Genetic Diversity of Clonally Propagated Grape

Clonal propagation is used to produce genetically identical plants. Grapevine is one such propagated crop; however it is well documented that genetic identity is not necessarily maintained. Several groups have detected the accumulation of somatic mutations in grapevine, which can be observed by the emergence of new ‘sports’ exhibiting phenotypic changes compared to the parental plant. On occasion such phenotypic variations can be maintained by vegetative propagation as new clonal material. An example of this would be the insertion of the Ty3-Gypsy transposable element (TE), Gret-1, into the VvMybA1 promoter, a mutation that has resulted in white-wine varieties.

TEs make up a large proportion of plant genomes and have the potential to alter gene expression via insertion mutagenesis and DNA methylation, contributing to the idea that TEs play a part in adaptive evolution. Clonally propagated grapevine are an ideal crop to investigate such processes.

Here we investigate the accumulation of SNP and TE-derived somatic mutations occurring between chimeric regions of an individual Sauvignon Blanc grapevine that has given rise to a new sport producing red berries. In parallel, we have also investigated the somatic DNA changes between extreme growth points of a separate Sauvignon Blanc grapevine. The tissues sampled have effectively been separated by ~40 years of vegetative growth.

We will present data around TE movement and somatic mutation accumulation not only between individual Sauvignon Blanc clones, but also variation occurring within an individual grapevine.