The epiphytic microbiota of sour rot-affected grapes differs minimally from that of healthy grapes, indicating causal organisms are already present on healthy berries

• Published in: PloS one Vol. 14; no. 3; p. e0211378
• Main Authors: Hall, Megan E, O'Bryon, Isabelle, Wilcox, Wayne F, Osier, Michael V, Cadle-Davidson, Lance
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 27-03-2019; Public Library of Science (PLoS)
• Subjects: Abundance; Acetic Acid; Acetic acid bacteria; Acetobacter - pathogenicity; Agriculture; Bacteria; Berries; Bioinformatics; Biology; Biology and Life Sciences; Candida; Cultivars; Deoxyribonucleic acid; DNA; Drosophila; Earth Sciences; Ecology and Environmental Sciences; EDTA; Ethanol; Etiology; Experiments; Fermentation; Fruit - microbiology; Fruit flies; Fruit flies (Tephritidae); Grapes; Hanseniaspora; Harvest; High-throughput screening (Biochemical assaying); Host Microbial Interactions - physiology; Insects; Laboratories; Life sciences; Microbiomes; Microbiota; Microbiota (Symbiotic organisms); Microbiota - physiology; Next-generation sequencing; Organic acids; Organisms; Physical Sciences; Pichia; Plant Diseases - etiology; Plant Diseases - microbiology; Plant pathology; Plant sciences; Research and Analysis Methods; Saccharomyces; Signs and symptoms; Sour rot; Species; Vineyards; Vitaceae; Vitis - microbiology; Wine - microbiology; Wineries; Yeast; Yeasts - pathogenicity; Modesto California; New York; United States > US; Missouri; Tasmania Australia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0211378

Sour rot is a disease complex produced by an interaction between grape berries and various species of yeast and acetic acid bacteria in the presence of Drosophila fruit flies. While yeast and bacteria are consistently found on healthy grape berries worldwide, we explored whether the composition of these epiphytic communities differed depending on the presence or absence of sour rot symptoms. Using high-throughput sequencing, we characterized the microbiome of sour rot-affected grapes from two geographical areas across two years. In 2015 and 2016, both healthy and sour rot-affected berries were collected from commercial and research vineyards in Geneva, NY and commercial vineyards in Tasmania, AUS. In this experiment, all associated organisms grouped together primarily by location, and not by presence/absence of symptoms or cultivar. The predominant difference between asymptomatic and symptomatic samples, regardless of location, was the abundance of Acetobacter species, which were significantly more plentiful in the symptomatic samples. Yeast genera such as Candida, Hanseniaspora, Pichia and Saccharomyces were abundant in both sets of samples, but varied by region. The consistent presence of yeast species and the increased abundance of acetic acid-generating bacteria is consistent with our understanding of their etiological role in sour rot development. In 2016, diseased grapes also were collected from vineyards in Fredonia, NY, and Modesto, CA. Consistent with our comparison study, all associated organisms again grouped together primarily by location. Yeast genera such as Candida, Hanseniaspora, Pichia and Saccharomyces were abundant in both sets of samples, but varied by region. The consistent presence of yeast species and the abundance of acetic acid-generating bacteria in both experiments is consistent with our understanding of their etiological role in sour rot development.