Key Laboratory of Vegetable Germplasm Innovation and Utilization of Hebei, Collaborative Innovation Center of Vegetable Industry in Hebei, College of Horticulture, Hebei Agricultural University, Baoding, China.
College of Life Sciences, Hebei Agricultural University, Baoding, China.
Plant J. 2022 Aug;111(4):1096-1109. doi: 10.1111/tpj.15877. Epub 2022 Jul 18.
Anthocyanins are important pigments that impart color in plants. In Solanum, different species display various fruit or flower colors due to varying degrees of anthocyanin accumulation. Here we identified two anthocyanin-free mutants from an ethylmethane sulfonate-induced mutant library and naturally occurring mutants in Solanum melongena, with mutations in the 5' splicing site of the second intron of dihydroflavonol-4-reductase (DFR) - leading to altered splicing. Further study revealed that alternative splicing of the second intron was closely related to anthocyanin accumulation in 17 accessions from three cultivated species: S. melongena, Solanum macrocarpon and Solanum aethiopicum, and their wild related species. Analysis of natural variations of DFR, using an expanded population including 282 accessions belonging to the spiny Solanum group, identified a single-nucleotide polymorphism in the MYB recognition site in the promoter region, which causes differential expression of DFR and affects anthocyanin accumulation in fruits of the detected accessions. Our study suggests that, owing to years of domestication, the natural variation in the DFR promoter region and the alternative splicing of the DFR gene account for altered anthocyanin accumulation during spiny Solanum domestication.
花色苷是赋予植物颜色的重要色素。在茄属植物中，由于花色苷积累程度的不同，不同物种表现出不同的果实或花的颜色。在这里，我们从乙磺酸乙酯诱导的突变体文库和自然发生的茄子突变体中鉴定出两个花色苷缺失突变体，其突变位于二氢黄酮醇 4-还原酶（DFR）第二内含子 5'剪接位点，导致剪接改变。进一步的研究表明，第二内含子的选择性剪接与三个栽培种（茄子、大果番茄和茄）及其野生近缘种 17 个材料中的花色苷积累密切相关。利用包括 282 个属于多刺茄组的材料的扩展群体，对 DFR 的自然变异进行分析，在启动子区域的 MYB 识别位点发现了一个单核苷酸多态性，这导致 DFR 的差异表达，并影响了检测到的材料果实中的花色苷积累。我们的研究表明，由于多年的驯化，DFR 启动子区域的自然变异和 DFR 基因的选择性剪接导致了多刺茄驯化过程中花色苷积累的改变。
