药用野生稻GBSS基因的系统发育及组织特异性表达

Phylogeny and Tissue-specific Expression of the GBSS Genes in Oryza officinalis

淀粉作为主要的碳水化合物在储藏能量方面发挥至关重要的作用。颗粒结合型淀粉合酶(GBSS)与直链淀粉的合成息息相关。尽管该酶的编码基因已在许多栽培植物中被分离和确定,但有关它们在作物野生近缘种中的序列分歧和表达的研究却相对较少。该研究以药用野生稻(Oryza officinalis)为研究对象,定性和定量地分析了GBSS编码基因的序列特点、与其它植物同源基因的进化关系以及在叶和种子中的表达情况。系统发育分析表明,该酶在禾本科植物中分别由GBSSI和GBSSII基因编码。在药用野生稻中,这2种基因所编码蛋白的氨基酸序列一致性为62%,并且它们在不同器官内呈现时空分化表达,其中GBSSI在种子中超强表达, GBSSII则主要在叶片表达。

Starch is a main kind of carbohydrates and plays a vital role in energy storage. The granule-bound starch synthase (GBSS) is responsible for the synthesis of amylose. Although GBSS genes have been cloned and identified in many cultivated plants, there are only a few cases of studies on non-cultrivated plants. The present study involved qualitative and quantitative analyses on the sequence characteristics, phylogeny, and expression pattern of GBSS genes in Oryza officinalis. Phylogenetic analysis showed that the GBSS was encoded by two GBSS genes (GBSSI and GBSSII) in all species of Poaceae. In O. officinalis, the two genes shared 62% amino acid identity and displayed different expression patterns in different organs. GBSSII expression was higher in leaves than seeds, whereas GBSSI was mainly expressed in seeds, which suggests divergent spatial expression of the two genes in this wild rice.