利用转录组分析研究柑橘砧穗间mRNA的移动

发布时间：2018-03-13 06:29

本文选题：嫁接　切入点：生物信息学分析　出处：《华中农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：柑橘作为世界第一大果树品种,由于具有较长的童期,柑橘育种受到了严重阻碍。在实际生产上采用嫁接技术可以有效缩短童期,避免实生繁殖带来的开花晚、始果期迟、盛产期延后等现象。嫁接苗木的始果期可以由实生苗的6-8年缩短到3-5年,而且嫁接繁殖可以根据需要选择不同的砧木,从而改善果实的品质和提高果实产量,使同一批苗木的各项生理生长习性高度保持一致。本实验将克里曼丁橘嫁接于早实枳上,用接穗的母树克里曼丁橘和未嫁接的早实枳作为对照。将它们分别进行转录组测序后,进行生物信息学分析比较。利用接穗和砧木间特异的SNP作为标签对mRNA进行标记,从而研究嫁接后接穗和砧木间mRNA的移动和嫁接后砧穗间基因表达变化。主要结果如下:1、根据转录组测序分析可知,嫁接柑橘的砧木和接穗中有基因存在差异表达。而且基因表达量的变化砧木比接穗更明显。嫁接后的砧木和对照组相比有598个基因表达量显著上调,993个基因表达量显著下调;而接穗嫁接后和对照组相比较只有53个基因表达量显著上调,69个基因表达量显著下调。由此可知嫁接对植株的接穗部分基因表达量的影响小于对砧木部分;2、比对分析发现,在接穗中检测到砧木特异的SNP有563个,砧木中检测到接穗特异的SNP有1268个;接穗中检测到砧木的In Del有3个,砧木中检测到接穗的InDel有33个。结果表明嫁接植株上的砧木和接穗间存在SNP和InDel的变化;而对于嫁接植物而言,无论是SNP还是InDel,砧木的变化总是比接穗的变化大,向下移动的数量总是比向上移动的数量多;3、以SNP作为标签,利用嫁接前后砧穗组织中mRNA的SNP变化判断嫁接植物中mRNA的移动。分析发现存在向上移动SNP的mRNA有452个,存在向下移动SNP的mRNA有960个,上下均有SNP移动的mRNA有16个;结果表明植物嫁接后在接穗和砧木间存在mRNA的移动。而且向上移动的mRNA比向下移动的mRNA少,同时还存在少部分的mRNA可以在砧穗间双向移动;4、将验证后存在可以移动的mRNA的基因分别在克里曼丁橘的根、茎、叶、花中做基因表达量检验。发现基因中mRNA的移动与基因在不同组织中的特异表达并无明显关系。有的基因在花或者根中表达量最高。由于基因表达可能和它参与的功能有关,推断可能有的基因是在叶片或者根部合成但在花中参与生命活动过程,所以才出现这类现象。
[Abstract]:Citrus breeding, as the largest fruit tree variety in the world, has been seriously hindered due to its long childhood period. Grafting technique can effectively shorten the childbearing period and avoid the late flowering and early fruiting due to seed propagation. The initial fruiting period of grafted seedlings can be shortened from 6-8 years to 3-5 years, and grafting propagation can select different rootstocks according to the need, thus improving the quality of fruit and increasing fruit yield. The height of physiological growth habits of the same batch of seedlings was kept consistent. In this experiment, Creman's blueberry was grafted on the precocious trifoliate orange, the mother tree of the scion and the ungrafted precocious trifoliate trifoliate trifoliate orange were used as the control, and they were sequenced respectively. The specific SNP between scion and rootstock was used as the label to mark mRNA. The main results were as follows: 1. According to the analysis of transcriptome sequencing, we studied the shift of mRNA between scions and rootstocks and the changes of gene expression between rootstocks and scions after grafting. There was different gene expression in grafted citrus rootstock and scion, and the change of gene expression in grafted citrus rootstock was more obvious than that in scion. 598 genes expression of grafted citrus rootstock was significantly up-regulated than that of control group, and the expression of 993 genes was down-regulated significantly. However, only 53 genes were significantly up-regulated and 69 genes were down-regulated after scion grafting compared with the control group. Therefore, the effect of grafting on the gene expression of the scion part of the plant was less than that on the rootstock part, the comparative analysis showed that the gene expression of the scion part of the grafted plant was lower than that of the control group. There were 563 rootstock specific SNP detected in scions, 1 268 scion-specific SNP in rootstocks and 3 in Del in scions. 33 InDel of scions were detected in rootstocks. The results showed that there were changes of SNP and InDel between rootstocks and scions of grafted plants, but for grafted plants, the change of rootstocks was always greater than that of scions. The number of downward movement was always more than that of upward movement. The SNP changes of mRNA in panicle tissue before and after grafting were used to judge the mRNA movement in grafted plants using SNP as label. It was found that there were 452 mRNA with SNP moving upward. There were 960 mRNA with SNP moving down and 16 mRNA with SNP moving up and down, the results showed that there was mRNA movement between scion and rootstock after grafting, and the mRNA moved up was less than that moved down. At the same time, there were a few parts of mRNA that could move between rootstocks and ears in both directions. The mRNA genes that could be moved were found in the roots, stems and leaves of Cleimanthus, respectively. It was found that the movement of mRNA in the gene was not related to the specific expression of the gene in different tissues. Some genes expressed the highest amount in the flower or root. Because the gene expression may be related to the function in which it is involved, It is inferred that some genes may be synthesized in the leaves or roots but are involved in the life process in the flower, which is the reason for this phenomenon.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S666

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