Lu Mengzhu

Expression characteristics of GFP driven by NAC1 promoter and its responses to auxin and gibberellin

Abstract Abstract A 1050 bp fragment upstream transcription start site of a transcription factor gene NAC1 in Arabidopsis thaliana was amplified and cloned into plasmid pRD420 to construct a green fluorescent protein (GFP) fusion system under the control of NAC1 promoter. Plasmids were introduced into tobacco by Agrobacterium-mediated method to regenerate plants with NAC1-GFP gene, and expression pattern of NAC1-GFP and is responses to auxin and gibberellin (GA) were observed. GFP was found to accumulate specifically in root, and was detected after treatment of auxin, N-1-Naphthylphthalamic acid (NPA, an auxin antagonist) or GA3. It was indicated that the expression of GFP driven by NAC1 promoter was induced not only by auxin but also by Gas, suggesting that NAC1 mediated both the auxin signaling and the Gas signaling involved in lateral roots development. * Supported by National Natural Science Foundation of China (Grant No. 30200169) and Specialized Research Fund for the Doctoral Program of Higher Educa...

毛白杨 PtoWOX4a 基因过表达对次生生长的影响

目的WUSCHEL-related homeobox（WOX）转录因子是植物特有的一类转录因子，参与干细胞维持、侧生器官发育和不定根再生等过程，对植物生长发育有至关重要的作用。本文通过对毛白杨PtoWOX4a基因表达模式的分析和过表达植株表型的观察，研究PtoWOX4a在杨树生长发育中的作用，为全面了解不同物种中WOX基因的作用机制奠定基础。 方法利用qRT-PCR技术分析PtoWOX4a基因在茎顶端分生组织、幼叶、成熟叶、嫩茎、老茎、木质部、韧皮部和根中的相对表达量；利用GUS染色技术对pPtoWOX4a∷GUS转基因植株进行染色，通过GUS信号观察，进一步分析PtoWOX4a在不同组织中的表达模式。对过表达PtoWOX4a植株和对照植株的不定根、茎和叶片进行形态观察和生长指标测定，并通过组织切片对其解剖结构进行观察比较，分析过表达PtoWOX4a对杨树不定根、茎和叶片维管发育的影响。 结果qRT-PCR结果显示，PtoWOX4a在茎中表达量最高，且主要集中在木质部和韧皮部，在根中表达水平次之，而在叶片等其他组织中的表达量较低；pPtoWOX4a∷GUS转基因植株的GUS染色结果与qRT-PCR结果一致，并发现PtoWOX4a主要在根、叶及茎的维管组织中表达。对过表达PtoWOX4a转基因植株表型观察发现，过表达PtoWOX4a抑制了不定根的伸长，3周苗龄的转基因植株不定根长度约为3~4 cm，仅为对照植株的1/3~1/2，不定根直径变粗，根部木质部区域增加。3月苗龄的过表达PtoWOX4a植株变矮，与对照植株相比，株高减少了14%~20%，节间数减少了16%~22%；对第10节间茎段的解剖结构分析发现，过表达PtoWOX4a植株茎部髓心部分变窄，比对照植株减少了10%~20%，木质部区域变宽，比对照植株增加了24%~35%，而形成层区域宽度无明显变化。此外，过表达PtoWOX4a导致植株叶片生长异常，叶片两侧边缘向上卷曲。 结论毛白杨PtoWOX4a基因主要在杨树的维管组织中表达，过表达PtoWOX4a可影响杨树不定根、茎和叶片维管的发育。