애기나리와 큰애기나리에 발생하는 Cercospora dispori의 형태∙분자적 계통 분석 = Morphological and molecular phylogenetic analysis of Cercospora dispori from Disporum smilacinum and Disporum viridescens

다국어 초록 (Multilingual Abstract)

The genus Cercospora is one of the major fungal pathogens commonly associated with leaf spot disease on a wide range of plants worldwide, possessing considerable phytopathological significance. Cercospora species have also been found on plants of the genus Disporum. Among them, D. smilacinum and D. viridescens are primarily distributed in Southeast Asia, particularly in Korea. Notably, Cercospora infections on these two host plants have been reported only from Korea and Japan. The Cercospora species occurring on Disporum plants has been identified as C. dispori, which is known to exhibit host specificity to D. smilacinum and D. viridescens. This fungus shows host specificity on D. smilacinum and D. viridescens, identified as C. dispori. However, the previously reported data were incomplete, lacking either morphological or molecular information. Moreover, no type strain has been designated, and only a single CBS isolate has been reported, which limits the reliability of this species identification. Therefore, in this study, we compiled and re-evaluated the existing records of Cercospora dispori associated with D. smilacinum and D. viridescens to establish a standardized framework for the accurate characterization and identification of this species. Specimens were collected from more than three regions in Korea for each host species, D. smilacinum and D. viridescens, and the pathogens were isolated and identified. The morphological characteristics of stromata, conidiophores, conidia, and septa were examined in the morphological analysis. Phylogenetic analyses were conducted using five nuclear loci (ITS, actA, cmdA, his3, and tef1) with the maximum likelihood (ML) method implemented in RAxML-GUI 2.0.14, which based on the GAMMA model with the GTR substitution. The multilocus phylogenetic analysis revealed that the isolates obtained from D. smilacinum and D. viridescens formed a single well-supported clade, demonstrating their host specificity. This study emphasizes the necessity of analyzing multiple isolates for accurate pathogen diagnosis. And systematically demonstrates the importance of integrating morphological and molecular data for the reliable identification of plant pathogenic fungi, including C. dispori.

목차 (Table of Contents)

• Chapter 1. Literature review 1
• 1.1. Introduction to Cercospora and related genera 1
• 1.1.1. The genus Cercospora: general characteristics 1
• 1.1.2. Taxonomic history and species delimitation in Cercospora 4
• 1.1.3. Phylogenetic approaches and marker selection in Cercospora 7
• 1.1.4. Ecological roles and importance 9
• 1.2. Overview of the genus Disporum and its distribution in Korea 11
• 1.2.1. Taxonomy and diversity of Disporum 11
• 1.2.2. Disporum in Korea 12
• 1.2.3. Cercospora species associated with Disporum plants 13
• 1.3. References 14
• Chapter 2. Integrated morphological and molecular analysis of Cercospora dispori
• on Disporum smilacinum and D. viridescens 17
• 2.1. Introduction 17
• 2.2. Materials and methods 20
• 2.2.1. Sample collection 20
• 2.2.2. Morphological observation 20
• 2.2.3. Fungal isolation 22
• 2.2.4. DNA extraction, PCR amplification, and sequencing 22
• 2.2.5. Phylogenetic analysis 25
• 2.3. Results 26
• 2.3.1. Morphological and molecular phylogenetic analysis 26
• 2.3.2. Fungal classification 30
• 2.4. Discussion 34
• 2.4.1. Cercospora dispori in Korea 34
• 2.5. Conclusion 36
• 2.6. Reference 37
• 국문 초록 39