【摘要】：異三聚體G蛋白(Heterotrimeric G protein),是由a,p和γ三個(gè)亞單位構(gòu)成的蛋白質(zhì)復(fù)合物,它是生物體內(nèi)一類重要的信號(hào)蛋白,參與多個(gè)信號(hào)響應(yīng)過程。水稻中共有4個(gè)G蛋白γ亞基,分別為RGG1、RGG2、GS3和qPE9-1/DEP1,其中GS3是一個(gè)控制籽粒大小的主效QTL,它在調(diào)節(jié)籽粒和器官大小中發(fā)揮負(fù)調(diào)節(jié)子的功能；而qPE9-1是水稻直立穗形成的關(guān)鍵基因,同時(shí)參與水稻氮素和ABA的響應(yīng)。而另外兩個(gè)G蛋白γ亞基RGGI和RGG2尚未進(jìn)行詳細(xì)的功能分析。本研究以RGG2為研究對(duì)象,對(duì)該基因進(jìn)行了表達(dá)分析、亞細(xì)胞定位和組織形態(tài)學(xué)等分析,初步揭示了RGG2的生物學(xué)功能。主要結(jié)果如下：1、RGG2屬于B型G蛋白γ亞基,與RGB1之間存在明顯互作；2、RGG2基因?yàn)榻M成型表達(dá),且其表達(dá)水平比水稻其它3個(gè)G蛋白γ亞基基因RGG1、GS3和qPE9-1高出10倍以上。亞細(xì)胞定位結(jié)果顯示,RGG2蛋白位于細(xì)胞核、細(xì)胞質(zhì)和細(xì)胞膜上；3、過量表達(dá)RGG2基因?qū)е轮仓臧?穗和葉片變短、直立,籽粒短圓,粒重減少,單株產(chǎn)量下降。說明RGG2是這些性狀的負(fù)調(diào)控因子;4、掃描電鏡和組織解剖分析表明,RGG2過量表達(dá)通過抑制細(xì)胞縱向伸長,而使得籽粒變小、節(jié)間變短,但不影響細(xì)胞數(shù)目。細(xì)胞分裂相關(guān)基因的表達(dá)水平在野生型和轉(zhuǎn)基因株系中差異很小,也從側(cè)面驗(yàn)證了這一結(jié)論；5、觀察了日本晴和RGG2過量表達(dá)株系在ABA脅迫下的種子萌發(fā)與幼苗生長情況,發(fā)現(xiàn)RGG2過量表達(dá)系對(duì)ABA的響應(yīng)顯著增強(qiáng)：6.干旱處理表明,RGG2過量表達(dá)株系葉片離體失水率和干旱脅迫下的植株死亡率均顯著低于對(duì)照。以上結(jié)果說明,RGG2作為G蛋白γ亞基,不僅調(diào)控水稻株型、粒型,還參與水稻對(duì)ABA及抗旱脅迫響應(yīng)。
[Abstract]:Heterotrimer G protein (Heterotrimeric G protein),) is a protein complex composed of three subunits of ACP and 緯. It is a kind of important signal protein in organism and participates in many signal response processes. There are four G protein 緯 subunits in rice, RGG1,RGG2,GS3 and qPE9-1/DEP1, respectively. GS3 is a major QTL, that controls grain size. It plays a negative role in regulating grain and organ size. QPE9-1 is the key gene of rice panicle formation, and it is involved in the response of rice nitrogen and ABA. The other two G protein 緯 subunits, RGGI and RGG2, have not been analyzed in detail. In this study, the expression, subcellular localization and histomorphology of RGG2 gene were analyzed, and the biological function of RGG2 was preliminarily revealed. The main results are as follows: 1RGG2 belongs to type B G protein 緯 subunit, and there is obvious interaction between RGG2 and RGB1; (2) the expression level of RGG2 gene was 10 times higher than that of other three G protein 緯 subunit genes, RGG1,GS3 and qPE9-1. The results of subcellular localization showed that RGG2 protein was located in nucleus, cytoplasm and cell membrane, and 3, overexpression of RGG2 gene resulted in plant dwarfing, short panicle and leaf, erect, short round grain, reduced grain weight and decreased yield per plant. The results showed that RGG2 was a negative regulatory factor for these traits, and (4) scanning electron microscopy and histological analysis showed that RGG2 overexpression decreased the grain and shortened the internodes, but did not affect the number of cells by inhibiting the lengthwise elongation of the cells. The expression level of cell division related genes in wild type and transgenic lines was very small, and this conclusion was verified from the side. 5. Seed germination and seedling growth of Nippon and RGG2 overexpression lines under ABA stress were observed. It was found that the response of RGG2 overexpression lines to ABA was significantly enhanced: 6. Drought treatment showed that the rate of water loss in leaves of RGG2 overexpression lines and the plant mortality under drought stress were significantly lower than those of the control. These results suggest that RGG2, as a G protein 緯 subunit, not only regulates the plant type and grain type of rice, but also participates in the response of rice to ABA and drought stress.
【學(xué)位授予單位】：揚(yáng)州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：S511

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