黄小龙 陈婷婷 张琴琴 莫佳佳 龚盼琴 闫慧清

摘 要：為了观察刺梨果实的果刺细胞学发育过程，该研究以刺梨‘贵农5号的cDNA为模板，通过RACE克隆获得刺梨中与拟南芥表皮毛形成GL2的同源基因RrGL2，并对该基因进行生物信息学分析和表达分析。结果表明：（1）刺结构在花芽形成早期基部内的细胞首先不断分裂，向外继续发育，中部的细胞变细、变长形成“针”状结构，顶部的细胞逐渐木质化使刺变硬，形成果刺。（2）通过RACE扩增得到RrGL2的cDNA全长2 292 bp，编码763 aa氨基酸。（3）RrGL2具有Homeodomain同源结构域和StAR磷脂酰胆碱转移蛋白的结构域，RrGL2与其他物种编码的GL2氨基酸同源性高度相似，并且系谱树分析揭示刺梨RrGL2和野草莓的GL2密切相关。（4）qRT-PCR分析表明，RrGL2在茎和果实中的表达水平高于其他组织，在花后7周果刺中的表达最高，是3周和5周果刺中的7.87倍和2.10倍。综上结果发现RrGL2的功能与果刺的形成发育密切相关，该研究为刺梨中刺形成的分子机制和育种提供了理论基础。

关键词：刺梨，表皮毛，果刺，RrGL2，基因表达

中图分类号：Q949.45文献标识码：A

Abstract：In order to observe cytological development of prickles in fruits of Rosa roxburghii， R. roxburghii GLABROUS 2 （RrGL2），a prickle-development related AtGL2 homology gene，was isolated from ‘Guinong 5 and relative biological information and expression were analyzed in this paper. The cytological development of fruit thorn of Rosa roxburghii was observed by paraffin section. Leaves of Rosa roxburghii was used to synthesize cDNA based on the manufacturers instructions of RACE. Subsequently RrGL2 was made relative informatics analysis and the gene expression level was eva-luated. The results were as follows：（1） The base cells continuously divided at the early stage of flower bud，then outward developed. The middle cells continued to become thinner and longer to form a “needle” structure. In the early stage of flower bud formation，the cells in the base of the thorn structure first divided continuously and continued to develop outwards. The cells in the middle became thinner and longer，forming a “needle” structure. The lignification gradually was observed at the top cells to make the prickles hard. （2） The full lengths of RrGL2 was 2 292 bp by RACE，encoding 763 amino acids. （3） The RrGL2 had a structure of Homeodomain and StAR phosphatidylcholine transfer protein，which is likely to regulate the development of Rosa roxburghii prickles. Then，a search for homologous species in the NCBI databases revealed a high similarity of amino acid homology encoded by the RrGL2 with other Rosa species，and phylogenic analysis revealed a close relationship of structure domains between Rosa roxburghii and Fragaria vesca. （4） Finally，real-time PCR analysis showed that the relative expression value of RrGL2 in fruit prickles after seven weeks after flowering was the highest，almost respectively 7.87 times and 2.10 times than that during three weeks and during five weeks after flowering. RrGL2，a prickles-forming gene acted to regulate the morphology and development of prickles. Therefore，the function of RrGL2 is closely related to thorn formation. These results could provide theoretical basis for thorn formation and development.

Key words：Rosa roxburghii，trichomes，prickles，RrGL2，gene expression

刺梨（Rosa roxburghii）为蔷薇科多年生落叶灌木缫丝花的果实，因具有良好的风味和较高的营养价值深受消费者喜爱，在中国西南地区尤其是贵州省大规模种植。果实中因含有一些酚类化合物、抗氧化物等（Van et al.，2008），可作为放射性保护剂和肿瘤抑制剂（Liu et al.，2012;Xu et al.，2014）;同时也是果汁和干果的重要原料。然而，刺梨果实密披果刺，果刺对水果采摘、食品加工、田间和果园管理造成不便。近年来随着园艺业的发展，植物果刺已经引起越来越多的关注。……