Rootstock Scion Somatogenetic Interactions in Perennial Composite Plants

In a composite grafted plant, rootstocks control several aspects of scion growth and physiology including yield and quality attributes as well as tolerance to biotic and abiotic stresses. We are interested in understanding the control of floral bud development and overall yield in a perennial crop. Two transcriptome profiling approaches including differential display and 3’ untranslated region sequencing was used to identify the genes that are modulated by the rootstock in the developing floral buds of two scion varieties each grafted onto two rootstock genotypes. Differential display identified 207 putatively differentially expressed gene fragments while 3’UTR sequencing and subsequent analyses revealed 115 differentially expressed transcripts. Additionally, near full length transcriptome sequencing was completed to enable clustering and more effective annotations. Blast analysis revealed that several of the differentially expressed genes were transcription factors or DNA binding domain containing proteins which may be involved in altering the number of floral buds.