Location: Crop Improvement and Genetics Research
Project Number: 2030-21220-003-023-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2025
End Date: Aug 31, 2026
Objective:
The following research objectives will be pursued:
Objective 1: Expand early time-course expression profiling to better capture the dynamics of transcriptional responses to smoke.
Objective 2: Extend expression analysis to additional glycosyl transferase gene families.
Objective 3: Optimize the grapevine genome browser to support CRISPR guideRNA design and gene editing efforts.
Objective 4: Perform CRISPR-Cas editing of selected smoke-induced gene candidates in Chardonnay.
Approach:
The overall goal of the project is to investigate the molecular responses of grape berries to wildfire smoke, focusing on factors that contribute to smoke taint. The grapevine fruit transcriptome will be examined at multiple new time points (3, 6 and 12 hours) following a controlled smoke-exposure event. Also, the expression analysis and detailed protein annotation will be performed on a wider array of potential glycosyl transferase genes to broaden the scope of the evaluation to include more genes which may be associated with the biosynthesis of more stable diglycosides and may function downstream of other glycosyl transferases. The expression profiling will include the later timepoints of 24 and 48 hour post exposure to help determine whether they contribute to the conversion of monoglycosylated volatile phenols into more stable forms. Additional bioinformatic tools will be developed to support gene editing guide RNA design capabilities to design of CRISPR-Cas9 guides that are conserved across multiple cultivars. Single nucleotide polymorphisms and insertion deletion data from Chardonnay, Merlot, and Syrah will be integrated into the existing Cabernet Sauvignon genome browser in www.grapegenomics.com.
Prior research identified 12 glycosyl transferases named Vitis vinifera smoke-inducible UGTs (VviSIUGTs) that were significantly upregulated in response to smoke exposure. Nine of these VviSIUGTs were consistently upregulated in two independent experiments of smoke exposed fruit. Their expression peaked one day post-exposure and declined by day three, mirroring glycoside accumulation dynamics. Gene co-expression network analyses highlighted stress-responsive modules enriched in these VviSIUGTs, while transcription factor binding site analyses pinpointed stress-related regulatory elements in their promoters. Gene editing constructs will be designed and constructed for these gene targets and submitted to the UC Davis Plant Transformation Facility for grapevine transformation.