Physiological analysis and transcriptome profiling reveals the impact of microplastic on melon (Cucumis melo L.) seed germination and seedling growth

Zhiying Li; Xiaolei Zeng; Fenghang Sun; Taojie Feng; Yuxuan Xu; Zewei Li; Jinghua Wu; Gefu Wang-Pruski; Zhizhong Zhang

doi:10.1016/j.jplph.2023.154039

Physiological analysis and transcriptome profiling reveals the impact of microplastic on melon (Cucumis melo L.) seed germination and seedling growth

J Plant Physiol. 2023 Aug:287:154039. doi: 10.1016/j.jplph.2023.154039. Epub 2023 Jun 12.

Authors

Zhiying Li¹, Xiaolei Zeng¹, Fenghang Sun¹, Taojie Feng², Yuxuan Xu², Zewei Li¹, Jinghua Wu¹, Gefu Wang-Pruski³, Zhizhong Zhang⁴

Affiliations

¹ Joint FAFU-Dalhousie Lab, College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
² Joint FAFU-Dalhousie Lab, College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Fujian Yongan Vegetable Science and Technology Backyard, Sanming, 366000, China.
³ Joint FAFU-Dalhousie Lab, College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, B2N 5E3, Canada.
⁴ Joint FAFU-Dalhousie Lab, College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Fujian Yongan Vegetable Science and Technology Backyard, Sanming, 366000, China. Electronic address: Zhizhongzhang@fafu.edu.cn.

PMID: 37329743
DOI: 10.1016/j.jplph.2023.154039

Abstract

The wide application of agricultural plastics leads to microplastic (MP) accumulation in the soil and inevitably result in MP pollution. Melon is an economically important horticultural crop that is widely cultivated with plastic film mulching. However, the impact of MP pollution on plant growth remains largely unclear. Here we reported the morphological, physiological, biochemical responses and transcriptome re-programing of melon responses to MP on seed germination and seedling growth. Polyvinyl chloride particles were added to potting mix to simulate MP exposure environment (MEE). The results showed that low and medium concentrations (1-4 g kg^-1) of MEE had a significant adverse effect on seed germination and seedling growth. In both cases, the germination potential was decreased, young root forks increased, and tips decreased; and the dry weight of seedlings, the total length, surface area, forks and tips of root were also decreased. However, the root activity was increased. The concentration of MEE to give the best parameters was at 2 g kg^-1. Catalase enzymatic activity and reactive oxygen species (ROS) in roots were decreased continuously with increased MEE concentrations. The peak values of peroxidase activity, O₂^.- content and generation rate, ROS enrichment and malondialdehyde content all reached the highest at 2 g kg^-1. MEE also increased the proline content and decreased the contents of ascorbic acid, soluble sugar and soluble protein in these seedlings. Medium and high concentrations of MEE (4-8 g kg^-1) also increased the chlorophyll b content. Low concentrations MEE (1-2 g kg^-1) inhibited actual photochemical efficiency of photosystem II and photochemical quenching, two key chlorophyll fluorescence parameters. Transcriptome analysis showed that the differentially expressed genes caused by the MEE were mainly belonged to defense response, signal transduction, hormone metabolism, plant-pathogen interaction, and phenylpropanoid biosynthesis. The results of this study will help to understand the ecotoxicological effects of MEE on melons and provide data for ecological risk assessment of Cucurbitaceae vegetable cultivation.

Keywords: Chlorophyll a fluorescence; Melon; Microplastic exposure; Osmoregulation substances; Reactive oxygen species.

MeSH terms

Cucumis melo* / genetics
Cucumis melo* / metabolism
Cucurbitaceae* / metabolism
Gene Expression Profiling
Germination
Microplastics / metabolism
Microplastics / pharmacology
Plastics / metabolism
Plastics / pharmacology
Reactive Oxygen Species / metabolism
Seedlings / metabolism
Seeds

Substances

Microplastics
Plastics
Reactive Oxygen Species