Polyphenol oxidase genes as integral part of the evolutionary history of domesticated tetraploid wheat

Francesca Taranto 
IBBR - UOS Portici (NA) - Italy

March 17, 2021 (11:30-12:30)
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Abstract: Enzymatic browning is a colour reaction occurring in plants, including cereals, due to oxidation during postharvest processing and storage. This has a negative impact on the colour, flavour, nutritional properties and shelf life of food products. Browning is usually caused by polyphenol oxidases (PPOs), following cell damage caused by senescence, wounding and the attack of pests and pathogens. Several studies indicated that PPOs play a role in plant immunity, and emerging evidence suggested that PPOs might also be involved in other physiological processes. PPOs are copper containing enzymes that are nearly ubiquitous among plants. Studying and understanding the genetic basis of PPO-related traits plays a crucial role for the genetic improvement of crops. A tetraploid wheat collection (T. turgidum ssp., TWC), including durum wheat cultivars, wild and domesticated accessions, was genotyped using the 90K wheat SNP iSelect assay and phenotyped for PPO activity during three growing seasons. The polymorphic SNPs were used to perform genome-wide association analysis (GWA) in TWC and durum wheat sub-groups (DWC). Then, the marker-trait associations (MTAs) were used to predict candidate genes responsible for PPO activity. Based on the MTAs detected in TWC, two haplotypes associated with low and high PPO activity were identified. The GWA results reveal PPO genes as integral part of the evolutionary history of domesticated tetraploid wheat. Indeed, the MTAs were useful to provide new information important to understanding the domestication process of T. turgidum ssp. and in particular of ssp. carthlicum. In this study, it emerged a different origin of the carthlicum subspecies and its potential in starting new breeding programs as a unexplored sources. Our work add new information about the breeding process of durum wheat and on the causes that favored the fixation of PPO alleles for low PPO activity in modern varieties. Finally, the GWA analysis was useful to develop new functional markers that could be used in the future marker-assisted selection breeding programs for PPO activity

Author's Info: https://ibbr.cnr.it/ibbr/info/people/francesca-taranto