National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India.
J Exp Bot. 2023 Jan 1;74(1):130-148. doi: 10.1093/jxb/erac392.
Flower and seed coat colour are important agronomic traits in chickpea (Cicer arietinum L.). Cultivated chickpeas are of two types namely, desi (dark seeded, purple flowered) and kabuli (light seeded, white flowered). There has been limited information about the molecular mechanism underlying colour variation of flower and seed coats in desi and kabuli chickpea. We profiled the anthocyanin and proanthocyanidin (PA) contents in chickpea flowers and seed coats. Tissue-specific silencing of two genes encoding a basic helix-loop-helix (CabHLH) protein and a tonoplast-localized multidrug and toxic compound extrusion (CaMATE1) transporter in a desi genotype resulted in the reduction in expression of anthocyanin and PA biosynthetic genes and anthocyanin and PA contents in the flower and seed coat, and produced flowers and seeds with kabuli characteristics. Transcriptional regulation of a subset of anthocyanin and PA biosynthetic genes by a natural CabHLH variant and transport assay of a natural CaMATE1 variant explained the association of these alleles with the kabuli phenotype. We carried out a detailed molecular characterization of these genes, and provided evidence that kabuli chickpea flower and seed colour phenotypes can be derived by manipulation of single genes in a desi chickpea background.
花和种皮颜色是鹰嘴豆（Cicer arietinum L.）重要的农艺性状。栽培的鹰嘴豆有两种类型，即：desi（深色种子，紫色花）和 kabuli（浅色种子，白色花）。关于 desi 和 kabuli 鹰嘴豆花和种皮颜色变化的分子机制，信息有限。我们对鹰嘴豆花和种皮中的花色苷和原花色苷（PA）含量进行了分析。在 desi 基因型中，通过组织特异性沉默两个基因（编码一个碱性螺旋-环-螺旋（CabHLH）蛋白和一个液泡定位的多药和毒性化合物外排（CaMATE1）转运蛋白），导致花色苷和 PA 生物合成基因的表达减少，花和种皮中的花色苷和 PA 含量降低，产生具有 kabuli 特征的花和种子。天然 CabHLH 变体对一组花色苷和 PA 生物合成基因的转录调控以及天然 CaMATE1 变体的转运测定解释了这些等位基因与 kabuli 表型的关联。我们对这些基因进行了详细的分子特征分析，提供了证据表明，通过在 desi 鹰嘴豆背景下操纵单个基因，可以获得 kabuli 鹰嘴豆花和种皮颜色表型。
