Feng Xiaojie, Li Shuzhen, Meng Di, Di Qinghua, Zhou Mengdi, Yu Xianchang, He Chaoxing, Yan Yan, Wang Jun, Sun Mintao, Li Yansu
State Key Laboratory of Vegetable Biobreeding, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China.
Ganzhou Key Laboratory of Greenhouse Vegetable, College of Life Science, Gannan Normal University, Ganzhou, China.
Physiol Plant. 2023 Jul-Aug;175(4):e13977. doi: 10.1111/ppl.13977.
BASIC PENTACYSTEINE (BPCs) transcription factors are important regulators of plant growth and development. However, the regulatory mechanism of BPC2 in roots remains unclear. In our previous study, we created Csbpc2 cucumber mutants by the CRISPR/Cas9 system, and our studies on the phenotype of Csbpc2 mutants showed that the root growth was inhibited compared with wide-type (WT). Moreover, the surface area, volume and number of roots decreased significantly, with root system architecture changing from dichotomous branching to herringbone branching. Compared with WT, the leaf growth of the Csbpc2 mutants was not affected. However, the palisade and spongy tissue were significantly thinner, which was not beneficial for photosynthesis. The metabolome of root exudates showed that compared with WT, amino acids and their derivatives were significantly decreased, and the enriched pathways were mainly regulated by amino acids and their derivatives, indicating that knockout of CsBPC2 mainly affected the amino acid content in root exudates. Importantly, transcriptome analysis showed that knockout of CsBPC2 mainly affected root gene expression. Knockout of CsBPC2 significantly reduced the gene expression of gibberellins synthesis. However, the expression of genes related to amino acid synthesis, nitrogen fixation and PSII-related photosynthesis increased significantly, which may be due to the effect of knocking out CsBPC2 on gibberellins synthesis, resulting in the inhibition of seedling growth, thus forming negative feedback regulation. Generally, we showed for the first time that BPC2 is a key regulator gene of root growth and development, laying the foundation for future mechanisms of BPC2 regulation in roots.
基础五胱氨酸（BPCs）转录因子是植物生长发育的重要调节因子。然而，BPC2在根中的调控机制仍不清楚。在我们之前的研究中，我们通过CRISPR/Cas9系统创建了Csbpc2黄瓜突变体，对Csbpc2突变体表型的研究表明，与野生型（WT）相比，其根生长受到抑制。此外，根的表面积、体积和数量显著减少，根系结构从二叉分枝变为鱼骨状分枝。与WT相比，Csbpc2突变体的叶片生长未受影响。然而，栅栏组织和海绵组织明显变薄，这不利于光合作用。根分泌物的代谢组学表明，与WT相比，氨基酸及其衍生物显著减少，富集的途径主要受氨基酸及其衍生物调控，表明CsBPC2的敲除主要影响根分泌物中的氨基酸含量。重要的是，转录组分析表明，CsBPC2的敲除主要影响根基因表达。CsBPC2的敲除显著降低了赤霉素合成的基因表达。然而，与氨基酸合成、固氮和PSII相关光合作用相关的基因表达显著增加，这可能是由于敲除CsBPC2对赤霉素合成的影响，导致幼苗生长受到抑制，从而形成负反馈调节。总体而言，我们首次表明BPC2是根生长发育的关键调节基因，为未来研究BPC2在根中的调控机制奠定了基础。
