FaPKc2.2 negatively modulates strawberry fruit ripening by reprograming the carbon metabolic pathway

Abstract

Although the main contribution of pyruvate kinases in the energy providing and regulation of plant growth or seed development have been discovered, the potential roles of these enzymes in the fruit ripening process has not been well elucidated so far. In this study, a total of 53 pyruvate kinases (PKs) were identified in the genome of octoploid strawberry. Expression specificity in the fruit led to the identification of a cytosolic PK (FxaC_15g00080, namely FaPKc2.2), which was inhibited by both ABA and sucrose, either alone or synergistically. It was expressed in both vegetative and reproductive organs. Subcellular localization analysis confirmed that the FaPKc2.2 was a cytosolic PK. Transient overexpression of the FaPKc2.2 obviously inhibited the ripening of strawberry fruits. Biochemical and transcriptomic data further revealed that the upregulation of the FaPKc2.2 systematically reprogrammed metabolisms, mainly by channeling the main flux from carbon to amino-acid related nitrogen biomolecules. These results demonstrated the regulatory role of the FaPKc2.2 in the fruit ripening and highlighted the probability of utilizing the gene in strawberry fruit quality improvements.