Epicoccum sorghinum as leaf spot disease-causing pathogen in ginger (Zingiber officinale Rosc.) in China
Introduction
Ginger (Zingiber officinale Rosc.) is a perennial herbaceous plant belonging to the Zingiberaceae family (Zhang et al., 2019), and is also an edible and medicinal plant with high nutritional benefits (Wu et al., 2019). The rhizome of ginger is often used as culinary spice, as it displays distinctive aroma and flavor (Si et al., 2018). In addition, the substance extracted from ginger with anti-inflammatory, antibacterial, and anticancer properties have widely used as a Chinese herbal medicine (Grzanna et al., 2005; Habib et al., 2008; Singh et al., 2008). China is the largest producer and exporter of ginger in the world, with 29.45 million ha planted in 2021 (Wu et al., 2019; Wang et al., 2022a), furthermore, the yield of ginger in Shandong Province holds the top position with an annual output of 4 million tons, accounting for 45% of the total output of China (Ren and Li, 2021). However, with the continuous expansion of planting area, the obstacles of continuous cropping also appear and make ginger production threatened by many harmful organisms, such as fungi, nematodes, and bacteria (Rai et al., 2018; Hajhassani et al., 2019; Gao et al., 2021).
In recent years, the ginger industry has suffered huge losses due to the occurrence of multiple soil-borne diseases, including ginger bark cracking disease caused by root knot nematodes (Meloidogyne spp.), rot disease caused by fungi (Fusarium spp., Ceratocystis fimbriata, and Rhizopus oryzae) and diseases caused by bacteria (Pectobacterium brasiliense and Enterobacter cloacae) (Wang et al., 2021, 2022b; Liang et al., 2022; Zhang et al., 2020a; Gao et al., 2023; Zhao et al., 2022). In addition, foliar diseases are also important in ginger, affecting photosynthesis and reducing the quality and yield of ginger (Gao et al., 2021; Ruchi and Dohroo, 2005). Previous studies suggested that Nigrospora oryzae, Alternaria alternata, Phoma zingiberi, and Pantoea ananatis are virulent to ginger plants, causing foliar disease symptoms (Hu et al., 2022; Liu, 2009; Liu et al., 2022; Gao et al., 2021). In September 2020, leaf spot symptoms were observed on ginger leaves grown in planting fields near Laixi City, Shandong Province. The incidence of leaf spot ranged from 35% to 55%. Therefore, it was necessary to identify the pathogen of ginger leaf spot in this area for development of effective management measures.
The original objective of this study was to accurately determine the pathogens causing leaf spot of ginger using morphological observation, phylogenetic analysis, and pathogenicity test.
Section snippets
Sample collection and fungal isolation
To determine the pathogen causing ginger leaf spot in the fields, and we collected ginger leaves with typical symptoms. The early symptoms were small spots that gradually developed into circular or irregular necrotic lesions surrounded by chlorotic halos (Fig. 1A–C). In severe infection, large necrotic spots enlarged and coalesced, causing the leaves to wither and curl (Fig. 1A). Ten planting fields were randomly selected, and five diseased plants at the four corners and the center of the field
Morphological identification of the pathogen
A total of 62 pathogenic fungi were isolated from 50 naturally-infected leaves. These fungal isolates had highly similar colony morphology. Representative isolate Jiang-2-1 was selected for subsequent morphological observation, phylogenetic analysis, and pathogenicity determination. Colony was white to gray, round, with entire margins and luxuriant aerial hyphae, while the reverse side of the colony gradually turns reddish brown from the center to the periphery due to the accumulation of
Discussion
Epicoccum species have been reported as pathogens of many plant diseases. They can infect the roots, leaves, and fruits of plants, among which foliar diseases are the most frequently reported plant diseases (Taguiam et al., 2021). In recent years, many studies have reported that E. sorghinum is a pathogenic fungus causing many diseases. Liu et al. (2015) reported for the first time that E. sorghinum was responsible for sugarcane leaf spot disease. Moreover, E. sorghinum was also virulent to the
CRediT authorship contribution statement
Xiaoyan Yu: Formal analysis, Writing – review & editing. Zhihua Li: Acquired experiments. Rui Han: Visualization. Weiqian Zhang: Supervision. Jing Zhang: Methodology. Weiyue Cao: Software. Yue Ma: Investigation. Xiangjing Wang: Writing – review & editing. Junwei Zhao: Conceptualization, Validation, Data curation, Writing – review & editing. Wensheng Xiang: Conceptualization, Supervision, Validation, Data curation, Writing – review & editing.
Declaration of competing interest
We hereby declare that all authors of this manuscript have no known interests or personal relationship that could influence the reported work in this manuscript.
Acknowledgements
This research was financially supported by grants from the Key Program of the National Natural Science Foundation of China (No. 32030090), the Outstanding Youth Project of Natural Science Foundation of Heilongjiang Province (YQ2021C012), the Academic Backbone Project of Northeast Agricultural University (20XG33) and the Heilongjiang Postdoctoral Fund (LBH-Z17015).
References (44)
- et al.
Highlights of the Didymellaceae: a polyphasic approach to characterise Phoma and related pleosporalean genera
Stud. Mycol.
(2010) - et al.
Ginger extract (Zingiber offificinale) has anti-cancer and anti-inflflammatory effects on ethionine-induced hepatoma rats
Clinics
(2008) - et al.
Two divergent intragenomic rDNA ITS2 types within a monophyletic lineage of the fungus Fusarium are nonorthologous
Mol. Phylogenet. Evol.
(1997) - et al.
Taxonomy and phylogeny of Gliocladium analysed from nuclear large subunit ribosomal DNA sequences
Mycol. Res.
(1994) - et al.
Antioxidant activities of ginger extract and its constituents toward lipids
Food Chem.
(2018) - et al.
Chemistry, antioxidant and antimicrobial investigations on essential oil and oleoresins of Zingiber offificinale
Food Chem. Toxicol.
(2008) - et al.
Biocontrol potential of Bacillus altitudinis AMCC1040 against root-knot nematode disease of ginger and its impact on rhizosphere microbial community
Biol. Control
(2021) - et al.
Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics
- et al.
Analysis of world ginger production layout and trade pattern
North. Hortic.
(2019) - et al.
First report of Epicoccum sorghinum causing leaf spot on tea in China
Plant Dis.
(2019)