Trehalose metabolism coordinates transcriptional regulatory control and metabolic requirements to trigger the onset of cassava storage root initiation

Cassava storage roots (SR) are an important source of food energy and raw material for a wide range
of applications. Understanding SR initiation and the associated regulation is critical to boosting
tuber yield in cassava. Decades of transcriptome studies have identified key regulators relevant to
SR formation, transcriptional regulation and sugar metabolism. However, there remain uncertainties
over the roles of the regulators in modulating the onset of SR development owing to the limitation of
the widely applied differential gene expression analysis. Here, we aimed to investigate the regulation
underlying the transition from fibrous (FR) to SR based on Dynamic Network Biomarker (DNB)
analysis. Gene expression analysis during cassava root initiation showed the transition period to
SR happened in FR during 8 weeks after planting (FR8). Ninety-nine DNB genes associated with SR
initiation and development were identified. Interestingly, the role of trehalose metabolism, especially
trehalase1 (TRE1), in modulating metabolites abundance and coordinating regulatory signaling and
carbon substrate availability via the connection of transcriptional regulation and sugar metabolism
was highlighted. The results agree with the associated DNB characters of TRE1 reported in other
transcriptome studies of cassava SR initiation and Attre1 loss of function in literature. The findings
help fill the knowledge gap regarding the regulation underlying cassava SR initiation.