| Grafting has been used more and more in breeding and improving of economic crops, such as fruit trees and vegetables. Through grafting, plants could not only get better quality of traits and increased yield, but also resistance to disease, salt and low temperature, etc. What is interesting is that more evidences of recent years have indicated that the process of grafting could induce some molecules containing biotic activity, such as RNA communicating between rootstock and scion. Furthermore, the latest report suggested that large fragments of DNA also transport between two plants through grafting. This to some extent provides an strong molecular evidence for the phenomenon of grafting inducing genetic variation found and applied in practice in a long term.DNA methylation as an important epigenetic modification plays an important role in controlling gene expression and maintaining genomic stability in animals and plants. Quantitative evidences suggest that DNA methylation status is changeable when some biotic and abiotic conditions change. Therefore, the question rises whether grafting could induce DNA methylation variation, through which phenotypic variation happen. In this work, we conducted reciprocal grafting between the three important plants of Solanaceae, and analyzed DNA methylation alterations in both rootstocks and scions. The major results are as follow: grafting could cause change of DNA methylation patters, especially a dramatic one to the plants as scion; but the total level of methylation stayed stable; the variation of methylation could be inherited to the progenies at a total or high frequency via meiosis although just a few sites or individuals showed recovery or further change; in the meanwhile, grafting also caused the expression change of methyltransferase slMET1 and slCMT3, the DNA glycosylase/ lyase slROS1, as wll as the important enzymes involving the genesis of small RNA, which was related to the change of methylation. |
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