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A Simple and Effective Technique for Production of Pycnidia and Pycnidiospores by Macrophomina phaseolina
Xinbei Zhao1, Yunxia Ni1, Xintao Liu1
1Institute of Plant Protection, Henan Academy of Agricultural Sciences, Key Laboratory of Integrated Pest Management on Crops in Southern Region of North China, Ministry of Agriculture, Henan Key Laboratory of Crops Pest Control, Zhengzhou, Henan, China 450002.
Abstract:
Production of pycnidia and pycnidiospores by Macrophomina phaseolina is not often seen in vitro. The objective of this study is to develop a simple and effective technique to obtain pycnidiospores of M. phaseolina isolates in vitro and to evaluate germination rates and pathogenicity of pycnidiospores. We found M. phaseolina isolates can produce pycnidia on oatmeal agar (OMA) under ultraviolet light with 365 nm wavelength (UV). For evaluating the effect of OMA and UV on growth of M. phaseolina, combinations of two agar media and three lighting conditions were tested. The results confirm that all six M. phaseolina isolates produced pycnidia only on OMA under UV. The pycnidiospores produced on OMA under UV had germination rates higher than 90%. In pathogenicity tests, inoculation with the pycnidiospores showed symptoms later than inoculation with hypha-colonized toothpicks. Significant differences in the pathogenicity is detected between isolates Mp2014003 and Mp2014024 when inoculation is done with the pycnidiospores (P < 0.001), but not when hypha-colonized toothpicks are used as inoculum (P = 0.091). This study provides a new method for obtaining pycnidiospores of M. phaseolina for future investigations.
Insights
A new method using oatmeal agar and UV light effectively produces pycnidiospores from Macrophomina phaseolina (M. phaseolina) in vitro. These pycnidiospores show high germination and pathogenicity, aiding future research on this plant pathogen.
Area of Science:
- Plant Pathology
- Mycology
- Microbial Culture Techniques
Background:
- Macrophomina phaseolina (M. phaseolina) pycnidia and pycnidiospore production is rarely observed in laboratory settings.
- Effective in vitro methods are needed for studying M. phaseolina pycnidiospores.
Purpose of the Study:
- To develop a simple and effective in vitro technique for producing M. phaseolina pycnidiospores.
- To evaluate the germination rates and pathogenicity of M. phaseolina pycnidiospores.
Main Methods:
- Tested combinations of two agar media and three lighting conditions, including oatmeal agar (OMA) and ultraviolet (UV) light (365 nm wavelength).
- Evaluated pycnidiospore germination rates.
- Conducted pathogenicity tests comparing pycnidiospore inoculation with hypha-colonized toothpick inoculation.
Main Results:
- All six M. phaseolina isolates produced pycnidia exclusively on OMA under UV light.
- Pycnidiospores produced via this method exhibited germination rates exceeding 90%.
- Pycnidiospore inoculation resulted in delayed symptom development compared to hypha-colonized toothpicks, with significant pathogenicity differences observed between isolates (P < 0.001).
Conclusions:
- Oatmeal agar combined with UV light provides an effective method for in vitro pycnidiospore production of M. phaseolina.
- The developed method yields viable pycnidiospores suitable for germination and pathogenicity studies.
- This technique facilitates future research on M. phaseolina, particularly concerning its pycnidiospore stage.
