|ISLAM, MD SAJEDUL - Foreign Agricultural Service (FAS, USDA)|
|CABRERA-LA ROSA, JUAN - Non ARS Employee|
|CIVEROLO, EDWIN - Retired ARS Employee|
|GROVES, RUSSELL - University Of Wisconsin|
Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/19/2015
Publication Date: 6/1/2015
Citation: Lin, H., Islam, M., Cabrera-La Rosa, J.C., Civerolo, E.L., Groves, R.L. 2015. Population structure of Xylella fastidiosa associated with almond leaf scorch disease in the San Joaquin Valley of California. Phytopathology. 105(6):825-832.
Interpretive Summary: Xylella fastidiosa (Xf) causes almond leaf scorch (ALS) disease. However, genetic diversity and population structure of Xf associated with ALS are not clear. In this study, a DNA molecular marker system was used to assess population genetics of ALS Xf in the San Joaquin Valley of California. Results show that genetic forms of ALS Xf are tightly associated with almond cultivars regardless of locations, suggesting host selection is a major driving factor shaping ALS Xf populations. This finding provides new information for understanding ALS epidemiology in the San Joaquin Valley of California.
Technical Abstract: Xylella fastidiosa (Xf) causes disease in many commercial crops including almond leaf scorch (ALS) disease in susceptible almond (Prunus dulcis). In this study, genetic diversity and population structure of Xf associated with ALS disease were evaluated. Strains isolated from two almond production sites in the San Joaquin Valley of California were analyzed with simple sequence repeat (SSR) markers. The distribution of genotypes, combined with UPGMA and STRUCTURE analyses, revealed two major genetic clusters that were associated with cultivars, ‘Sonora’ and ‘Nonpareil’, regardless of the year of study or location. These relationships suggest that host selection and adaptation are major driving forces shaping ALS Xf population structure in the San Joaquin Valley. This finding may provide insight into understanding pathogen adaptation and host selection in the context of ALS disease dynamics.