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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Research Project #437846

Research Project: Resilient, Sustainable Production Strategies for Low-Input Environments

Location: Crops Pathology and Genetics Research

Project Number: 2032-21220-008-000-D
Project Type: In-House Appropriated

Start Date: Mar 18, 2020
End Date: Mar 17, 2025

Objective 1: Develop crop production strategies that integrate water and nutrient input management and the environment for healthy, sustainable vineyards. [NP 305, Component 1, Problem Statement 1B] • Subobjective 1.A. Characterize varied responses of grapevine genotypes to drought in order to improve detection and interpretation of water stress signals for local and remote proximal sensors and to develop precision irrigation techniques tailored to genotype- specific root responses. • Subobjective 1.B. Determine the molecular basis associated with the differential responses to drought stress among grapevine genotypes. • Subobjective 1.C. Identifying threshholds for organoleptic volatile phenols and their glycosidically-bound derivatives in wine grape varieties exposed to smoke taint across different growing regions. Expected benefits include standardized chemical analyses of smoke taint compounds in exposed and unexposed vineyards for the wine varietals growing in CA, OR, and WA with the goal of identifying and quantifying genotype-specific environmental threshold levels. Objective 2: Analyze the interaction of soil health and vineyard floor management for the enhancement of vine and fruit quality. [NP 305, Component 1, Problem Statement 1B] • Subobjective 2.A. Determine relationships among soil and grape must microbiomes and their structure in the wine grape production system. Objective 3: Develop improved strategies for controlling grapevine disease using preventative and post-infection management strategies. [NP 305, Component 1, Problem Statement 1B] • Subobjective 3.A. Characterize the role of wood-decay fungi in trunk diseases, to develop post-infection practices that return vines to productivity. • Subobjective 3.B. Identify when trunk pathogens sporulate and the infection courts by which they infect, to develop preventative practices that protect susceptible host tissues.

The approaches for each objective range from experimentation under controlled conditions in the greenhouse to experimentation under natural field conditions, with commercial vineyards making up the majority of field study sites. Prior to hypothesis testing, some level of methods development (e.g., imaging water flowing through the vessels of living plants, pathogen detection from environmental samples of microscopic spores) is required for each objective, in part because grape is not a model study system. For objective 1, parallel sets of physiological experiments are focused on measuring anatomical, physiological, and transcriptional responses of leaves and fine roots, under normal levels of irrigation versus under drought stress. Whole plants of Vitis vinifera wine-grape varieties (Cabernet-Sauvignon, Chardonnay) and rootstocks with differential drought tolerance will be examined by X-ray microCT, followed by sections of leaves and roots examined by transmittance electron microscopy and Laser Capture Microdissection. RNA-seq techniques will then be used to seek out transcriptional differences at a molecular scale. For Sub-Objective 1.C.-The approach will combine field experimentation in the vineyard, winemaking and distilling processes in the experimental winery, and laboratory analyses of smoke-related compounds using, for e.g., gas chromatography/mass spectrometry (GC/MS). Compositional changes in the fruit of different cultivars, with exposure to smoke, will be characterized and quantified. Smoke-related compounds in wines made from the smoke-exposed fruit will also be characterized and quantified. Grape and wine quality analytical methods will be developed to detect key smoke-related compounds in the fruit and the wine, and acceptable limits will be established. Further, endproduct processing methods will be developed to help mitigate such compounds. For objective 2, the interaction of host genotype by environment (soil and climate, specifically) by management is examined. High-throughput amplicon sequencing of soil fungi and bacterial communities will be used to compare those of vine rows under different floor-management practices. Samples from the must will evaluate whether vineyard floor management practices impact the microbiome during fermentation. Diffuse reflectance Fourier transformed mid-infrared spectroscopy (DRIFTS) will be used to characterize changes in SOM chemical composition in particulate organic matter and other soil C fractions. For objective 3, inoculations of potted plants in the greenhouse will be used to test hypotheses at the plant scale about which combinations of pathogens and sequences of infection cause disease symptoms, and also about how differential tissue susceptibility affects whether an infection spreads throughout an individual plant. At the vineyard scale, spore trapping in diseased vineyards and evaluations of pruning-wound susceptibility will be used to determine when grapevines are at greatest risk of infection.