Plant Genomics and Molecular Improvement of Colored Fiber Laboratory, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, People's Republic of China.
College of Textile Science and Engineering, Zhejiang Sci-Tech University, Hangzhou, 310018, People's Republic of China.
Mol Biol Rep. 2023 Jun;50(6):4865-4873. doi: 10.1007/s11033-023-08420-6. Epub 2023 Apr 13.
The naturally colored brown cotton fiber is the most widely used environmentally friendly textile material, which primarily contains proanthocyanidins and their derivatives. Many structural genes in the flavonoid synthesis pathway are known to improve the genetic resources of naturally colored cotton. Among them, DFR is a crucial late enzyme to synthesis both anthocyanins and proanthocyanidins in the plant flavonoid pathway.
The protein sequences of GhDFRs were analyzed using bioinformatic tools. The expression levels of GhDFRs in various tissues and organs of upland cotton Zongxu1 (ZX1), were analyzed by quantitative real-time PCR, and the expression pattern of GhDFR1 during fiber development of white cotton and brown cotton was analyzed further. The function of GhDFR1 in NCC ZX1 was preliminarily analyzed by virus induced gene silencing (VIGS) technology.
Bioinformatic analysis revealed that GhDFRs sequences in upland cotton genome were extremely conserved. Furthermore, evolutionary tree analysis revealed that the functions of GhDFR1 and GhDFR2, and GhDFR3 and GhDFR4, presented different and shared some similarities. Our study showed GhDFR1 and GhDFR2 were specifically expressed in fibers, while GhDFR3 and GhDFR4 were specifically expressed in petals. GhDFR1 was exclusively expressed in brown cotton fiber at various stages of development and progressively increased with the growth of fiber, but the trend of expression in white cotton was quite the opposite. We silenced GhDFR1 expression in brown cotton fiber using VIGS technology, and observed the VIGS-interference plants. After reducing the expression level of GhDFR1, the period for significant GhDFR1 expression in the developing fibers changed, reducing the content of anthocyanins, and lightening the color of mature cotton fibers.
GhDFR1 was preferentially expressed in brown cotton during fiber development. The timing of GhDFR1 expression for flavonoid synthesis altered, resulting in anthocyanin contents reduced and the fiber color of the GhDFR1i lines lightened. These findings showed the role of GhDFR1 in fiber coloration of NCC and provided a new candidate for NCC genetic improvement.
天然彩色棕色棉纤维是应用最广泛的环保纺织材料，主要含有原花青素及其衍生物。许多类黄酮合成途径中的结构基因被认为可以改善天然彩色棉的遗传资源。其中，DFR 是植物类黄酮途径中合成花青素和原花青素的关键晚期酶。
使用生物信息学工具分析 GhDFRs 的蛋白质序列。通过定量实时 PCR 分析陆地棉宗绪 1 号（ZX1）不同组织和器官中 GhDFRs 的表达水平，进一步分析白色棉花和棕色棉花纤维发育过程中 GhDFR1 的表达模式。利用病毒诱导基因沉默（VIGS）技术初步分析 GhDFR1 在 NCC ZX1 中的功能。
生物信息学分析表明，陆地棉基因组中 GhDFRs 序列高度保守。此外，进化树分析表明，GhDFR1 和 GhDFR2 的功能以及 GhDFR3 和 GhDFR4 的功能呈现不同但又有一些相似之处。我们的研究表明，GhDFR1 和 GhDFR2 特异性表达在纤维中，而 GhDFR3 和 GhDFR4 特异性表达在花瓣中。GhDFR1 仅在棕色棉纤维的各个发育阶段表达，并随纤维的生长而逐渐增加，但在白色棉中的表达趋势则完全相反。我们利用 VIGS 技术沉默了棕色棉纤维中的 GhDFR1 表达，并观察到 VIGS 干扰植株。降低 GhDFR1 的表达水平后，发育纤维中 GhDFR1 显著表达的时期发生改变，导致花色苷含量降低，成熟棉纤维颜色变浅。
GhDFR1 在纤维发育过程中优先在棕色棉中表达。类黄酮合成中 GhDFR1 表达的时间改变，导致花色苷含量降低，GhDFR1i 系纤维颜色变浅。这些发现表明 GhDFR1 在 NCC 纤维颜色形成中的作用，并为 NCC 遗传改良提供了新的候选基因。
