Graft-Transmitted siRNA Signal from the Root Induces Visual Manifestation of Endogenous Post-Transcriptional Gene Silencing in the Scion

Atsushi Kasai,Tianzhong Li,Takeo Harada,Songling Bai,Miguel Blazquez

doi:10.1371/journal.pone.0016895

Atsushi Kasai, Tianzhong Li + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0016895

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Journal: PloS one	Publication Date: Feb 9, 2011
Citations: 74	License type: CC BY 4.0

Affiliation: Hirosaki University, China Agricultural University

Abstract

In plants, post-transcriptional gene silencing (PTGS) spreads systemically, being transmitted from the silenced stock to the scion expressing the corresponding transgene. It has been reported that a graft-transmitted siRNA signal can also induce PTGS of an endogenous gene, but this was done by top-grafting using silenced stock. In the present study involving grafting of Nicotiana benthamiana, we found that PTGS of an endogenous gene, glutamate-1-semialdehyde aminotransferase (GSA), which acts as a visible marker of RNAi via inhibition of chlorophyll synthesis, was manifested along the veins of newly developed leaves in the wild-type scion by the siRNA signal synthesized only in companion cells of the rootstock.

Highlights

Much like the blood vessels of animals, the vascular system of plants provides a pathway by which important nutrients and water can move from one part of the plant body to another
Results and Discussion siRNA-overexpressing transgenic plants To allow visual detection of endogenous post-transcriptional gene silencing (PTGS), we made a glutamate-1-semialdehyde aminotransferase (GSA) gene silencing-inducing construct from NtGSA [14], a useful visible marker in N. tabacum via inhibition of chlorophyll synthesis, which shows high nucleotide sequence homology to the ortholog GSA gene of N. benthamiana (Figure S1)
Quantitative RT-PCR analysis revealed that the levels of NbGSA transcripts were inversely proportional to the siRNA levels in the leaves, while mRNA level of NbSU-s [17] as the control gene was not altered in these plants (Figure S2), indicating that PTGS of GSA expression was clearly dependent upon the level of GSA siRNA

Summary

Introduction

Much like the blood vessels of animals, the vascular system of plants provides a pathway by which important nutrients and water can move from one part of the plant body to another. We report here that companion cell specific production of siRNA signal in only rootstock can introduce a visual manifestation of an endogenous PTGS in the grafted partner, scion.

Results

Conclusion