Establishment of a detached leaf pathogenicity assay for pepper anthracnose = 고추 탄저병 병원성 평가를 위한 잎 검정법 확립

다국어 초록 (Multilingual Abstract)

Pepper anthracnose, caused by Colletotrichum scovillei, is one of the most destructive diseases threatening pepper production in Korea. Detached pepper fruits are commonly used for pathogenicity assays; however, obtaining fruits through plant cultivation requires substantial time and labor. Although commercial fruits can serve as alternatives, essential meta-information—such as cultivar, post-harvest storage duration, and potential chemical residues—is typically unavailable, often resulting in non-reproducible pathogenicity assay outcomes. To address this limitation, we examined pathogenicity assays under various conditions in pepper seedlings and detached leaves. As a result, we developed a detached leaf pathogenicity assay that offers applicability and consistency comparable to the fruit assay. Using 3-week-old pepper seedlings, we evaluated the effects of conidial suspension concentration, temperature, and incubation period on the pathogenicity of C. scovillei. When inoculated with a 10⁶ spores/mL conidial suspension and incubated at 25 °C for 7 days, the detached leaf assay did not differ statistically from the fruit assay under optimal conditions. We further assessed its feasibility for fungicide efficacy testing by examining the effects of fungicide concentration and spray timing on control efficacy. Taken together, these results support the detached leaf assay as an efficient and reproducible alternative to the fruit assay for evaluating the pathogenicity of C. scovillei.

국문 초록 (Abstract)

고추 탄저병은 Colletotrichum scovillei에 의해 발생하며 국내 고추 생산에 큰 피해를 주는 주요 병해이다. 병원성 검정에는 고추 열매를 이용한 검정법이 널리 사용되고 있으나, 실험용 열매를 확보하기 위해서는 재배에 많은 시간과 노동력이 필요하다. 시중에서 판매하는 고추 열매를 대체재로 사용할 수 있으나 품종, 저장 기간, 잔류 농약과 같은 핵심 정보가 제공되지 않아 실험 결과의 재현성이 떨어지는 한계가 있다. 본 연구에서는 이러한 문제를 보완하기 위해 잎과 유묘를 대상으로 다양한 조건에서 병원성 검정을 수행하였으며, 잎을 이용한 병원성 검정법을 개발하였다. 3주령 고추 유묘를 이용하여 분생포자 농도, 온도, 배양 기간이 병원성 발현에 미치는 영향을 평가하였으며, 106 spores/mL 접종, 25°C 배양, 접종 후 7일 평가 조건에서 잎 검정법은 열매 검정법과 통계적으로 유의한 차이를 보이지 않았다. 또한 살균제 농도와 처리 시기에 따른 방제 효과를 비교하여 본 검정법의 적용 가능성을 확인하였다. 이러한 결과는 잎을 이용한 병원성 검정법이 C. scovillei의 병원성 및 살균제의 방제 효과를 평가하는 데 있어 효율적이고 재현성 높은 대안적 방법임을 제시한다.

목차 (Table of Contents)

• ABSTRACT i
• CONTENTS iii
• LIST OF TABLES v
• LIST OF FIGURES vi
• INTRODUCTION 1
• MATERIALS AND METHODS 4
• 1. Growth of pepper seedlings 4
• 2. Preparation of pepper fruits 4
• 3. Preparation of conidial suspension and inoculation 4
• 3.1 A seedling assay 5
• 3.2 A leaf and a fruit assay 5
• 4. Factors affecting the pathogenicity of C. scovillei on seedlings 6
• 5. Factors affecting the pathogenicity of C. scovillei on leaves 6
• 6. Evaluation of the control efficacy of fungicides 7
• 7. Data analysis 8
• RESULTS 9
• 1. Anthracnose development under various environmental conditions in seedlings and detached leaves 9
• 2. Comparison of the leaf pathogenicity assay and fruit pathogenicity assay under optimal conditions 17
• 3. Effects of fungicide concentration and spray timing on control efficacy 20
• DISCUSSION 24
• 1. Establishment of a standardized detached leaf pathogenicity assay for pepper anthracnose 24
• 2. Limitations of the leaf pathogenicity assay and the way forward 25
• LITERATURE CITED 27
• ABSTRACT IN KOREAN 29