Genetic dissection of grape berry ripening control: defining a role for NAC transcription factors

Quality traits of a ripe grapevine (Vitis vinifera L.) berry are acquired during berry development, a long and complex process that involves profound physiological and metabolic changes.
Thanks to the ability to perform genome-wide studies, berry development has been characterized at the level of the transcriptome, showing that the onset of ripening represents a striking metabolic transition associated with a profound transcriptome shift.
The application of different network methods to berry transcriptome datasets has unravelled about 100 genes, named switches, that probably encode key regulators of the transition that drives the berry into the ripening phase.
Among these genes, four NAC transcription factors, VvNAC11, VvNAC13, VvNAC33 and VvNAC60, have been identified.
These four switches together with VvNAC03, a close homologue of tomato NOR gene, were selected for functional characterization.
By performing co-expression analyses on large transcriptomic datasets and by transiently overexpressing each of the five NAC genes in V. vinifera ‘Sultana’, we were able to highlight putative targets that act downstream, as well as transcriptional relationships among some of the NACs themselves, supporting the existence of a complex regulatory network.
Although other functional studies are needed, our findings provide evidence that members of the NAC transcription factor gene family could participate in transcriptomic reprogramming control during berry development.

XII International Conference on Grapevine Breeding and Genetics

S. Zenoni, E. D¿Incà, G.B. Tornielli

Vitis vinifera, NAC transcription factors, onset of ripening, transient expression, transcriptomics

https://doi.org/10.17660/ActaHortic.2019.1248.56