Comparative transcriptome analysis provides insights into ABA alleviating postharvest physiological deterioration of cassava

Abstract

Cassava, a staple crop in tropical regions, suffers from rapid postharvest physiological deterioration (PPD), limiting its shelf life. Although abscisic acid (ABA) has shown potential in alleviating PPD, the underlying regulatory pathways remain largely unexplored. In this study, physiological assays demonstrated that exogenous ABA alleviated PPD in cassava by decreasing H₂O₂ content. Temporal-resolution transcriptome analyses identified gene expression changes in cassava tuberous roots during PPD, with 1,338, 2,718, and 5543 genes differentially expressed after 6, 12, and 48 h of treatment, respectively. GO enrichment analysis revealed that ABA-induced DEGs exhibited functions such as response to oxygen radical, lignin metabolic process, and positive regulation of signal transduction. Co-expression network analysis identified three significant gene modules comprising 167 transcription factors (TFs) from 28 families, with 17 TFs predicted to regulate six key antioxidant enzyme genes through corresponding promoter motifs. The upregulated expression of these genes was subsequently validated by quantitative real-time PCR (qRT-PCR). Furthermore, yeast one-hybrid (Y1H) and dual-luciferase assays provided direct evidences that MeMYB114 and MeHAT22 regulate the expression of MePOD10, while MeERF110, MeWRKY057, and MeHAT22 were shown to activate MePOD18 expression. These findings indicate that MeMYB114/MeHAT22/MeERF110/MeWRKY057-MePOD pathway is a crucial component involved in ABA-regulated PPD alleviation in cassava.