目的 对西洋参Panax quinquefolium种子休眠与萌发过程中赤霉素20-氧化酶(GA20ox)基因编码区进行克隆及生物信息学分析。方法 根据西洋参种子转录组的注释信息, 得到9条GA20ox相关序列, 通过比对分析确定了GA20ox的转录本。采用qRT-PCR方法得到西洋参GA20ox(PqGA20ox)的cDNA全长, 并对其编码蛋白进行生物信息学分析。采用实时荧光定量PCR方法检测PqGA20ox基因在根、茎、叶和种子休眠不同时期的表达水平。结果 生物信息学分析表明, PqGA20ox基因全长1 092 bp, 编码363个氨基酸残基, PqGA20ox编码蛋白不含跨膜区, 不含信号肽。qRT-PCR实验结果显示PqGA20ox基因在形态休眠起始期和生理休眠起始期表达量高于其他时期。结论 首次获得PqGA20ox基因的编码区序列, 为进一步研究西洋参种子解除休眠的分子机制奠定基础。

Objective To clone and analyze the coding region of gibberellin 20-oxidase (GA20ox) gene of Panax quinquefolium in seed dormancy and germination process. Methods According to P. quinquefolium seeds transcriptome annotation, one transcript coding of GA20ox was obtained by comparative analysis of nine related unigenes. The full-length cDNA of PqGA20ox was determined by using RT-PCR method. Then the bioinformatic analysis of this gene and encoded protein was performed. The expression level of PqGA20ox in the roots, stems, leaves, and several seed dormancy periods was detected by real time fluorescent quantitative PCR (RT-qPCR). Results Bioinformatic analysis showed that PqGA20ox contained 1 092 bp and encoded 363 amino acids. PqGA20ox encoded protein had neither transmembrane nor signal peptide. The expression level of PqGA20ox was higher in the inset periods of morphological and physiological dormancy than that in the other periods based on RT-qPCR analysis. Conclusion The PqGA20ox gene is cloned for the first time, and will provide a foundation for the dormancy release molecular mechanism of P. quinquefolium.