Project properties

Title Metabolic and molecular description of sugar pathway in post-harvested onions (Allium cepa L.)
Group Plant Breeding, Laboratory of
Project type thesis
Credits 24-39
Supervisor(s) Antonino Crucitti, Olga Scholten
Examiner(s) Christian Bachem, Olga Scholten
Contact info A Crucitti (antonino.crucitti@wur.nl)
Begin date 2021/09/01
End date 2022/02/28
Description Onion is one of the most valuable horticultural crops worldwide. Onion is a biennial species that forms a bulb during the first year, which serves as overwintering structure. The shoot apical meristem of the bulb remains dormant for a while and gives rise to sprout formation and flowers in the second year.

Early breaking of dormancy is a major issue in onion shelf life and storability. Prolonging onion dormancy depends on many factors such as pre- and post-harvest specific environmental conditions, with a considerable effect of the genotype.

Genetic regulation of dormancy in onion is basically unknown. However, as described in other plant species, it is known that sugar pathway has a considerable role in the re-activation of the shoot apical meristem and therefore, in the formation and elongation of the sprout.

Fructans are the main reserve carbohydrates in onion bulbs. They are soluble sugars stored in the cells during the bulbing phase, allowing the bulb to survive during winter. Fructans are thought to be transported to the lower part of the bulb prior that sprouting happens (Ohanenye et al., 2019), and then depolymerized into simple sugars, mainly fructose, to fuel the growth of the sprout. Nonetheless, it is unclear how this process is organised and regulated at a molecular level.

Overall, the aims of this thesis project are: 1) to investigate fructans and other carbohydrate quantity and quality in different tissue samples collected in 2020/2021 storage season; 2) to identify candidate genes linked to sugar metabolism and mobilization; 3) to perform a gene expression analysis of the candidate genes potentially involved in carbohydrate pathway in post-harvested onions.
Used skills Metabolite profiling, gene expression analysis, statistical analysis.
Requirements BSc in plant science or equivalent