Mobile RNA signalling between rootstock and scion in grafted grapevine
Summary
Objective
The project aims to understand the molecular mechanism and signalling function of a new class of mobile RNA molecules in grafted grapevines. The project will be a continuation of the students’ Masters research where they demonstrated that a recently discovered class of dicistronic RNA transcripts (encoding tRNA and mRNA elements) are conserved across important crop and plant species. Notably, these transcripts were expressed in leaf and berry tissues collected from 22 commercial vineyards in the Barossa Valley (2). Their occurrence in grapevines indicates their potential as signalling messengers as proposed in other plant species.
Background
Grafting is a very important viticultural practice, used to mitigate the impact of environmental stress by improving disease and pest resistance and soil adaptation. Rootstocks also affect scion traits such as yield, vigour and response to soil nutrient conditions. Although the molecular mechanisms for rootstock-scion interactions are complex and poorly understood, there is strong evidence from grapevines and other plant species that RNA transcripts can act as long-distance signalling molecules and coordinate stress responses and growth within the plant body. In the grapevine, extensive exchange of different RNA species has been demonstrated between scions and rootstocks in grafted plants (1).
Research approach
The project will use established Australian rootstock varieties to identify mobile RNAs in grafted plants using a combination of transcriptome and molecular analysis and study their potential signalling function. The student will develop a single nucleotide polymorphism (SNP) database for multiple grapevine rootstock cultivars to use as markers for RNA movement. Beyond the use of the SNP database to identify mobile RNAs, it can also be used in identifying and selecting gene variants that are advantageous in harsh environments such as saline soils and water-limited conditions.
The project will use available genomic and transcriptomic sequencing efforts currently underway at the Waite, UA (ARC Training Centre for Innovative Wine Production) and grape genomes available from the international grapevine genomics repository hosted at UC Davis (grapegenomics.com).
References