發(fā)布時間：2018-06-17 13:02

  本文選題：甜橙 + 細胞��； 參考：《華中農業(yè)大學》2016年博士論文

【摘要】：甜橙[Citrus sinensis(L.)Osbeck]是世界上栽培最廣的柑橘品種類群。因其風味獨特,營養(yǎng)價值高,品種豐富等優(yōu)勢而具有重大的經(jīng)濟價值。甜橙來源于橘和柚的種間雜交,染色體高度雜合。伏令夏甜橙染色體相互易位,極晚熟,少籽,商品性及豐產性良好,是柑橘無籽育種的優(yōu)良親本。隨著測序技術的發(fā)展,細胞遺傳圖譜作為數(shù)量性狀定位,圖位克隆及分子標記輔助育種的重要工具,對育種和遺傳理論研究都具有重要的意義。前人通過花藥離體培養(yǎng),獲得雙單倍體,并進行了全基因組測序。本研究在前人基礎上采用熒光原位雜交結合雙熒光染色技術,創(chuàng)建雜種甜橙及其雙單倍體的分子細胞遺傳學研究平臺,并拓展至柑橘屬及其近緣屬植物的細胞遺傳學研究,主要結果如下:1、甜橙脆性位點的特征。甜橙根尖分生組織細胞常規(guī)染色體制片時發(fā)現(xiàn)染色體片段化現(xiàn)象,結合端粒FISH和CMA/DAPI證實甜橙染色體不易被熒光染料染色的區(qū)域類似于人類和黑麥草上發(fā)現(xiàn)的脆性位點。本研究首次發(fā)現(xiàn)并證實了甜橙染色體上脆性位點的穩(wěn)定存在,位于B型染色體的近中部和D型染色體的近末端的CMA帶型處。Ag-NOR顯示脆性位點定位于具有轉錄活性的45S rDNA區(qū)域,5-m C免疫檢測到脆性位點在有絲分裂中期呈高度甲基化狀態(tài),說明脆性位點的表達是表觀調控的。2、柑橘屬及其近緣屬核型分析和脆性位點分布特征分析。本研究結合前人對柑橘屬及其近緣屬植物的核型特征,補充山金柑等植物的核型分析,發(fā)現(xiàn)脆性位點廣泛地穩(wěn)定地存在于柑橘屬及其近緣屬植物中。盡管不同種植物的45S rDNA位點的數(shù)目和位置各不相同,脆性位點的位置也具有多態(tài)性,但各種二倍體植物中脆性位點的數(shù)目恒定,除了柚類具有3個脆性位點以外,其它種均具有2個脆性位點。脆性位點在雙單倍體和體細胞雜種形成過程中穩(wěn)定遺傳。脆性位點可能和染色體變異及物種進化有關。3、伏令夏甜橙染色體易位。對栽培甜橙及其雙單倍體的核型特征分析發(fā)現(xiàn),栽培甜橙中兩個B型染色體為非同源染色體,他們分別與兩個D型染色體互為同源染色體。該結論修正了前人對甜橙染色體特征的描述,同時從細胞遺傳學水平進一步證實了伏令夏甜橙染色體高度的雜合性。本研究推測這種b型染色體水平上的雜合性來源于發(fā)生在脆性位點處的染色體相互易位,并結合花粉母細胞減數(shù)分裂染色體行為加以佐證。4、甜橙細胞遺傳學圖譜的構建。通過基因組學分析的高度串聯(lián)重復序列cl,中度重復rdna和單拷貝bac為探針,結合cma/dapi的熒光原位雜交技術將甜橙的6個染色體確定,剩下的3個f型染色體根據(jù)染色體的大小和連鎖群的長度加以識別,進而構建了甜橙的細胞遺傳學圖譜。
[Abstract]:Sweet orange (Citrus sinensis L. Osbeck) is the most widely cultivated citrus variety group in the world. Because of its unique flavor, high nutritional value, rich variety and other advantages, it has great economic value. Sweet orange originated from the interspecific hybridization between orange and pomelo, and the chromosomes were highly heterozygous. Volingsia sweet orange is a good parent for seedless breeding because of its translocation of chromosomes, very late maturing, low seed, good commercial and high yield. With the development of sequencing technology, cell genetic map, as an important tool for quantitative trait mapping, map-cloning and molecular marker-assisted breeding, is of great significance for breeding and genetic theory research. Two haploids were obtained by anther culture in vitro, and the whole genome was sequenced. On the basis of previous studies, the molecular cytogenetic research platform of hybrid sweet orange and its dihaploid was established by fluorescence in situ hybridization and double fluorescence staining, and extended to the cytogenetic research of citrus and its relative genera. The main results are as follows: 1, the characteristics of fragile sites in sweet orange. Chromosomal fragmentation was found in the meristem cells of sweet orange root tips. Combining with telomere fish and CMA / DAPI, it was proved that the regions of sweet orange chromosomes not easily stained by fluorescent dyes were similar to the fragile sites found in human and ryegrass. In this study, the stable existence of fragile sites on sweet orange chromosomes was first discovered and confirmed. At the near middle of the B chromosome and the near end of the D chromosome, the. Ag-NOR showed that the fragile site was located in the 45s rDNA region with transcriptional activity, and 5-m C immunoassay showed that the fragile site was highly methylated in the metaphase of mitosis. The results showed that the expression of fragile sites was epithetically regulated. The karyotype and distribution of fragile sites in Citrus and its relative genera were analyzed. Based on the karyotypic characteristics of Citrus and its related genera, we found that fragile sites are widely and stably present in Citrus and its relative genera. Although the number and location of 45s rDNA sites in different species of plants are different, and the location of fragile sites is also polymorphic, the number of fragile sites in various diploid plants is constant, except for three fragile sites in pummelos. All other species have two fragile sites. Fragile sites were stably inherited during the formation of dihaploid and somatic hybrids. Fragile sites may be related to chromosome variation and species evolution. The karyotypic characteristics of cultivated sweet orange and its dihaploid were analyzed. It was found that the two B chromosomes in cultivated sweet orange were non-homologous chromosomes and they were homologous chromosomes with two D-type chromosomes respectively. This conclusion revises the previous description of the chromosomal characteristics of sweet orange and further confirms the heterozygosity of the chromosomal height of Volinghamia sweet orange from the cytogenetic level. In this study, we speculated that the heterozygosity at the level of b chromosome was derived from chromosome translocation at fragile sites, which was supported by the meiotic chromosome behavior of pollen mother cells, and the construction of cytogenetic map of sweet orange. Six chromosomes of Sweet Orange were identified by genomic analysis of high tandem repeats (cll), moderate repeated rdna and single copy bac as probes, and fluorescence in situ hybridization (Fish) of cma/dapi. The remaining 3 f chromosomes were identified according to the size of chromosome and the length of linkage group, and the cytogenetic map of sweet orange was constructed.
【學位授予單位】：華中農業(yè)大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：S666.4

【相似文獻】

相關期刊論文 前1條

1 雷初朝,王德堂,辛曉燕,楊公社,詹鐵生;家豬染色體脆性位點的初步研究[J];西北農業(yè)大學學報;1998年05期

相關博士學位論文 前1條

1 蘭紅;甜橙細胞遺傳學圖譜構建和脆性位點分析[D];華中農業(yè)大學;2016年

相關碩士學位論文 前1條

1 郝穹予;遺傳性脆性X綜合征的細胞與分子遺傳學檢測[D];安徽醫(yī)科大學;2010年

，

本文編號：2031142