Han Mei, Xu Xianglei, Xiong Yuan, Wei Haikun, Yao Kejun, Huang Tingting, Long Yingle, Su Tao
Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China.
Key Laboratory of State Forestry Administration on Subtropical Forest Biodiversity Conservation, Nanjing Forestry University, Nanjing 210037, China.
Plants (Basel). 2022 Aug 3;11(15):2025. doi: 10.3390/plants11152025.
Hexokinase (HXK) family proteins exert critical roles in catalyzing hexose phosphorylation, sugar sensing, and modulation of plant growth and stress adaptation. Nevertheless, a large amount remains unknown about the molecular profile of HXK enzymes in , a woody model tree species. A genome-wide survey of HXK-encoding genes, including phylogenies, genomic structures, exon/intron organization, chromosomal distribution, and conserved features, was conducted, identifying six putative HXK isogenes () in the genome. The evolutionary tree demonstrated that 135 homologous HXKs between 17 plant species were categorized into four major subfamilies (type A, B, C, and D), clustering one plastidic () and five mitochondrial grouped into type A and B, respectively. The in silico deduction prompted the presence of the conserved sugar-binding core (motif 4), phosphorylation sites (motif 2 and 3), and adenosine-binding domains (motif 7). The transcriptomic sequencing (RNA-seq) and the quantitative real-time PCR (qRT-PCR) assays revealed that three isogenes (, and ) were abundantly expressed in leaves, stems, and roots, while others appeared to be dominantly expressed in the reproductive tissues. Under the stress exposure, and displayed a significant induction upon the pathogenic fungi () infection and marked promotions by glucose feeding in roots. In contrast, the and are ABA-responsive genes, following a dose-dependent manner. The comprehensive analyses of the genomic patterns and expression profiling provide theoretical clues and lay a foundation for unraveling the physiological and signaling roles underlying the fine-tuned PtHXKs responding to diverse stressors.
己糖激酶（HXK）家族蛋白在催化己糖磷酸化、糖感知以及调节植物生长和胁迫适应方面发挥着关键作用。然而，关于木本模式树种毛果杨中HXK酶的分子特征，仍有大量未知之处。我们对编码HXK的基因进行了全基因组调查，包括系统发育、基因组结构、外显子/内含子组织、染色体分布和保守特征，在毛果杨基因组中鉴定出6个假定的HXK同源基因（PtHXKs）。进化树表明，17种植物中的135个同源HXK被分为四个主要亚家族（A、B、C和D型），其中一个质体HXK和五个线粒体HXK分别聚类为A和B型。电子推导表明存在保守的糖结合核心（基序4）、磷酸化位点（基序2和3）和腺苷结合结构域（基序7）。转录组测序（RNA-seq）和定量实时PCR（qRT-PCR）分析表明，三个同源基因（PtHXK1、PtHXK2和PtHXK3）在叶、茎和根中大量表达，而其他基因似乎在生殖组织中占主导地位。在胁迫处理下，PtHXK1和PtHXK2在致病真菌感染后表现出显著诱导，在根部通过葡萄糖饲喂显著促进表达。相反，PtHXK4和PtHXK5是ABA响应基因，呈剂量依赖性。对基因组模式和表达谱进行的综合分析提供了理论线索，为揭示PtHXKs在微调以响应各种应激源时的生理和信号传导作用奠定了基础。
