Unraveling the Role of Lenticels in Sunburn Resilience of Grapevine Berries

• Applicant: Dr. Nagarjun Malagol
• Subject Area: Plant Breeding and Plant Pathology ; Plant Physiology
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 571278964

Climate change significantly impacts viticulture, particularly in traditionally cool-climate regions such as Germany. The rise in temperatures, the occurrence of extreme heat events, and alterations in precipitation patterns are exacerbating both biotic and abiotic stress in vineyards. Among the abiotic stressors, sunburn on grape berries has emerged as a critical threat to yield and fruit quality. Sunburn results from a combination of heat, solar radiation, and UV stress, leading to berry browning, dehydration, and compositional changes that impair wine quality and reduce marketability. Although varietal differences in sunburn susceptibility are well-documented, the physiological traits underlying resilience remain inadequately understood. Recent observations suggest that lenticels, microscopic pores on the berry pedicel may play an underexplored role in oxygen diffusion, transpiration, and berry cooling under heat stress. However, this potential function remains speculative and has not yet been systematically investigated in grapevines. This project aims to explore lenticels as a potential resilience mechanism against sunburn. We will investigate their physiological role in oxygen regulation and berry cooling, and determine whether lenticel traits correlate with reduced sunburn severity. Furthermore, we aim to identify genetic factors underlying lenticel development, supporting future breeding of more climate-resilient grapevine cultivars. This project will pioneer a new line of research into lenticel-based resilience mechanisms in grapevine berries. By linking lenticel traits to oxygen homeostasis, sunburn tolerance, and genetic control, the project will deliver insights for viticulture under climate stress. The results will inform physiological understanding and marker-assisted selection, contributing to sustainable grape production in future climates.

• DFG Programme: Research Grants