青杨全同胞异源三倍体群体表观遗传变异研究

发布时间：2018-03-28 13:14

本文选题：青杨异源三倍体群体　切入点：DNA甲基化　出处：《北京林业大学》2016年博士论文

【摘要】：基因的表达受表观遗传修饰和转录后调控因子的调控,开展青杨异源三倍体群体形成过程中表观遗传变异和转录后调控因子的变异研究,可以从不同层次探讨青杨三倍体生长优势形成的分子机制。本研究以来源于不同类型2n雌配子[FDR型(First division restitution)、SDR型(Second division restitution)、PMR型(Post-meiotic restitution)]的全同胞青杨异源三倍体群体(triploid-F, triploid-S, triploid-P)和其同亲本的杂种二倍体群体(diploid-F1),及其母本‘哲引3号杨’[(P. pseudo-simonii)× (P. nigra L. var. italica)]、父本‘北京杨’(P. ×beijingensis)为研究材料,采用群体取样的策略,利用甲基化敏感扩增多态性(Methylationsensitive amplification polymorphism, MSAP)标记和小RNA高通量测序技术,从群体水平分析了青杨异源三倍体群体中全基因组DNA甲基化变异和miRNA表达变异,综合评价了杂交和多倍化对DNA甲基化变异和niRNA表达变异的影响,初步探讨了表观遗传修饰和转录后调控因子在青杨异源三倍体速生优质等性状形成过程中的作用。主要研究结果如下：(1)杂交和多倍化可导致青杨异源三倍体群体DNA甲基化水平和模式发生变异。3个异源三倍体群体的总甲基化水平都低于其亲本和二倍体群体,其中,triploid-F群体的总甲基化水平为19.88%,显著低于triploid-S群体和triploid-P群体(21.77%和21.66%)；而diploid-F1群体的总甲基化水平为23.93%,显著高于亲本和异源三倍体群体,且4个子代群体中的DNA甲基化均以全甲基化类型为主。此外,绝大多数检测位点的DNA甲基化模式可以由亲本稳定的遗传给子代群体,但一些位点也发生了变异,变异类型以超甲基化为主。其中,triploid-F群体发生超甲基化模式变异的频率最低,为2.04%,而diploid-F1群体发生超甲基化模式变异的频率达到4.97%,显著高于3个异源三倍体群体,但3个异源三倍体群体发生去甲基化的频率均高于二倍体。由于青杨异源三倍体群体发生超甲基化的的频率低于二倍体群体,且去甲基化频率高于二倍体群体,导致其整体甲基化水平显著低于二倍体群体,进而引起某些基因表达水平的相对升高,推测这可能是青杨异源三倍体生长性状优于杂种二倍体的原因之一。(2)亲本‘哲引3号杨’和‘北京杨‘之间存在差异表达的miRNA,主要以母本中表达上调为主,其中29个miRNA在母本中特异表达；青杨异源三倍体群体和杂种二倍体群体中miRNA的表达具有明显的偏好性,即miRNA表达在子代与父本间的差异远大于与母本间的差异。而且,各子代群体中还检测到亲本表达水平显性的miRNA,母本显性的niRNA数量远大于父本显性的miRNA数量；母本显性的miRNA主要与植物的生长发育过程相关,而父本显性的miRNA主要与植物胁迫响应和基因组稳定性有关。三个青杨异源三倍体群体与杂种二倍体群体相比,所有检测到的miRNA(2273个)的表达水平在不同倍性群体间均无显著差异；三个来源于不同诱导途径的异源三倍体群体间的niRNA表达也无显著差异。本研究结果表明,青杨异源三倍体群体miRNA的表达无剂量效应,导致miRNA对靶基因的负调控作用相对减弱,是青杨异源三倍体生长优势形成的重要分子机制之一。(3) miRNA在高生长突出的青杨异源三倍体和杂种二倍体植株中的表达与父本间的差异均显著大于与母本间的差异,表现出明显的偏好性,且子代样本中miRNA的表达变异主要以上调为主。四组高生长突出的子代样本中表现出母本显性的miRNA也显著多于父本显性miRNA,母本显性的niRNA主要参与木质素合成和分解代谢、多细胞器官发育等与植物生长发育相关的生物学过程,而父本显性的miRNA主要与植物营养生长向生殖生长的转变,花器官的发育、抵抗外界刺激等过程相关。需要特别指出的是,在3个异源三倍体高生长突出的植株中,还检测到一些表达被显著抑制的miRNA,主要与植物次生细胞壁的合成和积累,细胞内大分子的代谢活动等相关,推测部分niRNA的非加性表达也可能与异源三倍体突出的生长优势有关。此外,三组高生长突出的青杨异源三倍体植株与杂种二倍体植株间miRNA的表达也均无显著差异,该结果进一步验证了青杨异源三倍体中miRNA的表达无剂量效应的特点。
[Abstract]:Gene expression by regulating factor table epigenetic modification and post transcriptional regulation factors, variation of the formation process of developing poplar allotriploid group epigenetic variation and post transcriptional mechanisms from different levels of poplar triploid growth advantage can be formed. This study originated from different types of 2n female gametes ([FDR First division restitution (Second), SDR division restitution), PMR (Post-meiotic restitution)] full sib poplar allotriploid (triploid-F, triploid-S group, triploid-P) and its parent hybrid diploid group (diploid-F1), and its female parent "Zhe Yang [3 '(P. * (P. nigra pseudo-simonii) L. var. italica)], the male" Beijing Yang "(P. * beijingensis) as research materials, using the group sampling method, by using the methylation sensitive amplified polymorphism (Methylationsensiti Ve amplification polymorphism, MSAP) markers and small RNA high-throughput sequencing technology, from the population level analysis of variation of whole genome DNA methylation and miRNA expression of poplar allotriploid group, comprehensive evaluation of the effects of variation of hybridization and polyploidy on the expression variation of DNA methylation and niRNA, discussed the epigenetic modification and transcription after the regulatory factors in the fast-growing poplar allotriploid quality traits in the process of formation. The main results are as follows: (1) hybridization and polyploidization can lead to the total methylation level of poplar allotriploid group DNA methylation level and pattern variation of.3 allotriploid population were lower than that of their parents and diploid populations, among them, the total methylation level of triploid-F group was 19.88%, significantly lower than that of triploid-S group and triploid-P group (21.77% and 21.66%); and group diploid-F1 total methylation The level is 23.93%, significantly higher than that of their parents and allotriploid groups, and 4 sub populations in DNA methylation with full methylation types. In addition, the DNA methylation pattern of majority of testing sites may be stable by genetic parents to offspring groups, but some sites with the variation of variation type hypermethylation. Among them, triploid-F group has the lowest frequency, hypermethylation pattern variation is 2.04%, while the diploid-F1 group showed hypermethylation pattern mutation rate reached 4.97%, significantly higher than 3 allotriploid groups, but the 3 groups of allotriploid demethylation frequency were higher than diploid. Due to hypermethylation the group of poplar allotriploid frequency lower than the diploid group, and the methylation frequency is higher than the diploid group, resulting in the overall methylation level was significantly lower than the diploid group, and Due to some relative increase in gene expression, speculated that this may be one of the reasons for poplar growth traits than allotriploid hybrids were diploid. (2) the parents' 3 Zhe Yang Yang "and" Beijing "the differences between the expression of miRNA, mainly in the female as the main expression, one of the 29 miRNA in the female specific expression; the expression of miRNA and diploid hybrid poplar allotriploids groups in the group have a clear preference, namely the expression of miRNA in the difference between offsprings and far greater than the differences between parents and offspring. Moreover, the group also detected parental dominant expression level of miRNA, the number of miRNA niRNA number of female dominance is far greater than the male dominant; female dominant miRNA mainly in plant growth and development process, and the male dominant miRNA and plant stress response and genome stability. Three poplar Compared with groups of allotriploid hybrids were diploid populations, all detected miRNA (2273) the expression level had no significant difference in different ploidy groups; three from different ways of inducing allotriploid groups niRNA expression was no significant difference. The research results show that no dose effect expression of heterologous poplar the triploid group miRNA, resulting in relatively weak negative regulatory effect of miRNA on target gene, is one of the important molecular mechanism of poplar allotriploids growth advantage formation. (3) differential expression of paternal miRNA in high growth prominent poplar allotriploid and hybrid diploid plants in between were significantly greater than the differences between the performance and the female parent. A clear preference, and the expression variation of miRNA progeny in the sample above the main tone based. Four groups of high growth of outstanding progeny samples showed maternal dominant miRNA also significantly With more than the male dominant miRNA, maternal dominant niRNA mainly involved in lignin biosynthesis and catabolism, multicellular organ development and biological processes related to plant growth and development, while the male dominant miRNA main vegetative growth to reproductive growth, floral organ development, resistance to external stimulation in particular process. In 3, the high growth of allotriploid prominent plants, also detected some expression was significantly inhibited by miRNA, and the main plant secondary cell wall synthesis and accumulation of macromolecules within the cell metabolism and other related activities, the growth advantage of non additive expression that niRNA may also be allotriploid prominent. In addition, the expression of three groups of high growth prominent poplar allotriploid plants and hybrid diploid plants of miRNA also showed no significant difference, the results further validate the poplar The expression of miRNA in the heterologous triploid is characterized by no dose effect.

【学位授予单位】：北京林业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S792.113

【相似文献】