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林业科学 ›› 2021, Vol. 57 ›› Issue (5): 53-67.doi: 10.11707/j.1001-7488.20210506

• 论文与研究报告 • 上一篇    下一篇

牡丹秋季开花过程中生理生化变化及DNA甲基化差异

袁雪1,*,袁涛1,刘少丹2   

  1. 1. 北京林业大学园林学院 国家花卉工程技术研究中心 城乡生态环境北京实验室 林木花卉遗传育种教育部重点实验室 花卉种质创新与分子育种北京市重点实验室 北京 100083
    2. 洛阳国际牡丹园 洛阳 471011
  • 收稿日期:2020-06-18 出版日期:2021-07-25 发布日期:2021-07-09
  • 通讯作者: 袁雪
  • 基金资助:
    国家林业局行业标准项目"牡丹综合体"(2018-LY-054);国家林业局重点科学研究项目(2008-10);北京市共建项目专项

Variation in Physiological and Biochemical Properties and DNA Methylation Patterns during Autumn Flowering of Tree Peony(Paeonia Suffruticosa)

Xue Yuan1,*,Tao Yuan1,Shaodan Liu2   

  1. 1. School of Landscape Architecture, Beijing Forestry University National Engineering Research Center for Floriculture Beijing Laboratory of Urban and Rural Ecological Environment Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding Beijing 100083
    2. Luoyang International Peony Park Luoyang 471011
  • Received:2020-06-18 Online:2021-07-25 Published:2021-07-09
  • Contact: Xue Yuan

摘要:

目的: 牡丹花期短而集中,为探究牡丹秋季开花机制,研究牡丹秋季开花过程中赤霉素和DNA甲基化的作用。方法: 以河南洛阳露地栽培的春秋二季开花牡丹品种‘户川寒’为试验材料,2019年9月中旬试验材料自然落叶前,平均分为4组,对照组无脱叶无药剂处理,3个处理组分别经脱叶、脱叶+650 mg·L-1赤霉素(GA3)、脱叶+500 mg·L-1多效唑(PP333)处理,观察记录各处理组与对照在秋季萌芽、开花过程中的生长发育情况,并测定各处理组生理生化及基因组DNA甲基化状态。结果: 1)4组牡丹‘户川寒’均能在秋季萌动、开花,但施加处理能够促进秋季二次萌动开花提前且增加开放整齐度,其中脱叶+650 mg·L-1GA3处理促进萌动和花朵开放作用最佳,在处理后11天时萌动率已达81.4%,并于42天时进入初花期,初花期时间较对照组提前30天。2)脱叶+650 mg·L-1 GA3、脱叶、脱叶+500 mg·L-1 PP333都促进了‘户川寒’秋季较快较整齐地萌芽和生长,且对开花的加速作用依次降低,说明脱叶能够促进芽的萌动和生长,施加GA3具有叠加促进效应,PP333会一定程度抵消脱叶产生的促进效应。脱叶在短时间内发挥了对GA3、GA4含量的抑制作用后,又使芽内GA3、GA4的含量升高而ABA含量下降,施加GA3后加强了GA3、GA4含量升高和ABA含量下降的强度,且延长了GA3、GA4含量上升期,而施加PP333表现出相反的作用。3)芽萌动开花伴随大量淀粉和可溶性糖消耗,高浓度的可溶性糖含量可能有利于芽的萌动。4)MSAP检测结果显示,在整个试验期间‘户川寒’DNA总甲基化的变化范围为57.3%~72.4%,开始萌动前达到DNA甲基化的最高水平,之后逐渐下降。以对照1天时状态为基准,对比其甲基化状态与各处理不同时期甲基化状态发现,处理组甲基化状态变化更活跃,且集中为去甲基化和超甲基化2种模式。各处理组去甲基化率随时间推移增加,且都高于对照组同一时期的去甲基化率,推测去甲基化率高可能更有利于‘户川寒’秋季萌动。结论: 牡丹‘户川寒’能够在秋季自然萌动开花,脱叶能促进内源GA3合成,结合外施GA3的叠加效应,使体内GA3增加并抑制ABA,促进其秋季提前萌动二次开花,且花期整齐,外施PP333一定程度抵消了脱叶引起的内源GA3的合成促进作用。芽从萌动到开花伴随着大量糖类物质消耗,高浓度的可溶性糖含量可能有利于芽的萌动。牡丹‘户川寒’可自我调控相关DNA序列CG位点的甲基化状态,从而诱导其花芽在秋季萌动,施加处理可能会提前触发这一调控过程,其中DNA去甲基化率高更可能促进秋季萌动、开花。

关键词: 牡丹, 秋季开花, 脱叶, 赤霉素, 多效唑, DNA甲基化

Abstract:

Objective: Tree peony (Paeonia suffruticosa) has a short and concentrated florescence, in order to explore the mechanism of autumn flowering, we studied the effects of gibberellin and DNA methylation during autumn flowering of tree peony. Method: Before natural defoliation in the middle September, all plants of the variety (P. suffruticosa 'Togawakan', a spring and autumn flowering variety of tree peony planted in the open field in Luoyang, Henan Province) were divided into 4 treatment groups: defoliation, defoliation + 650 mg·L-1 gibberellin (GA3), defoliation + 500 mg·L-1 paclobutrazol (PP333) processing, and no treatment. Growth performance of the treatment groups and the control was observed and recorded during autumn bud germination and flowering process, and the physiological and biochemical processes and methylation of genomic DNA of the treatment groups were measured. Result: 1) All of the four treatment groups could naturally flower in the autumn, but applying the treatments could promote 'Togawakan' autumn secondary flowering in advance and increase the effect of the flowering uniformity. Particularly, the treatment group of defoliation + 650 mg·L-1 GA3 had the best effect on promoting 'Togawakan' to sprout and flower, with a sprouting rate of 81.4%, 11 days after the treatment, and initial flowering started 42 days after treatment, 30 days earlier than the control group. 2) The defoliation + 650 mg·L-1 GA3, defoliation and defoliation + 500 mg·L-1 PP333 all contributed to fast and neat sprout and growth of the variety 'Togawakan', and the acceleration of flowering decreased in turn, suggesting that defoliation could promote sprout and growth of the buds, applying GA3 has superposition promoting effect, PP333 could offset the promoting effect of defoliation to a certain degree. Defoliation exerted an inhibitory effect on GA3 and GA4 content for a short time at first, then followed by an increase of GA3 and GA4 contents, and a decrease of ABA content in buds. The application of GA3 enhanced the intensity of increased GA3 and GA4 contents and decreased ABA content, and prolonged the rising period of GA3 and GA4 contents, while the application of PP333 showed the opposite effect. 3) Sprouting and flowering were accompanied by the consumption of a large amount of starch and soluble sugars, and a high concentration of soluble sugar may be beneficial to flowering. 4) MSAP test showed that the variation range of total DNA methylation in 'Togawakan' during the whole experiment period was 57.3%-72.4%, reaching the highest level of total DNA methylation before sprouting, and followed by a gradual decrease. The methylation of the control 1 day after treatments, as the baseline was compared with those of the treatment groups in different treatment periods. It was found that the methylation in treatment groups was more actively changing, and the changes were concentrated in two models, demethylation and hypermethylation. The demethylation rate of each treatment group increased with time and was higher than that of the control group in the same period. It was speculated that the high demethylation rate may be more conducive to the bursting of 'Togawakan' in autumn. Conclusion: P. suffruticosa 'Togawakan' could naturally sprout and flower in autumn, defoliation promoted endogenous GA3 synthesis, combined with the superposition effect of exogenous GA3, increased GA3 and inhibited ABA in vivo, promoted its secondary flowering in autumn, and the flowering period was neat. Exogenous PP333 application to some extents counteract the synthesis of endogenous GA3 caused by defoliation. Sprouting to flowering was accompanied by a large amount of sugar consumption, high concentration of soluble sugar might be conducive to bud sprouting. 'Togawakan' can self-regulate the methylation status at locus CG of relevant DNA sequences, thus inducing flower buds to sprout in autumn, and application of the treatments could trigger this regulation process ahead of time, in which high DNA demethylation rate was more likely to promote autumn germination and flowering.

Key words: Paeonia suffruticosa, autumn flowering, defoliation, gibberellin, paclobutrazol, DNA methylation

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