Alginate oligosaccharide induces resistance against Penicillium expansum in pears by priming defense responses

Solairaj Dhanasekaran; Lisha Liang; Yaqi Chen; Jingwei Chen; Shuaiying Guo; Xiaoyun Zhang; Lina Zhao; Hongyin Zhang

doi:10.1016/j.plaphy.2025.109531

Alginate oligosaccharide induces resistance against Penicillium expansum in pears by priming defense responses

Plant Physiol Biochem. 2025 Jan 21:220:109531. doi: 10.1016/j.plaphy.2025.109531. Online ahead of print.

Authors

Solairaj Dhanasekaran¹, Lisha Liang¹, Yaqi Chen¹, Jingwei Chen¹, Shuaiying Guo¹, Xiaoyun Zhang¹, Lina Zhao², Hongyin Zhang³

Affiliations

¹ School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China.
² School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China. Electronic address: linabobo0706@163.com.
³ School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China. Electronic address: zhanghongyin126@126.com.

PMID: 39862456
DOI: 10.1016/j.plaphy.2025.109531

Abstract

The research intended to explore the control ability of alginate oligosaccharide (AOS) on Penicillium expansum infection in pear fruit by priming response and its mechanism. The results showed that 100 mg L^-1 AOS treatment could significantly reduce the incidence of postharvest blue mold and the lesion diameter in pear fruits and maintain their quality. The defense responses induced by AOS treatment alone were relatively mild in pear fruits. Still, AOS-treated pear fruits inoculated with P. expansum showed more intense disease resistance responses. These defense responses included enhanced activities of chitinase (CHI), β-1, 3-glucanase (GLU), peroxidase (POD), polyphenol oxidase (PPO), phenylalanine ammonia-lyase activity (PAL), along with the accumulation of total phenolic compounds, flavonoids and lignin. Additionally, the expression levels of defense-related genes, such as PbGLU, PbCHI, PbPAL, PbPOD and PbPPO, were significantly upregulated. However, AOS did not show a potential inhibitory effect on the in vitro growth of P. expansum. Our results indicated that AOS treatment in the postharvest pear fruit enhances disease resistance by priming its defense responses.

Keywords: Alginate oligosaccharide; Defense response; Induced resistance; Pear; Penicillium expansum.