ASHS 2024 Conference

Preservation of nutritional and market qualities of potato tubers during postharvest storage is essential for optimum economic return. Protecting tubers from unintended sprouting during storage is one of the major postharvest challenges that potato growers and stakeholders encounter. Storage environment, particularly storage temperature, significantly impacts dormancy progression and sprouting and effect overall marketability. Potato tubers carry significant amount of microbiome in different tissues of tubers from field to storage, which might contribute to overall storage qualities. However, how storage temperature impacts overall potato tuber microbiome and how changes in microbiome influence tuber dormancy are largely unknown. Therefore, the primary objective of this study was to investigate the impact of different storage temperatures on tuber microbiome and monitor the dormancy progression and sprout growth during long-term storage. Certified seed tubers of Russet Burbank were cured after harvest following industry practices. Then, one subset of tubers was stored at constant 8°C, and a second subset was stored at constant 21°C. Three types of tuber tissues (primary meristem, secondary meristem, and tuber flesh) were collected after 4, 8, 12, 17, and 24 weeks of storage for microbiome profiling and sugar and protein analysis. Additionally, a third subset was generated by moving tubers from 8°C to 21°C three days before sampling time of 8, 12, and 17 weeks. Tuber dormancy progression was monitored using additional subsets for each storage condition. As expected, the subset of tubers stored at 8°C had delayed sprouting compare to 21°C, and rapid sprout growth was observed when tubers were moved from 8°C to 21°C. Increase in reducing sugar content was observed in meristem tissues, while it decreased in tuber flesh with progression of storage duration. Interestingly, higher protein content was determined in secondary meristem tissues compare to primary meristems and tuber flesh. Overall, greater bacterial and fungal diversity and abundance were observed in meristem tissues when compared to tuber flesh. Additionally, storage temperatures, storage time, and tuber tissue types significantly impacted tuber microbial profile. In tuber tissues, Ascomycota and Basidiomycota were predominant fungal phyla, while Actinobacteria, Proteobacteria, and Cyanobacteria were the predominant bacterial phyla. Our results suggested that storage temperature and storage duration significantly impact both dormancy progression and tuber microbiome and subsequently contribute to postharvest qualities of potato tubers.