Grafting is the union of a bud or stem or even a branch onto the root or stem or branch of another plant, it is termed as a “distant-grafting” when it is carried out among different families, genus or species.

Micro RNA (miRNA), a class of small RNA, is short (20-24 nt), endogenous and non-coding, which is called “master regulators” for its critical role in the most significant biological processes.

Tomato (Solanum lycopersicum) and goji (Lycium chinense) belong to the Solanaceae family, but of different genus. Both of them are medicinally important in human life. In this study, tomato was grafted onto goji to reveal the insight of miRNAs regulation and expression patterns with a distant-grafting system.

Supervised by Prof. WANG Ying, A.B.M. Khaldun and HUANG Wenjun from Wuhan Botanical Garden of Chinese Academy of Sciences comparatively analyzed the miRNA profiles in distant-grafting between tomato and goji through Illumina high-throughput sequencing.

miRNA profile of tomato consisted of 68 known miRNAs and 168 putative novel miRNAs. Compared to the tomato control, a total of 163 of miRNAs were differentially expressed in fruits of grafted tomato, and 123 of them were up-regulated, while only 43 miRNAs were differentially expressed in shoot and 28 of them were up-regulated.

Researcher predicted target genes of these differentially expressed miRNAs and found that they were to be involved in diverse metabolic and regulatory pathways. Venn diagram indicated that three miRNA were possibly transported from stock to scion in a long distance.

This study provides insights into the miRNA profiles of tomato and goji, and a basis for how miRNA signals could exchange between rootstock and scion, and the relevance to diverse biological processes.

The study entitled “Comparative Profiling of miRNAs and Target Gene Identificationin Distant-Grafting between Tomato and Lycium (GojiBerry)” were published in Frontiers in Plant Science.

The study was supported by the National Natural Science Foundation of China, the Scientific Project of Ningxia Agriculture Comprehensive Development, and the Youth Innovation Promotion Association CAS.

Figure: Venn diagram of comparative analysis of miRNA profiles in distant-grafting between tomato and goji (Image by HUANG Wenjun)