甜高粱SAI基因的表达与茎秆糖分积累的相关性分析

摘要

[Objective]To better understand the mechanism of sucrose accumulation in sweet sorghum stem, the correlation between sugar content and soluble acid invertase(SAI) gene expression was analyzed by monitoring the expression of SAI in leaves and stems and the sugar content in stems.[Method]The sugar content and expression of SAI gene was investigated by using high performance liquid chromatography (HPLC) and qRT-PCR respectively.[Result]Reducing sugar was the major component at the elongation stage, and sucrose level was lower, then sucrose content was increased significantly at heading and flowering stages, until reached the maximum level at milking and ripening stages, while it declined after ripening. The expression of SAI gene in high-sugar varieties was higher than mid, low, and pith dry varieties in leaves, while it was just the reverse in stems. The sugar content of sweet sorghum at ripening stage was significantly negatively correlated with the expression of SAI gene in stems (r=-0.5971), and was significantly positively correlated with the expression of SAI gene in leaves (r=0.7239).[Conclusion]Sucrose accumulation was correlated with the expression of SAI gene in leaves and stems: a significantly positive correlation between sucrose and the expression of SAI gene in leaves, while a significant negative correlation between sucrose and the expression of SAI gene in stems, the correlation coefficient with leaves was higher than with stem.%[目的]通过检测不同甜高粱品种在各个生育时期叶片和茎秆中 SAI 基因的差异表达量与含糖量，探讨二者之间的相关性，为研究甜高粱糖分积累机制提供理论依据。[方法]高效液相色谱（HPLC）测定甜高粱品种不同生育时期茎秆中的含糖量，qRT-PCR分析叶片和茎秆中SAI基因的表达水平。[结果]拔节期蔗糖含量很低，主要是还原性糖，抽穗和开花期蔗糖含量显著增加，灌浆和成熟期持续增加至最高值，成熟后又有所下降。高糖品种整个生育时期叶片中SAI基因的表达水平高于中糖、低糖和髓干型三类品种，茎秆中SAI基因的表达水平则相反。甜高粱成熟期糖分含量与叶片中SAI基因的表达量呈显著正相关关系，相关系数达0.7239，而与茎秆中的表达量呈负相关关系，相关系数为-0.5971。[结论]甜高粱茎秆蔗糖积累与SAI基因在叶片和茎秆中的表达水平具有相关性，叶片中SAI基因的表达与蔗糖积累正相关，茎秆中SAI基因表达与蔗糖积累负相关，叶片的相关系数高于茎秆。