# Physiological and Metabolic Mechanisms of Penicillium sclerotigenum-Induced Postharvest Rot in Lichuan Yam (Dioscorea polystachya Turcz.)

## TL;DR

This study identifies how the fungus Penicillium sclerotigenum causes rot in Lichuan yams by disrupting water and nutrient balance and altering metabolic pathways.

## Contribution

The study reveals the physiological and metabolic mechanisms by which Penicillium sclerotigenum induces postharvest rot in Lichuan yams.

## Key findings

- Penicillium sclerotigenum disrupts water-retaining structures, increasing weight loss and reducing water activity in yams.
- The infection alters carbon-nitrogen metabolism, affecting starch, sugar, and protein levels in the host.
- Metabolomics showed changes in sugars, organic acids, and secondary metabolites, with enriched sugar and amino acid pathways.

## Abstract

Postharvest decay results in substantial losses during yam storage. This study isolated microorganisms from decayed Lichuan yams and investigated deterioration mechanisms using physiological assays and UPLC-MS/MS. Among six isolates, Penicillium sclerotigenum was identified as the primary pathogen. Infection disrupted water-retaining structures, leading to increased weight loss and reduced water activity. It also disrupted carbon-nitrogen metabolism, leading to fluctuations in starch, sugar, and protein content. Although host defense responses were activated via phenolic accumulation and the upregulation of peroxidase (POD) and polyphenol oxidase (PPO) activities, sustained infection resulted in severe membrane lipid peroxidation. Metabolomics revealed alterations in sugars, organic acids, and secondary metabolites, with the specific enrichment of sugar and amino acid pathways. Thus, P. sclerotigenum remodels yam energy metabolism and defense responses. This study clarifies the physiological and metabolic mechanisms underlying this fungal rot, providing a theoretical foundation for the development of preventive control strategies.