226, expression was detected in all stages of fruit development and in both flower and leaf. In contrast, A was not expressed in the sampled tissues in PI 159234. Genomic sequence comparison of A between green- and purple-fruited genotypes revealed no differences in the coding region, indicating that the lack of expression of A in the green genotypes can be attributed to variation in the promoter region. By analyzing the expression of the structural genes in the anthocyanin biosynthetic pathway in 5226 and PI 159234, it was determined that, similar to Petunia, the early genes in the pathway are regulated independently of A, while expression of the late genes is A-dependent.