复幼促进核桃不定根发生的DNA甲基化机制探讨  

DNA Methylation Mechanism of Adventitious Roots of Walnut Promoted by Rejuvenation

作　　者：李莉[1,2] 宋晓波 常英英[1] 张俊佩[1] 徐慧敏[3] 裴东 LI Li;SONG Xiaobo;CHANG Yingying;ZHANG Junpei;XU Huimin;PEI Dong(State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration, Research Institute of Forestry Chinese Academy of Forestry, Beijing 100091, China;2Chinses Society of Forestry, Beijing 100091, China;3Forestry Bureau of Luoning County, Luoyang, Henan 471700, China)

机构地区：[1]林木遗传育种国家重点实验室,国家林业局林木培育重点实验室,中国林业科学研究院林业研究所,北京100091 [2]中国林学会,北京100091 [3]河南省洛宁县林业局,河南洛阳471700

出　　处：《西北植物学报》2020年第7期1135-1147,共13页Acta Botanica Boreali-Occidentalia Sinica

基　　金：中央级公益性科研院所基本科研业务费专项(CAFYBB2018SY006);国家自然科学基金(31672126)。

摘　　要：该研究以核桃的复幼和成龄插穗为材料,通过甲基化修饰依赖性内切酶测序技术(MethylRAD-Seq),在全基因组水平上检测成龄与复幼插穗中DNA甲基化位点分布特征,进一步对复幼处理前后插穗中差异甲基化位点相关基因的表达情况进行分析。结果显示:(1)复幼处理可显著降低核桃插穗的DNA甲基化水平。(2)功能富集分析结果显示,差异甲基化位点相关基因主要参与油菜素内酯信号转导、次级代谢产物生物合成和木质素生物合成等功能,参与光合作用、MAPK(mitogen-activated protein kinase,MAPK)信号通路、果糖和甘露糖代谢、cAMP(cyclic AMP,CAMP)信号途径和苯丙烷生物合成等代谢通路。(3)qRT-PCR分析结果显示,复幼处理前后,不定根发生的关键调控基因NAC1、ARF5、ARF6和WRKY22在复幼和成龄材料中具有不同的表达模式。研究认为,复幼处理降低了核桃插穗中基因组DNA的甲基化水平,进而影响不定根发生过程关键功能基因的表达,可能是复幼调控核桃不定根发生能力的重要途径。Recovery the juvenile characteristics of mature wood by rejuvenation treatment is an important approach to improve the adventitious rooting capacity of difficult-to-root woody plants.However,the mechanism of rejuvenation is still unclear.In this study,rejuvenated and mature cuttings of walnuts were used as materials,DNA methylation pattern of both cuttings was detected at the genome-wide level by methylation modification-dependent endonuclease sequencing technology(MethylRAD-Seq).And then,the expression level of genes which is related to differential methylation sites were analyzed.The results showed that:(1)rejuvenation treatment could significantly reduce the level of DNA methylation in walnut cuttings.(2)Functional enrichment analysis showed that genes related to differential methylation sites were mainly involved in brassinolide signal transduction,secondary metabolite biosynthesis and lignin biosynthesis.They participated in metabolic pathways such as photosynthesis,MAPK(Mitogen-activated protein kinase,MAPK)signaling pathway,fructose and mannose metabolism,cAMP(cyclic AMP,CAMP)signaling pathway and phenylpropane biosynthesis pathway.(3)qRT-PCR analysis showed that key regulatory genes(NAC1,ARF5,ARF6 and WRKY22)had different expression patterns in rejuvenated and adult materials.It indicated that the rejuvenation treatment affected the expression of core regulatory genes of adventitious root formation,through reduced the genomic DNA methylation level in walnut cuttings.It may be an important regulatory pathway for rejuvenation to regulate adventitious root formation in walnut.

关 键 词：核桃 复幼 不定根 发育阶段转变 Methyl-RAD测序 

分 类 号：Q789[生物学—分子生物学]