Understanding low oxygen stress in apple fruit during postharvest storage

ISHS Secretariat
Understanding low oxygen stress in apple fruit during postharvest storage

The modern consumer has become accustomed to a year-round supply of apple fruit. This continuous availability is possible through long-term storage techniques. Growers are able to extend fruit quality by controlling the immediate atmosphere around the apple, combining a low oxygen and high carbon dioxide gas mixture with low temperatures. This form of long-term storage is referred to as controlled atmosphere (CA) storage. In some cases, the storage conditions are too severe for the fruit and result in storage disorders. This is caused by the low oxygen environment, but details surrounding the stress regulation on a genetic level and how it results in or helps to prevent the storage disorders, still remain unclear. Studies conducted on model organisms, including Arabidopsis thaliana and Oryza sativa, showed that low oxygen stress in plants is regulated by the group VII ethylene response factor (ERF-VII) gene family. The family consists of five genes responsible for sensing low oxygen levels in the plant environment, particularly during flooding, and subsequently triggering the required survival response. Because limited information is available on this stress response pathway in fruits, this project aimed to elucidate stress regulation in apple fruit during CA storage, particularly at the genetic level. The project expanded on traditional postharvest techniques by incorporating biotechnology approaches, including phylogenetic analysis to identify apple gene homologs for the ERF-VII gene family. The next step was to functionally characterize the identified genes. Both in vitro protein characterization and ectopic studies in over-expressing A. thaliana reporter lines were conducted to further elucidate the gene function during CA storage. Due to the practical limitations of working with apple trees to obtain over-expressing apple fruit, it was decided to study gene activity in vivo, by creating over-expressing apple callus reporter lines. By incorporating these biotechnology-based techniques, we aim to better understand the stress fruit experience as a result of the low oxygen atmosphere, ultimately preventing the development of internal disorders during CA storage.

Suzane Pols won the ISHS Young Minds Award for the best oral presentation at the XIII International Controlled and Modified Atmosphere Research Conference (CAMA2021), which was held virtually in Belgium in August 2021.

Suzane Pols, MeBioS division, KU Leuven, Willem de Croylaan 42, 3001 Heverlee, Belgium, e-mail: suzane.pols@kuleuven.be

The article is available in Chronica Horticulturae

postharvest storage
Young Minds Award Winners