莲藕根状茎膨大过程中淀粉合成相关基因的表达

Expression of Genes Related to Starch Synthesis During Rhizome Swelling of Lotus Root(Nelumbo nucifera Gaertn)

【目的】通过研究莲藕根状茎膨大过程中基因的表达,挖掘重要的淀粉合成相关基因。【方法】基于转录组测序、数字基因差异表达谱技术以及qRT-PCR方法,研究莲藕(‘美人红’)根状茎膨大过程中淀粉合成相关基因的表达特性。【结果】根状茎膨大始期和中期,淀粉合成缓慢,而膨大后期,淀粉粒明显增大,淀粉含量快速增加。转录组测序结果表明,根状茎膨大过程中34个基因参与了淀粉代谢;差异基因表达谱技术分析显示,LrGBSS、LrSBEI、LrSBEII和LrSBEIII 4个基因在膨大后期表达量显著增加;qRT-PCR结果进一步证明,上述4个基因与根状茎中淀粉合成密切相关。【结论】莲藕根状茎膨大时淀粉积累主要在膨大后期,LrGBSS、LrSBEI、LrSBEII和LrSBEIII 4个基因的表达影响莲藕根状茎淀粉的形成。

[Objective] Critical genes relevant to starch synthesis were explored by studying gene expression during swelling of lotus rhizome. [ Method ] In this study, the changes of starch content and starch granule characteristics were studied during （cv. Mei Ren Hong） swelling period of lotus rhizome. Four important related genes were identified based on transcriptome analysis, digital gene expression profiling and qRT-PCR method. [Result] The result showed that content of the starch was improved more rapidly, and the starch granule was more enlarged at swelling stage than that at initial swelling stage. A total of 34 related genes to starch metabolism were identified during this process. However, only four genes including LrGBSS, LrSBE1, LrSBEII and LrSBEIII were obviously changed their transcriptional level at the swelling stage compared with initial swelling period. The result of qRT-PCR was further proved that LrGBSS, LrSBE1, LrSBE11and LrSBEl11 showed a high correlation with starch synthesis according to their expression characteristics during rhizome development. [ Conclusion] The expression of LrGBSS, LrSBEI, LrSBEII and LrSBEIII is a critical factor to decide the starch content of lotus rhizome.