薛鑫 周心智 决登伟

摘  要：WRKY转录因子在植物的生长发育和逆境胁迫响应中起着重要作用。前期研究发现，部分WRKY基因（比如DlWRKY52）参与了龙眼的成花诱导和逆境胁迫响应过程。为进一步研究龙眼WRKY基因的功能，以‘四季蜜龙眼叶片cDNA为模板克隆得到DlWRKY52基因，并对其序列特征、组织表达模式、花果发育过程表达模式及亚细胞定位进行研究。结果表明：DlWRKY52基因的开放阅读框（open reading frame， ORF）全长为918 bp，编码306个氨基酸，具有典型的WRKY结构域和锌指结构，属于Ⅱc型WRKY蛋白。qRT-PCR结果表明，DlWRKY52基因在叶片、茎和果实器官中高表达;在花后80 d的果肉中显著上调表达;特异在‘四季蜜成花诱导中下调表达。拟南芥原生质体瞬时表达结果显示，荧光信号主要集中在细胞核。上述结果表明，作为典型的转录因子，DlWRKY52编码的蛋白定位于细胞核。DlWRKY52可能参与了龙眼成花诱导及果实早期发育调控。

关键词：龙眼;WRKY;转录因子;表达分析;蛋白亚细胞定位

中图分类号：S188      文献标识码：A

Abstract： WRKY transcription factors plays an important role in plant growth， development and stress response. Based on a previous study， we found several WRKY genes， such as DlWRKY52， were participated in the process of floral induction and stress response. To further reveal the function of longan WRKY genes， DlWRKY52 was cloned using the leave cDNA of ‘Sijimi longan as the template. Meanwhile， the sequence characteristics， tissue expression patterns， flower and fruit development process expression patterns and subcellular localization were also studied. Bioinformatics analysis indicated that the complete open reading frame （ORF） box of DlWRKY52 was 918 bp， encoding 305 amino acid residues. The amino acid sequence alignment analysis showed that DlWRKY52 contained a typical WRKY domain and a zinc finger structure， belonging to Group Ⅱc. The result of qRT-PCR showed that DlWRKY52 was highly expressed in leave， stem and fruit organs， significantly up-regualted in the pulp 80 days post-anthesis. The transient expression of Arabidopsis protoplasts demonstrated that DlWRKY52 protein was localized to the nucleus， indicating that DlWRKY52， as a typical transcription factor， is localized to the nucleus， and might participate in the regulating of longan floral induction and early fruit development.

Keywords： Dimocarpus longan; WRKY; transcription factor; expression analysis; protein subcellular localization

DOI： 10.3969/j.issn.1000-2561.2020.04.014

龍眼（Dimocarpus longan Lour.）原产于中国华南地区，是无患子科（Sapindaceae）一种重要的热带经济果树。世界上许多热带和亚热带国家均有龙眼的种植和生产，比如澳大利亚及越南、泰国等东南亚国家[1]。中国龙眼的栽培面积和产量一直稳居世界首位，并且在整个世界龙眼产业经济中占有极重要的地位。

龙眼在中国已有2000年以上的栽培历史，我国拥有丰富的龙眼种质资源，同时也积累了先进的栽培、管理技术[2]。然而，实际生产中仍然有很多问题限制着龙眼产业的发展。其中，成花难所导致的产量不稳定是最主要的问题[3]。……