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Mail : leticia.meza@inrae.fr

Sujet de thèse

Leveraging Grapevine Plant-Microbe Interactions to Optimize Agricultural Strategies

• Co-Supervision : Pascal Lecomte, Jessica Vallance, Patrice Rey (UMR SAVE), Philippe Rolshausen (University of California at Riverside, USA)
• Fundingt : GTDfree project (HENNESSY 2020 extension)
• Ecole doctorale : University of California, Riverside (USA)
• Période à SAVE : Octobre 2019 - Juin 2020

Résumé

Grapevine (Vitis vinifera L.) has been cultivated for thousands of years for commercial value for their delicious fresh fruit, dried fruit, juice and wine production, with France and the United States now being two of the largest producers and exporters. However, a major impediment to grape production are the impacts caused by Grapevine Truck Diseases (GTD), of which ESCA is one of the most cosmopolitan and destructive. Often variable and covert symptom development make observation and monitoring a difficult task for both young and mature vineyards, small or large. Unfortunately, to date there are no curative methods or treatments for GTD. Consequently, preventive strategies, including vineyard cultural management such as consideration for training and pruning methods may be essential for control. This is because, although GTD inoculum can infect grapevines through any open wound, pruning wounds are the main gateway for fungal spores. There are many types of training systems and pruning practices. Within this, Leticia’s research interests are driven by the following questions:

• 1) What is the influence of cultural practices on the incidence and severity of GTD?
• 2) What is the composition and function of plant-associated microbes in grapevine biocompartments and their impact on GTD outcomes?

Therefore, it is the objective of this thesis to look at ESCA and the impact of pruning wounds as it affects disease incidence and severity.

The first research theme illustrates the main theme of the laboratory at the University of California Riverside in the Rolshausen lab, which is specialized in the study of the microbiome of several crops of interest in California (vine, citrus, and other fruits). Within this research theme she aims to characterize the epiphytic and endophytic microbiome on pruning wounds of grapevines in conventional and organic vineyards. The second research theme integrates into action 1 of GTDfree: "Influence of environmental factors (farming practices, climate) on the development of wood diseases". The second theme within her thesis will be developed by exploiting a new molecular detection technique, digital droplet PCR,  and to combine different sub-studies (survey to identify pairs of plots, observations, evaluation of the impact of esca, rate of internal necrosis , classical and molecular detection and identification (qPCR) of the pathogens present. Together her thesis aims to contribute to the understanding of the diversity and composition of microbial communities in GTDs. In particular fungal communities in vine wood as it is impacted by different pruning practices, as it may lead to improved management strategies and identification of novel biofertilizers and biological control agents.

Expérience professionnelle

• Graduate Student Rotations

Fall 2016 - Summer 2017
University of California, Riverside, Labs: Patricia Springer, Sean Cutler and Carolyn Rasmussen  

• Research Assistant

Fall 2015 - Spring 2016
The Field Museum of Natural History, Advisor: Dr. Noé De La Sancha
Topic title: “Developing microsatelites for Akodon montensis in eastern Paraguay”  

• Research Assistant

Summer 2013 – Spring 2016
Chicago State University, Advisor: Dr. Christopher Botanga
Topic Title: Evaluation of Cell Wall Biosynthetic Genes in Hollow and Solid Stemmed Genotypes in Wheat,” and “Genetic Evaluation the Basis of the Occurrence of Tall Off-types in the Semi-dwarf Spring Wheat”

• Amgen Scholar

Summer 2015
University of California at Berkeley, Molecular and Cell Biology Department, Advisor: Abby Dernburg
Topic Title: “NIPP it: A Characterization of Nuclear Inhibitor of Protein Phosphatase Type-1 During Meiosis in C. elegeans”

Formation

• PhD Candidate

Year: Current
University of California, Riverside, California, USA
Major: Botany and Plant Sciences

• Bachelors in Biological Sciences

Year: May 2016
Chicago State University, Chicago, Illinois, USA
Major: Biology