發(fā)布時間：2018-02-20 04:21

  本文關(guān)鍵詞： 番茄 GWAS GRAS2 果實 發(fā)育 馴化　出處：《華中農(nóng)業(yè)大學(xué)》2017年博士論文　論文類型：學(xué)位論文

【摘要】：番茄(Solanum lycopersicum)因其較短的生長周期、穩(wěn)定的遺傳特性、較小的基因組信息等優(yōu)點,被視為研究漿果類果實發(fā)育的模式作物之一。通過利用傳統(tǒng)的雙親連鎖圖定位的方法,已經(jīng)鑒定出多個調(diào)控番茄果實重量的基因。但傳統(tǒng)QTL定位的方法存在著不足之處,對已定位的果重QTL區(qū)域無法進(jìn)行更細(xì)致的功能基因的發(fā)掘與驗證。全基因組關(guān)聯(lián)分析方法,是對傳統(tǒng)定位方法很好的補(bǔ)充,極大的提高番茄果重QTL區(qū)域內(nèi)關(guān)鍵基因的定位與克隆工作。本研究通過對288份番茄種質(zhì)群體進(jìn)行番茄果實重量性狀的關(guān)聯(lián)分析,鑒定出番茄GRAS2基因能調(diào)控果實的重量。主要研究結(jié)果如下:1.在對番茄果重性狀的關(guān)聯(lián)分析中,共發(fā)現(xiàn)9個信號與群體番茄果重的具有顯著的相關(guān)性。其中,有4個顯著信號與之前報道的lc、fw3.2、fascinated、fw11.3基因位點緊密相關(guān),說明本研究中關(guān)聯(lián)數(shù)據(jù)可靠、模型合理、分析結(jié)果準(zhǔn)確。鑒于此,我們進(jìn)一步對檢測到的5個信號進(jìn)行了定位,發(fā)現(xiàn)它們分別位于fw1.2、fw6.3、fw7.3、fw11.1、fw11.2區(qū)間附近,這為我們下一步克隆番茄果重QTL基因提供依據(jù)。2.通過QTL fw7.3的顯著信號分析并結(jié)合轉(zhuǎn)基因驗證,發(fā)現(xiàn)距離顯著SNP63492244的GRAS2可能為fw7.3關(guān)鍵功能基因。在其干涉植株中果實出現(xiàn)明顯發(fā)育受阻,表型出花器官變小、子房的初始發(fā)育受阻、果皮的厚度變薄、細(xì)胞皺縮、種子的數(shù)目變少等形態(tài)改變。同時,干涉植株還出現(xiàn)植株變矮。說明GRAS2為植物體正常發(fā)育所需的功能基因。3.轉(zhuǎn)錄分析表明,GRAS2在盛花期的子房具有相對高的表達(dá)。同時,在發(fā)育種子的外包膜上具有持續(xù)的表達(dá)。說明GRAS2特異的表達(dá)時期和表達(dá)部位對果實初始發(fā)育是至關(guān)重要的。GRAS2參與植物體內(nèi)赤霉素合成途徑,GRAS2干涉植株體內(nèi)的內(nèi)源赤霉素誘導(dǎo)子房發(fā)育過程受到影響,導(dǎo)致最終果實的發(fā)育受阻。4.分子遺傳進(jìn)化分析顯示,GRAS2在關(guān)聯(lián)群體的基因型分布與群體果實的進(jìn)化趨勢具有相似性。分析發(fā)現(xiàn),GRAS2在番茄早期馴化從野生番茄到櫻桃番茄的過程中發(fā)生重大的變異,而從櫻桃番茄到栽培番茄的改良過程變異幅度較小現(xiàn)象。5.其他茄果類蔬菜作物中,包括辣椒、茄子,其GRAS2具有相似度極高的同源基因,可能具有相似的調(diào)控機(jī)制�；贕RAS2在番茄果實發(fā)育的作用機(jī)制,為揭示其他茄科作物果實發(fā)育的機(jī)制具有重要的參考作用。
[Abstract]:Solanum lycopersicum is regarded as one of the model crops to study berry fruit development because of its short growth cycle, stable genetic characteristics and small genomic information. Several genes have been identified to regulate tomato fruit weight. However, the traditional QTL mapping method has some shortcomings, so it is impossible to identify and verify more detailed functional genes in the located fruit weight QTL region. It is a good supplement to the traditional mapping method and greatly improves the mapping and cloning of the key genes in the QTL region of tomato fruit weight. In this study, the correlation analysis of tomato fruit weight traits was carried out among 288 tomato germplasm populations. Tomato GRAS2 gene was identified to regulate fruit weight. The main results are as follows: 1. In the correlation analysis of fruit weight traits of tomato, 9 signals were found to be significantly correlated with tomato fruit weight. Four significant signals were closely related to the previously reported loci of lcfw3.2fascinated fw11.3 gene, indicating that the data in this study are reliable, the model is reasonable and the analysis results are accurate. In view of this, we further localize the five signals detected. It was found that they were located in the region of fw1.2 / fw6.3fw7.3 / fw11.1fw11.2 respectively, which provided the basis for cloning QTL gene of tomato fruit weight in the next step. 2. The significant signal analysis of QTL fw7.3 combined with transgenic verification was carried out. It was found that the GRAS2 with significant distance from SNP63492244 might be the key gene of fw7.3. The fruit development was blocked obviously, the flower organs became smaller, the initial development of ovary was blocked, the thickness of pericarp was thinned and the cells shrank in the intervening plants. At the same time, the number of seeds decreased and the number of seeds decreased. Meanwhile, the interference plants also appeared to be shorter. The results showed that GRAS2 was the functional gene required for the normal development of plant. 3. Transcriptional analysis showed that the expression of GRAAS2 was relatively high in the ovary of flowering stage. At the same time, the expression of GRAS2 in the ovary of flowering stage was relatively high. There is persistent expression on the outer membrane of the developing seeds. It is suggested that the specific expression period and expression site of GRAS2 are very important for the initial fruit development. GRAS2 is involved in the biosynthesis pathway of gibberellin in plants. The process of gibberellin induced ovary development was affected. The molecular genetic evolution analysis showed that the genotype distribution of GRAS2 in the associated population was similar to the evolutionary trend of the fruit of the population. It was found that GRAAS2 was domesticated from wild tomato to cherry in the early stage of tomato. There was a major mutation in the tomato process, However, the variation range of improvement process from cherry tomato to cultivated tomato was small. 5. Other tomato vegetable crops, including capsicum and eggplant, had high similarity homologous genes in GRAS2. Based on the mechanism of GRAS2 in tomato fruit development, it has an important reference role in revealing the mechanism of fruit development of other eggplant crops.
【學(xué)位授予單位】：華中農(nóng)業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：S641.2

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本文編號：1518753