School of Life Sciences, Shanxi University, Taiyuan, 030006, Shanxi, China.
Department of Plant and Soil Sciences, Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, KY, 40546, USA.
Planta. 2018 Jul;248(1):171-182. doi: 10.1007/s00425-018-2888-8. Epub 2018 Apr 11.
Genome-wide identification, expression analysis, and functional characterization of previously uncharacterized hexokinase family of oil crop, Brassica napus, underscore the importance of this gene family in plant growth and development. In plants, the multi-gene family of dual-function hexokinases (HXKs) plays important roles in sugar metabolism and sensing that affect growth and development. Rapeseed (Brassica napus L.) is an important oil crop; however, little is known about the B. napus HXK gene family. We identified 19 putative HXKs in B. napus genome. B. rapa and B. oleracea, the two diploid progenitors of B. napus, contributed almost equally to the BnHXK genes. Phylogenetic analysis divided the 19 BnHXKs into four groups. The exon-intron structures of BnHXKs share high similarity to those of HXKs in Arabidopsis and rice. The group III and IV BnHXKs are highly expressed in roots, whereas group I members preferentially express in leaves. Analysis of seed transcriptomes at different developmental stages showed that most of group I and IV HXKs are highly expressed 2-weeks after pollination (2WAP), compared to 4WAP for group III. BnHKXs are differentially expressed in susceptible and tolerant B. napus cultivars after fungal infection, suggesting the possible involvement in defense response. We generated rapeseed RNAi lines for BnHXK9, a member of relatively less characterized group IV, by pollen-mediated gene transformation. The seedlings of BnHXK9-RNAi lines showed delayed growth compared to the wild type. The RNAi plants were dwarf with curly leaves, suggesting the involvement of BnHXK9 in plant development. Collectively, our findings provides a comprehensive account of BnHXK gene family in an important crop and a starting point for further elucidation of their roles in sugar metabolism and sensing, as well as plant growth and development.
在植物中，多功能双功能己糖激酶（HXK）的多基因家族在影响生长和发育的糖代谢和感应中发挥重要作用。油菜（Brassica napus L.）是一种重要的油料作物；然而，人们对油菜 HXK 基因家族知之甚少。我们在油菜基因组中鉴定了 19 个推定的 HXK。油菜的两个二倍体祖先白菜和甘蓝，几乎对等贡献了 BnHXK 基因。系统发育分析将 19 个 BnHXKs 分为 4 组。BnHXKs 的外显子-内含子结构与拟南芥和水稻的 HXKs 高度相似。第 III 组和第 IV 组 BnHXKs 在根中高度表达，而第 I 组成员则优先在叶片中表达。不同发育阶段种子转录组分析表明，与第 III 组相比，大多数第 I 组和第 IV 组 HXK 在授粉后 2 周（2WAP）高度表达。BnHKXs 在真菌感染后在易感和耐油菜品种中差异表达，表明它们可能参与防御反应。我们通过花粉介导的基因转化生成了油菜 RNAi 系，用于相对较少表征的第 IV 组的 BnHXK9。与野生型相比，BnHXK9-RNAi 系的幼苗生长缓慢。RNAi 植物矮小，叶片卷曲，表明 BnHXK9 参与植物发育。总的来说，我们的研究结果为重要作物的 BnHXK 基因家族提供了全面的描述，并为进一步阐明它们在糖代谢和感应以及植物生长和发育中的作用提供了起点。
