The role of DNA methylation in the maintenance of phenotypic variation induced by grafting chimerism in Brassica
作者机构：Department of HorticultureCollege of Agriculture and BiotechnologyZhejiang UniversityHangzhou 310058China Agricultural Experiment StationZhejiang UniversityHangzhou 310058China
出 版 物：《Horticulture Research》 (园艺研究（英文）)
年 卷 期：2023年第10卷第3期
页 面：164-175页
核心收录：
学科分类：0710[理学-生物学] 09[农学] 0902[农学-园艺学] 090202[农学-蔬菜学]
基 金：supported by the National Natural Science Foundation of China(Grant No.32172561) Zhejiang Provincial Basic Public Welfare Research Project(Grant No.LGN19C150012).
主 题：phenotypic maintained grafting
摘 要：Grafting facilitates the interaction between heterologous cells with different genomes,resulting in abundant phenotypic variation,which provides opportunities for crop improvement.However,how grafting-induced variation occurs and is transmitted to progeny remains elusive.A graft chimera,especially a periclinal chimera,which has genetically distinct cell layers throughout the plant,is an excellent model to probe the molecular mechanisms of grafting-induced variation maintenance.Here we regenerated a plant from the T-cell layer of a periclinal chimera,TCC(where the apical meristem was artificially divided into three cell layers–from outside to inside,L1,L2,and L3;T=Tuber mustard,C=red Cabbage),named rTTT0(r=regenerated).Compared with the control(rsTTT,s=self-grafted),rTTT0 had multiple phenotypic variations,especially leaf shape variation,which could be maintained in sexual progeny.Transcriptomes were analyzed and 58 phenotypic variation-associated genes were identified.Whole-genome bisulfite sequencing analyses revealed that the methylome of rTTT0 was changed,and the CG methylation level was significantly increased by 8.74%.In rTTT0,the coding gene bodies are hypermethylated in the CG context,while their promoter regions are hypomethylated in the non-CG context.DNA methylation changes in the leaf shape variation-associated coding genes,ARF10,IAA20,ROF1,and TPR2,were maintained for five generations of rTTT0.Interestingly,grafting chimerism also affected transcription of the microRNA gene(MIR),among which the DNA methylation levels of the promoters of three MIRs associated with leaf shape variation were changed in rTTT0,and the DNA methylation modification of MIR319 was maintained to the fifth generation of selfed progeny of rTTT0(rTTT5).These findings demonstrate that DNA methylation of coding and non-coding genes plays an important role in heterologous cell interaction-induced variation formation and its transgenerational inheritance.
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