Ome Wide Studies Of Grapevine Fruit Composition And Responses To Agro Environmental Factors In The Era Of Systems Biology PDF Download

Environmental stimuli from different abiotic and biotic origins can influence grapevine physiology and fruit chemistry at different scales, with downstream effects on wine chemistry and quality. These stimuli can originate at the macroscale (region), mesoscale (vineyard), and microscale (plant), and can interact in their influence upon wine grape production. Wine grape growers are limited in their ability to control factors at the macro- and mesoscale, while the microscale is more easily managed to ensure quality grape production; for example, while grape growers cannot change regional weather conditions or trends, various management methods can be implemented to influence grapevine physiology and fruit chemistry for quality wine production. The goal of this dissertation is to address this theme and investigate how different abiotic and biotic stimuli may influence grapevine physiology and fruit chemistry at different scales. This dissertation includes four chapters that investigated how environmental stimuli of abiotic and biotic origin influence grapevine physiology and fruit chemistry. In the first chapter, data was collected on 23 weather- and plant-related variables at nine different Grüner Veltliner (Grüner V.; Vitis vinifera L.) vineyards within a large geographic region for three years to determine how these variables influenced the volatile and non-volatile phenolic composition of Grüner V. wines. The second chapter assessed pre-bloom early leaf removal (ELR) and how increasing carbon limitation related to increasing ELR severities affects Grüner V. production parameters, fruit maturity, and volatile composition. Grüner V. is new grapevine variety to wine producing regions of the eastern U.S., and little is known about optimal production practices for Grüner V. grape and wine production. The guiding objectives of these two studies were to address this knowledge gap by determining the main weather- and plant-related drivers of Grüner V. wine volatile and phenolic composition and identifying an optimal ELR severity for highly vegetative Grüner V. that balances improvements in fruit and juice quality with penalties on vine yield and viability. Chapters three and four evaluated the responses of grapevine resource allocation and physiology to repeated phloem-feeding by increasing population densities of SLF and if physiological responses vary at different scales (i.e., single-leaf vs. whole-plant) and in time. The third chapter targeted how single-leaf gas exchange and end-of-season allocation of carbon and nitrogen resources are affected by SLF. The fourth chapter assessed the responses of whole-vine hydraulic functioning and vascular dynamics, and if SLF phloem-feeding induces similar responses at the whole-vine scale as those measured at the single-leaf scale in the first SLF chapter. Since SLF is a novel invasive insect pest that already has dealt economically relevant damage to Pennsylvania grape and wine producers, the objectives of these chapters were to determine how SLF phloem-feeding affects fundamental aspects of grapevine functioning and if grapevine responses change due to adult SLF population densities. This knowledge can subsequently be used to assist with development of economic action thresholds for SLF management in vineyard systems. In the first chapter, a combination of weather- and plant-related variables explained a high degree of variation measured in the volatile composition of Grüner V. wines produced from different vineyards within a large region, while phenolic composition was explained to a lower degree. Despite the high degree of variation in volatile composition that was explained by weather- and plant-related variables, the overall vintage effect was a stronger influence on wine volatile composition than variation in these variables among vineyards, at least for the volatile compounds measured. The second chapter illustrated how ELR can be an effective tool for improving fruit quality and altering juice volatile composition in Grüner V., while highlighting how high ELR severities (i.e., 8-12 leaves shoot-1) can negatively impact vine yield across years. The third and fourth chapters show how medium-to-high SLF densities (8-15 SLF shoot-1) can reduce grapevine gas exchange and whole-vine hydraulic functioning, while altering resource allocation dynamics by reducing the concentrations of belowground carbon storage reserves and driving an accumulation of carbon in aboveground tissues instead. These chapters also identified tissue-specific effects of SLF phloem-feeding on xylem and phloem tissues, namely by identifying and visualizing SLF-inflicted feeding damage localized to the phloem tissues while detecting shifts in diurnal tissue radius dynamics that reflect reduced xylem water flow and likely altered phloem carbon dynamics. Overall, these four chapters highlight how environmental stimuli from abiotic and biotic origins can affect grapevine physiology and fruit chemistry.