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ARS Home » Pacific West Area » Pullman, Washington » Grain Legume Genetics Physiology Research » Research » Publications at this Location » Publication #410211
Research Project: Enhancing Agronomic Performance and Nutritional Qualities of Pulse Crops

Location: Grain Legume Genetics Physiology Research

Title: Biological Control of Clubroot of Rapeseed (Plasmodiophora brassicae) by the Endophytic Fungus Didymella macrostoma P2

Author
item CHENG, JUNYU - Huazhong Agricultural University
item LUO, TAO - Huazhong Agricultural University
item WU, MINGDE - Huazhong Agricultural University
item ZHANG, JING - Huazhong Agricultural University
item YANG, LONG - Huazhong Agricultural University
item Chen, Weidong
item LI, GUOQING - Huazhong Agricultural University

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2024
Publication Date: 7/22/2024
Citation: Cheng, J., Luo, T., Wu, M., Zhang, J., Yang, L., Chen, W., Li, G. 2024. Biological Control of Clubroot of Rapeseed (Plasmodiophora brassicae) by the Endophytic Fungus Didymella macrostoma P2. Plant Disease. 108(8):2399-2409. https://doi.org/10.1094/PDIS-09-23-1921-RE.
DOI: https://doi.org/10.1094/PDIS-09-23-1921-RE

Interpretive Summary: Plant diseases are major constraints of crop and vegetable production. Management of plant diseases is challenging. Certain diseases are extremely hard to control, such as clubroot disease caused by Plasmodiophora brassicae, due to its wide host range, longevity in soil and fungicide resistance. in the pathogen population. An effective biological agent is needed to control clubroot disease. This study investigated the fungus Didymella macrostoma P2 as a biocontrol agent. It was found that D. macrostoma P2 produces several strong antimicrobial compounds and can suppress the pathogen P. brassicae and control clubroot disease. More importantly, D. macrostoma P2 can grow endophytically and be applied as seed treatments that allow it to establish inside plants. Its endophytic growth induces plant resistance to clubroot disease. The induced resistance is also effective against a number of other diseases. This research demonstrates that D. macrostoma P2 can be exploited as an effective biocontrol agent for a number of diseases.

Technical Abstract: Didymella macrostoma P2 was isolated from rapeseed (Brassica napus). It displayed weak virulence on rapeseed, but showed strong antagonism against various pathogens of rapeseed, suggesting that P2 can be exploited to control rapeseed diseases such as clubroot caused by Plasmodiophora brassicae. To test this hypothesis, this study was carried out to detect production of antimicrobials by P2 and to determine efficacy of the antimicrobials and pycnidiospores of P2 in suppression of P. brassicae. Results showed that the cultural filtrates (CF) of P2 in potato dextrose broth and the substances in pycnidiospore mucilages exuded from the P2 pycnidia had an inhibitory activity against P. brassicae. In the indoor experiment, seeds of the susceptible rapeseed cultivar Zhongshuang 9 treated with P2 CF and the pycnidiospore suspension of P2 (P2 SS, 1 × 107 spores/mL) reduced clubroot severity by 31–70% on the 30-day-old seedlings compared to the control (seeds treated with water). In the field experiment, seeds of another susceptible rapeseed cultivar Huayouza 50 treated with P2 CF, P2 CE (chloroform extract, 30 µg/mL) and P2 SS reduced clubroot severity by 29–48% on 60-day-old seedlings and by 28–59% on adult plants (220 days) compared to the control treatment. The three P2 treatments produced significantly (P < 0.05) greater seed yield than the control treatment, and had seed yields similar to that produced by the resistant rapeseed cultivar Shengguang 165R in one of the two seasons. These results suggest that D. macrostoma P2 is an effective biocontrol agent against rapeseed clubroot.