Tolerance mechanism of pear to hypoxic storage: A transcriptome study

Abstract

Postharvest pear (Pyrus communis L.) is often stored at low temperatures under an atmosphere with low O₂ and high CO₂ partial pressure (‘controlled atmosphere storage’, CA). While this condition helps to maintain fruit quality and prolong storage life, how the long-term hypoxia impacts the pear transcriptome is unknown. This study aimed to explore changes in the pear transcriptome associated with CA storage using RNA-sequencing. ‘Conference’ pears were stored for 6 months at either CA or regular air. Over 270 million paired-end reads were mapped onto the Pyrus communis ‘Bartlett’ DH Genome and differences between the expression profiles of CA-stored and regular air-stored fruits were assessed. Genes involved in energy status, redox state, secondary metabolism, and lipid biosynthesis were highly altered in hypoxic pears. Additionally, differentially expressed genes (DEG) related to cell senescence, apoptosis, autophagy, and plant hormone signaling were detected. This study is the first to highlight the potential involvement of crucial programmed cell death (PCD) factors, including vacuolar processing enzyme, metacaspase, and substilase, in CA-stored pear fruit. By integrating the pathways of these DEGs into a conceptual model, a coping mechanism for ‘Conference’ pear to long-term hypoxic-CA storage is proposed. These new markers might help to reveal the molecular causes of storage disorders triggered by low O₂ conditions.