Postharvest Physiological Deterioration in Cassava Roots

Postharvest physiological deterioration (PPD) in cassava storage roots is a rapid and multifaceted stress response triggered by mechanical injury at harvest. Within hours, an oxidative burst generates reactive oxygen species (ROS) that activate calcium-mediated signalling cascades and the synthesis of secondary metabolites. Among these, coumarins such as scopoletin accumulate at wound sites and, upon oxidation, produce the characteristic blue-black vascular streaking. Enzymatic browning and cell-death processes spread from the harvest wound throughout the root, rendering tubers unpalatable within 24–72 hours. The severity and rate of PPD are influenced by genetic background, environmental factors, dry matter content and the capacity of antioxidant enzyme systems. Economically, PPD constrains marketability and exacerbates food losses across tropical regions where cassava is a staple. Research efforts span breeding for tolerant cultivars, genome-editing of key biosynthetic genes, optimisation of harvest and storage protocols, and the development of rapid diagnostic methods. Integration of molecular, biochemical and sensor-based approaches is now advancing our understanding of regulatory networks and enabling practical solutions to extend shelf-life in farm-to-market supply chains.

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Postharvest Physiological Deterioration in Cassava Roots publication trend

The graph below shows the total number of articles in postharvest physiological deterioration in cassava roots across all publications each year (not limited to Nature Index journals).

Technical terms

Postharvest physiological deterioration (PPD): The rapid onset of spoilage symptoms in cassava roots after harvest, marked by discolouration, tissue collapse and loss of quality.

Reactive oxygen species (ROS): Highly reactive molecules, including hydrogen peroxide, produced in response to wounding that can trigger oxidative damage and signalling pathways.

Scopoletin: A coumarin derivative that accumulates in wounded cassava roots and, upon oxidation, contributes to the blue-black discolouration characteristic of PPD.

Dry matter content (DMC): The proportion of solid constituents in the root (starch, fibre and proteins), which influences PPD resistance and processing quality.

RNA interference (RNAi): A biological mechanism for sequence-specific gene silencing, used experimentally to reduce expression of target genes and assess their roles in PPD.

p-Coumaroyl shikimate/quinate 3′-hydroxylase (C3′H): An enzyme catalysing a key step in the biosynthesis of coumarins, whose activity has been directly linked to PPD symptom development.

References

1. A method for rapid and homogenous initiation of post-harvest physiological deterioration in cassava storage roots identifies Indonesian cultivars with improved shelf-life performance. Plant Methods (2023).
2. Reactive oxygen species turnover, phenolics metabolism, and some key gene expressions modulate postharvest physiological deterioration in cassava tubers. Frontiers in Microbiology (2023).
3. Cassava postharvest physiological deterioration: a complex phenomenon involving calcium signaling, reactive oxygen species and programmed cell death. Acta Physiologiae Plantarum (2017).
4. Knockdown of p-Coumaroyl Shikimate/Quinate 3′-Hydroxylase Delays the Occurrence of Post-Harvest Physiological Deterioration in Cassava Storage Roots. International Journal of Molecular Sciences (2022).