第58届Intel ISEF中国参赛项目：银杏D1蛋白基因克隆与幼苗叶片发育时表达的研究
成都市第七中学 高二 杜玮 周陈晨 张典
银杏（Ginkgo bioloba L.）是现存种子植物中最古老的世界著名活化石之一，是中国所特有的第四纪冰川孑遗植物。为了了解银杏幼苗叶片发育时光合基因的表达，及其与细胞核质互作和叶片光合功能实现的关系，本文首次利用RT-PCR和3’RACE方法，扩增银杏D1蛋白基因的编码区（已在Genbank登陆）。对序列测定结果进行生物信息学分析和进化分析；利用分子杂交和免疫印迹方法，对银杏幼苗叶片发育中重要光合基因基因psbA和cab表达的mRNA和蛋白质水平进行了定量的分析。初步探讨了银杏幼苗叶片发育中光合作用基因表达、细胞核质互作的关系。在银杏幼苗发育初期，类囊体膜处于变化中，叶绿素合成加快，组分比例改变和叶绿体的发育状态会不同程度地影响光系统II亚基的代谢水平。
A Study of psbA Gene Cloning and Expression in the Leaves of Ginkgo Seedlings
Plant Sciences
Du Wei, Zhou Chenchen, Zhang Dian 17, No. 7 Middle School of Chengdu City
Ginkgo (Ginkgo biloba L.), one of the oldest living tree species, is the only living member of the gymnosperms division Ginkgophyta. It is considered a “living fossil”, unchanged since the time of dinosaurs, and seen as one of the wonders of the world. Due to such unique characteristics, it has attracted worldwide interest in biomedical and botanic research. However, there have been limited investigations of Ginkgo biloba at the molecular level.
The objective of this project is to understand how the chloroplast-encoded photosynthesis genes are expressed in the leaves of Ginkgo seedlings, and whether the nuclei and chloroplast genetic systems participate in a concerted manner in the early phases of Ginkgo biloba seedling growth. For the first time, we applied RT-PCR and 3’-RACE methods to clone a cDNA fragment of the psbA gene, which encodes the protein D1 of photochemical reaction center, from Ginkgo biloba. Protein sequence showed that the Ginkgo D1 protein is identical to D1 protein found in many other plants. Both Western blot and Northern blot were used to analyze the levels of protein and mRNA of psbA and cab genes. Our project results suggest that the thylakoid membrane goes through constant changes and chlorophyll synthesis speeds up during the early phases of leaf growth. The structural and functional status of chloroplast may influence the expression of photosystem II subunits during ginkgo seedling development.
