MSH1-induced heritable enhanced growth vigor through grafting is associated with the RdDM pathway in plants

第一作者：Hardik Kundariya

第一单位：内布拉斯加大学

通讯作者：Sally A. Mackenzie

 Abstract 

背景回顾：Plants transmit signals long distances, as evidenced in grafting experiments that create distinct rootstock-scion junctions.

提出问题：Noncoding small RNA is a signaling molecule that is graft transmissible, participating in RNA-directed DNA methylation; but the meiotic transmissibility of graft-mediated epigenetic changes remains unclear.

主要研究：Here, we exploit the MSH1 system in Arabidopsis and tomato to introduce rootstock epigenetic variation to grafting experiments.

结果1-RdDM：Introducing mutations dcl2, dcl3 and dcl4 to the msh1 rootstock disrupts siRNA production and reveals RdDM targets of methylation repatterning.

结果2-嫁接子代生长占优：Progeny from grafting experiments show enhanced growth vigor relative to controls.

结果3-依赖RdDM：This heritable enhancement-through-grafting phenotype is RdDM-dependent, involving 1380 differentially methylated genes, many within auxin-related gene pathways.

结果4-依赖Auxin：Growth vigor is associated with robust root growth of msh1 graft progeny, a phenotype associated with auxin transport based on inhibitor assays.

结果5-遗传多代：Large-scale field experiments show msh1 grafting effects on tomato plant performance, heritable over five generations, demonstrating the agricultural potential of epigenetic variation.

 摘  要 

植物可以长距离传递信号，可以通过嫁接试验来证明，嫁接试验会形成不同的砧木-接穗连接处。非编码小RNA是一种信号分子，并且可以通过嫁接所形成的连接点，参与RNA指导的DNA甲基化，即RdDM；但是，嫁接介导的表观改变能够经过减数分裂后遗传至下一代并不清楚。本文中，作者利用拟南芥和番茄的MSH1系统，在嫁接试验中引入一个砧木的表观变异。将dcl2、dcl3和dcl4突变引入msh1砧木中，会扰乱siRNA的产生，说明甲基化重建的RdDM靶标。相比于对照，嫁接试验的子代表现出增强的生长活力。这种通过嫁接增强的可遗传表型是依赖于RdDM的，涉及1380个差异甲基化的基因，其中许多基因隶属于生长素相关的基因通路。生长优势与msh1嫁接子代的强健根生长相关，而基于抑制试验发现根的强健生长与生长素转运相关。大范围的田间试验显示msh1嫁接对于番茄植株表现的效应可以遗传超过五个世代，说明表观变异具有潜在的农艺应用价值。

 通讯作者 

doi: 10.1038/s41467-020-19140-x

Journal: Nature Communications

Published date: Oct 22, 2020