Work

Mechanistic investigation of WRKY65-mediated defense responses to Penicillium expansum infection in pears

Year: 2026

Type: article

Abstract: Penicillium expansum is the predominant pathogen causing postharvest blue mold in pear fruit, leading to substantial economic losses and quality deterioration during storage. Although WRKY transcription factors are established regulators of plant immunity, the role of PbWRKY65 in pear resistance to P. expansum remains unclear. This study utilized Agrobacterium tumefaciens-mediated transient overexpression of PbWRKY65 in pear fruit to investigate its function in postharvest disease resistance. Compared to the empty-vector control, PbWRKY65 overexpression significantly reduced disease incidence and lesion diameter following P. expansum inoculation. Furthermore, PbWRKY65 overexpression markedly enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL), catalase (CAT), and ascorbate peroxidase (APX), while significantly decreasing lipoxygenase (LOX) activity and malondialdehyde (MDA) accumulation. Consistently, transcript levels of PbSOD , PbPOD , PbPPO , PbPAL , PbCAT , and PbAPX were significantly upregulated, whereas PbLOX expression was downregulated, indicating that PbWRKY65 strengthens both enzymatic and transcriptional defense responses. Transcriptome analysis further revealed extensive transcriptional reprogramming induced by PbWRKY65 overexpression, with differentially expressed genes enriched in metabolic processes, catalytic and antioxidant activity, and stimulus response. KEGG enrichment identified significant involvement of defense-related pathways, including flavonoid biosynthesis, phenylalanine metabolism, terpenoid backbone biosynthesis, carbon metabolism, and MAPK signaling. Collectively, these results demonstrate that PbWRKY65 positively regulates pear fruit resistance to P. expansum by enhancing antioxidant capacity, activating defense-related metabolic and signaling pathways, and alleviating oxidative damage. These findings suggest that PbWRKY65 may contribute to the resistance of pear fruit to P. expansum and provide a potential target for further investigation of disease resistance mechanisms and genetic improvement in pear.

Source: Postharvest Biology and Technology

DOI: 10.1016/j.postharvbio.2026.114771