【作者】 李杰；

【导师】 王子成；

【作者基本信息】 河南大学 ， 遗传学， 2016， 硕士

【摘要】 本研究分别对菊花品种“荷花仙子”、“秋水长流”以及“南农红袖”进行短日照处理,观察记录植株高度及开花时间,利用甲基化敏感扩增多态性(MSAP)和高效液相色谱(HPLC)技术对其成花过程中DNA甲基化水平进行检测,分析短日照处理下菊花成花过程中DNA甲基化的动态变化,以揭示短日照处理下DNA甲基化与菊花成花的相关性;利用实时荧光定量PCR技术对“南农红袖”成花过程中开花基因FT以及DNA甲基化去甲基化相关基因的表达量进行分析,从而尝试揭示菊花成花过程中DNA甲基化变化的作用机制。取得的研究结果如下:(1)短日照对菊花株高的影响:短日照处理43 d后,两个品种的处理组株高均显著低于对照组,在短日照处理28 d时,晚花品种处理组株高与对照差异不明显,说明早花品种对短日照的处理更加敏感,进入生殖生长所需要的短日照诱导的时间较短,而晚花品种所需要的短日照诱导时间较长。(2)短日照对菊花成花的影响:短日照处理后,早花品种花蕾出现时间、初花时间及花蕾发育时间与对照相比显著提前。晚花品种花蕾出现时间和初花时间与对照相比显著提前,花蕾发育时间区别不大。(3)短日照处理菊花成花过程中DNA甲基化变化趋势:MSAP和HPLC结果表明,菊花在成花过程中DNA甲基化处于动态变化中,早花品种在开花前DNA甲基化比率主要集中在42.2%-51.3%之间,开花后DNA甲基化比率主要集中在30.5%-44.5%之间。晚花品种在开花前DNA甲基化比率主要集中在43.5%-56.0%之间,开花后DNA甲基化比率主要集中在37.2%-44.9%之间,两个品种在开花前后DNA甲基化都显著降低。(4)短日照处理菊花初花期时DNA甲基化变化:同时期短日照处理组与对照相比DNA甲基化显著降低,但早花品种的下降幅度要大于晚花品种。(5)短日照处理菊花生长过程中FT基因表达分析:进入现蕾期后CmFT表达量明显升高,且现蕾期以及初花期短日照处理组明显高于对照组。(6)短日照处理菊花成花过程中DNA甲基化及去甲基化相关基因表达分析:CmMET1和CmCMT3表达量在菊花成花过程中呈现下降趋势,短日照处理组同时期与对照相比降低幅度更大;CmDRM2的表达量在菊花成花过程中呈现上升趋势,在前三时期对照组表达量低于短日照处理组;去甲基化基因CmDME的表达量在前三个时期表达量变化不大,盛花期时表达升高。更多还原

【Abstract】 This study respectively on Chrysanthemum cultivar "he hua xian zi", "qiu shui chang liu" and "nan nong hong xiu" of short day treatment, observation records of plant height and flowering time. To understand the DNA methylation features of Chrysanthemum during its flowering process, we employed the techniques of methylation sensitive amplification polymorphism(MSAP) and high performance liquid chromatography(HPLC) to detect the DNA methylation level of Chrysanthemum, in the process of flowering. The techniques of real-time fluorescence quantitative PCR were conducted to detect the expression of flowering gene FT and related genes of DNA methylation and demethylation of the Chrysanthemum cultivar "nan nong hong xiu". The results were as follows:(1) Effect of short days on plant height: After 43 days of short day treatment, the Plant height of treatment group was significantly lower than the control. While for late flowering varieties after short day treatment on 28 d, compared with control group, there was no significant difference. That showed that it is more sensitive for early flowering varieties to short-day treatment, and their reproductive growth demanded relatively a short day induced time.(2) Effect of SD on flowering: The time to capituium bud appearance and early blooming from the date of planting were significantly shorter than those of the control for both early and late-flowering cultivar. Capituium development of the early- flowering cultivar significantly accelerated compared with that of the control, which was different with the late-flowering cultivar.(3) DNA methylation changes during flowering under SD treatment: DNA methylation percentage changed dynamically during flower development. For the early-flowering cultivar, DNA methylation was 42.2%-51.3% before capituium bud appearance and 30.5%-44.5% after capituium bud appearance. The respective DNA methylation percentages for the late-flowering cultivar were 43.5%-56.0% and 37.2%-44.9%.(4) DNA methylation changes at early flowering stage following SD treatment: Percentage of DNA methylation of Chrysanthemum decreased significantly during floral development. The decline in DNA methylation was elevated in the early-flowering cultivar compared with that of the late-flowering cultivar.(5) The expression of CmFT in chrysanthemum flowering under short day treatment: The expression of CmFT was significantly increased from squaring, and the treatment group in the period of budding and flowering period was higher than the control.(6) The expression of genes related to DNA methylation and demethylation in chrysanthemum flowering under short day treatment: The expression of CmMET1 and CmCMT3 were decreased in the process of the short-day treatment on Chrysanthemum flowers, and the short day treatment group decreased greater. The expression of CmDRM2 rose in the process of the short-day treatment on Chrysanthemum flowers, the vegetative period and floral bud emergence period of the control group has little change during the first three period. The expression of CmDME has little change in first three periods, and increased in the flowering period.更多还原