Laboratory of Molecular Biology of Tomato, Bioengineering College, Chongqing University, Chongqing, China.
Laboratory of Plant Germplasm Innovation and Utilization, School of Life Sciences, Liaocheng University, Liaocheng, China.
Plant Physiol Biochem. 2023 Dec;205:108160. doi: 10.1016/j.plaphy.2023.108160. Epub 2023 Nov 3.
Hexokinase is considered to be the key molecule in sugar signaling and metabolism. Here, we reported that silencing SlHXK1 resulted in a decrease in flower number, increased rate of flower dropping, abnormal thickening of the anther wall, and reduced pollen and seed viability. An anatomical analysis revealed the loss of small cells and abnormal thickening of anther walls in SlHXK1-RNAi lines. Treatment with auxin and 1-methylcyclopropene inhibited flower dropping from the pedicel abscission zone. qRT-PCR analysis revealed that the effect of SlHXK1 on abscission was associated with the expression levels of genes related to key meristem, auxin, ethylene, cell wall metabolism and programmed cell death. Pollen germination and pollen staining experiments showed that pollen viability was significantly reduced in the SlHXK1-RNAi lines. Physiological and biochemical analyses showed that hexokinase activity and starch content were markedly decreased in the transgenic lines. The expression of genes related to tomato pollen development was also suppressed in the transgenic lines. Although the RNAi lines eventually produced some viable seeds, the yield and quality of the seeds was lower than that of wild-type plants. Yeast two-hybrid and bimolecular fluorescence complementation assays showed that SlHXK1 interacted with SlKINγ. Furthermore, SlPIF4 inhibited the transcriptional expression of SlHXK1. In conclusion, our results demonstrate that SlHXK1 may play important roles in pollen, anther, seed and the pedicel abscission zone by affecting starch accumulation or cell wall synthesis, as well as by regulating the number of the transcripts of genes that are involved in auxin, ethylene and cell wall degradation.
己糖激酶被认为是糖信号和代谢的关键分子。在这里，我们报道了沉默 SlHXK1 导致花数减少、落花率增加、花药壁异常增厚以及花粉和种子活力降低。解剖分析显示 SlHXK1-RNAi 系中小细胞的丧失和花药壁的异常增厚。用生长素和 1-甲基环丙烯处理可抑制花梗离层区的落花。qRT-PCR 分析表明，SlHXK1 对脱落的影响与与关键分生组织、生长素、乙烯、细胞壁代谢和程序性细胞死亡相关基因的表达水平有关。花粉萌发和花粉染色实验表明，SlHXK1-RNAi 系中的花粉活力显著降低。生理生化分析表明，转基因系中己糖激酶活性和淀粉含量明显降低。与番茄花粉发育相关的基因的表达也在转基因系中受到抑制。尽管 RNAi 系最终产生了一些有活力的种子，但种子的产量和质量都低于野生型植物。酵母双杂交和双分子荧光互补实验表明 SlHXK1 与 SlKINγ 相互作用。此外，SlPIF4 抑制 SlHXK1 的转录表达。总之，我们的结果表明，SlHXK1 通过影响淀粉积累或细胞壁合成，以及通过调节参与生长素、乙烯和细胞壁降解的基因的转录本数量，在花粉、花药、种子和花梗离层区中可能发挥重要作用。
