Li Na-Na, Qian Wen-Jun, Wang Lu, Cao Hong-Li, Hao Xin-Yuan, Yang Ya-Jun, Wang Xin-Chao
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China; Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture, Hangzhou 310008, China.
National Center for Tea Plant Improvement, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310008, China; College of Horticulture, Northwest Agriculture and Forestry University, Yangling 712100, China.
J Plant Physiol. 2017 Feb;209:95-104. doi: 10.1016/j.jplph.2016.11.007. Epub 2016 Nov 25.
Hexokinases (HXKs, EC 2.7.1.1) and fructokinases (FRKs, EC 2.7.1.4) play important roles in carbohydrate metabolism and sugar signaling during the growth and development of plants. However, the HXKs and FRKs in the tea plant (Camellia sinensis) remain largely unknown. In this manuscript, we present the molecular characterization, phylogenetic relationships, conserved domains and expression profiles of four HXK and seven FRK genes of the tea plant. The 11 deduced CsHXK and CsFRK proteins were grouped into six main classes. All of the deduced proteins, except for CsFKR7, possessed putative ATP-binding motifs and a sugar recognition region. These genes exhibited tissue-specific expression patterns, which suggests that they play different roles in the metabolism and development of source and sink tissues in the tea plant. There were variations in CsHXKs and CsFRKs transcript abundance in response to four abiotic stresses: cold, salt, drought and exogenous abscisic acid (ABA). Remarkably, CsHXK3 and CsHXK4 were significantly induced in the leaves and roots under cold conditions, CsHXK1 was apparently up-regulated in the leaves and roots under salt and drought stresses, and CsHXK3 was obviously stimulated in the leaves and roots under short-term treatment with exogenous ABA. These findings demonstrate that CsHXKs play critical roles in response to abiotic stresses in the tea plant. Our research provides a fundamental understanding of the CsHXK and CsFRK genes of the tea plant and important information for the breeding of stress-tolerant tea cultivars.
己糖激酶（HXKs，EC 2.7.1.1）和果糖激酶（FRKs，EC 2.7.1.4）在植物生长发育过程中的碳水化合物代谢和糖信号传导中发挥着重要作用。然而，茶树（Camellia sinensis）中的HXKs和FRKs在很大程度上仍不为人所知。在本论文中，我们展示了茶树中四个HXK基因和七个FRK基因的分子特征、系统发育关系、保守结构域和表达谱。推导得到的11个CsHXK和CsFRK蛋白被分为六个主要类别。除CsFKR7外，所有推导得到的蛋白都具有假定的ATP结合基序和一个糖识别区域。这些基因呈现出组织特异性的表达模式，这表明它们在茶树源库组织的代谢和发育中发挥着不同的作用。CsHXKs和CsFRKs的转录本丰度在响应四种非生物胁迫时存在差异：寒冷、盐胁迫、干旱和外源脱落酸（ABA）。值得注意的是，CsHXK3和CsHXK4在寒冷条件下的叶片和根中显著诱导表达，CsHXK1在盐胁迫和干旱胁迫下的叶片和根中明显上调，CsHXK3在短期外源ABA处理下的叶片和根中明显受到刺激。这些发现表明CsHXKs在茶树对非生物胁迫的响应中起关键作用。我们的研究为茶树CsHXK和CsFRK基因提供了基本认识，并为培育耐胁迫茶树品种提供了重要信息。
