Vince Rivas
Program: Master’s Program in Ecology
Date: Tuesday, July 28, 2026
Time: 11:00am
Location: Donald P. Shiley BioScience Center (BSCI)
Zoom: https://SDSU.zoom.us/j/87141139360
Committee Members
Dr. David Lipson
Dr. Lluvia Flores-Renteria
Dr. Amy Quandt
Abstract
Coast live oak (Quercus agrifolia) is a keystone species in California, supporting lifecycles and biotic interactions for thousands of species and providing environmental services, such as carbon sequestration, erosion control, and the promotion of groundwater infiltration.
In recent years, nonviable, black acorns have been observed in Q. agrifolia populations in parts of San Diego County; however, these abnormal acorns have not been described in literature, indicating the potential presence of a new disease. The goals of this study are: 1. determine the spatial distribution of symptomatic, black acorns throughout San Diego County, 2. describe and compare the microbial community assemblage between acorns in symptomatic and asymptomatic trees, and 3) determine if pathogens from acorns can be transmitted to seedlings through soil. In order to achieve objective 1, twelve sites throughout the County were assessed for the presence of symptomatic acorns in Q. agrifolia trees. For objective 2, black acorns were collected from various sites for DNA extractions and PCR using specific primers to target conserved regions: internal transcribed spacer (ITS) for fungi and 16S rRNA for bacteria. For objective 3, acorn germinants were inoculated with symptomatic and asymptomatic acorn samples and were grown to check for pathogen presence. As novel disease outbreaks are predicted to increase with climate change, this research hopes to reveal if a new disease has infected the coast live oak.