Location: Grape Genetics ResearchTitle: Messenger RNA exchange between scions and rootstocks in grafted grapevines Author
|Mao, Linyong - Boyce Thompson Institute|
|Jittayasothorn, Yingyos - Former ARS Employee|
|Kang, Youngmin - Former ARS Employee|
|Jiao, Chen - Boyce Thompson Institute|
|Fei, Zhangjun - Boyce Thompson Institute|
Submitted to: Biomed Central (BMC) Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2015
Publication Date: 10/19/2015
Citation: Yang, Y., Mao, L., Jittayasothorn, Y., Kang, Y., Jiao, C., Fei, Z., Zhong, G. 2015. Messenger RNA exchange between scions and rootstocks in grafted grapevines. Biomed Central (BMC) Plant Biology. 15:251.
Interpretive Summary: Although grafting has been practiced in many fruit species for centuries, how genetically the graft partners interact with each other to produce vigorous grafted plants is largely unknown. In this study, we discovered extensive exchanges of messenger RNAs (a form of genetic information carrier) between scions and rootstocks in grafted grapevines, which could be the key genetic basis of superior performance of grafted plants. We found that the relative transmission rates of mRNAs were generally low. However, more than three thousands of grape genes involved in such large-scale exchanges of genetic information between scions and rootstocks underscored the underlying importance of the phenomenon. We further revealed that such exchanges could be affected by genetic, genotypic, environmental factors and possibly controlled by different mRNA movement mechanisms. While many biological processes and mechanisms involved in such mRNA movement are yet to be elucidated, one obvious benefit from such exchange of mRNAs between two genetically distinct graft partners would increase diversity of the mRNA pool accessible to both scion and rootstock in a graft. Such diverse pool of mRNAs in turn can make the grafted plants more productive and adaptive to various biotic and abiotic conditions through complementation and synergistic interactions of the two genetic systems from scions and rootstocks.
Technical Abstract: We demonstrated the existence of genome-scale mRNA exchange in grafted grapevines, a woody fruit species with significant economic importance. By using diagnostic SNPs derived from high throughput genome sequencing, we identified more than three thousand genes transporting mRNAs across graft junctions in grafted grapevines grown in the in vitro and field conditions. These genes were involved in many diverse biological processes such as responses to stress and stimulus, signal transduction, and biosynthesis. Field-grown mature grafts had much fewer genes transmitting mRNAs than the in vitro young grafts (987 vs. 2,679). These mobile mRNAs could move directionally or bi-directionally between scions and rootstocks. The mRNA transmission rates of these genes were generally low, with about 65% in the field grafts and 75% in the in vitro grafts having transmission rates lower than 0.01. Furthermore, genotypes, graft combinations and growth environments had impact on the directions of mRNA movement as well as the numbers and species of mRNAs being exchanged. Moreover, we provided evidence for the presences of both passive and selective mechanisms underlying long distance mRNA trafficking in grafted grapevines.