Citrus Research and Education Center, IFAS, University of Florida, Lake Alfred, FL 33850, USA.
Citrus Research and Education Center, IFAS, University of Florida, Lake Alfred, FL 33850, USA; Pomology Department, Faculty of Agriculture, Mansoura University, Mansoura 35516, Egypt.
Plant Sci. 2022 Oct;323:111401. doi: 10.1016/j.plantsci.2022.111401. Epub 2022 Jul 26.
Citrus is a major fruit crop cultivated on a global scale. Citrus trees are long lived perennials with a large canopy. Understanding the genetic control of tree architecture could provide tools for breeding and selection of citrus cultivars suitable for high density planting with improved light exposure. Tree architecture is modulated by the TILLER ANGLE CONTROL 1 (TAC1) gene which plays an important role in the regulation of the shoot angle. Herein, we used CRISPR/Cas9 technology to knockout the CsTAC1 gene for the biochemical and molecular analysis of its function. Nine transgenic lines were obtained, and five edited plants were confirmed based on T7EI mismatch detection assay and Sanger sequencing. The transgenic citrus lines exhibited pleiotropic phenotypes, including differences in branch angle and stem growth. Additionally, silencing CsTAC1 led to enhanced CsLAZY1 transcript levels in the tested lines. Analysis of the phytohormonal profile revealed that TAC1-edited plants exhibited lower auxin contents and increased cytokinin levels in the leaves compared to the wild-type plants. The GA gibberellin level was enhanced in most of the edited lines. Collectively, TAC1 affects branch angle in association with hormone signals in citrus.
柑橘是一种在全球范围内广泛种植的主要水果作物。柑橘树是多年生常绿乔木，树冠较大。了解树木结构的遗传控制，可以为培育和选择适合高密度种植、改善光照条件的柑橘品种提供工具。树木结构由 TILLER ANGLE CONTROL 1（TAC1）基因调控，该基因在调节枝条角度方面起着重要作用。在此，我们利用 CRISPR/Cas9 技术敲除 CsTAC1 基因，以进行其功能的生化和分子分析。获得了 9 个转基因株系，并通过 T7EI 错配检测和 Sanger 测序确认了 5 个编辑植株。转基因柑橘株系表现出多种表型，包括分枝角度和茎生长的差异。此外，沉默 CsTAC1 导致测试株系中 CsLAZY1 转录本水平升高。激素分析表明，与野生型植株相比，TAC1 编辑植株叶片中的生长素含量较低，细胞分裂素水平较高，赤霉素 GA 水平在大多数编辑株系中升高。总之，TAC1 通过与激素信号相互作用影响柑橘的分枝角度。
