Comparative evaluation of regenerable cell systems in ‘White Riesling’ for future genetic modification approaches

Abstract

‘White Riesling’ is the flagship grapevine cultivar of the Rheingau region. However, due to climate change, its cultivation faces increasingly challenging conditions, including drought stress, high solar radiation, and heightened pathogen pressure. Biotechnological approaches provide a powerful toolkit to investigate and potentially modify the underlying physiological responses of the grapevine. Furthermore, anticipated changes in EU regulations are expected to open new opportunities for these technologies.

The Department of Plant Breeding at Geisenheim University possesses extensive expertise in anther-derived somatic embryogenesis across more than 40 varieties, achieving regeneration frequencies of up to 60 % in ‘White Riesling’.

Focusing on this cultivar, various synchronized cell culture systems are available in our lab as starting material for genetic modification: synchronized proembryogenic masses (PEMs), protoplasts (currently under development), and long-term suspension cultures with inducible regenerative potential. To minimize the inherent risk of chimerism, our recent research emphasizes the use of these synchronized materials.

Our in-house expertise in cryopreservation allows for the continuous provision of regenerable material, ensuring that PEMs and suspension cultures are available for transformation regardless of the season.

The objective of this study is to evaluate the suitability of ‘White Riesling’ suspension cultures for genetic modification and to determine whether these cultures indeed represent the most effective starting material compared to our other systems. This is a prerequisite for developing a platform for precise genome editing to support future functional genomics and targeted trait improvement in ‘White Riesling’.