Analysis of the energy source at the early stage of poplar seed germination: verification of Perl's pathway.

Adenosine triphosphate (ATP) is produced at the early stage of seed germination and provides the energy for metabolism. The source of ATP in seeds may be Perl's pathway, but this has not yet been confirmed. In this study, using germinating seeds of poplar as the experimental materials, the transcript levels of genes related to Perl's pathway were determined by real-time PCR. The activities of enzymes in Perl's pathway were also determined. The results were verified by comparison with RNA-Seq and metabolomics data. The results showed that there were high transcript levels of some genes encoding malate dehydrogenase (MDH), phosphoenolpyruvate carboxykinase (PEPCK), pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH), and pyruvate kinase (PK) at the early stage of germination (0.75 h). The enzymes MDH, PEPCK, PK, PDC, and ADH showed peaks in activity at around 0.75 h and 6 h during germination. The oxaloacetate concentration was high in poplar seeds at the early stage of germination. This study provides experimental data showing that Perl's pathway participates in supplying energy during the early stages of poplar seed germination, and lays the foundation for further studies on the complex metabolic processes that function during seed germination.