Integrated physiological, transcriptomic and metabolomic analyses reveal potential mechanisms of potato tuber dormancy release.

Abstract

Regulating potato tuber dormancy is crucial for crop productivity and food security. We conducted the first comprehensive physiological, transcriptomic, and metabolomic investigations of two varieties of long and short dormant potato tubers in order to clarify the mechanisms of dormancy release. In the current study, three different dormant stages of UGT (ungerminated tubers), MGT (minimally germinated tubers), and GT (germinated tubers) were obtained by treatment with the germination promoter gibberellin A₃ and the germination inhibitor chlorpropham. The results revealed that the contents of reducing reducing sugar, sucrase, glutamine synthetase, and nitrate reductase were increased in the dormancy release stages, whereas the contents of sucrose and starch were decreased, leading to a change in the phenotype of the potato tuber bud eyes. According to transcriptomic and metabolomic investigations, four metabolomic pathways were impacted by the dormancy release process. Zeatin biosynthesis was identified in both potato varieties in the dormant release stage (trans-zeatin riboside, isopentenyl adenosine, 5'-methylthioadenosine, IPT, CYP735A, CKX, and UGT73C); glutathione metabolism was identified in short-dormant potato varieties ((5-L-Glutamyl)-L-amino acid, oxidized glutathione, GPX, IDH1, GGT1_5, and GST); and the pentose phosphate pathway (D-Xylulose 5-phosphate, ribose 1-phosphate, PGD, and RPIA) and the phenylpropanoid biosynthesis (caffeic acid, sinapine, CYP98A, and CSE) were identified in long-dormant potato varieties. In conclusion, the four pathways mentioned above involve DEGs and DEMs that are crucial to the control of tuber dormancy release. This work offers a theoretical foundation and useful recommendations for potato tuber quality improvement and molecular breeding.