Optimization of Culture Conditions for Mycelial Growth and Sporulation of Myrothecium roridum

Muhammad Iqbal,Sumera Naz,Saira Mehboob,Hafiz M Riaz,Ghulam Mohy-Ud-Din,Shumaila Farooq,Salik N Khan,Muhammad Idrees

doi:10.33687/phytopath.010.01.3415

Abstract

Culture and nutrition conditions of Myrothecium roridum Tode were optimized by conducting a series of interlined experiments on a growth medium, temperature, pH, and photoperiod. In contrast, relation of culture age with virulence was measured by fungal development on young leaves of bitter gourd. The physiological response was measured on colony radial growth and spore production. Among the six test growth media, i.e., nutrient agar (NA), potato dextrose agar (PDA), Czapek-Dox agar (CDA), glucose agar (GA), malt extract agar (MEA), and bitter gourd agar (BGA), the highest radial growth (77 mm) and the highest number of spores (239 × 106 spores/ml) were observed on PDA. Incubation temperature was evaluated between a range of 15-40 °C, and the highest colony growth (87 mm) was observed at 30 °C, whereas the highest spore production (315 × 106 spores/ml) was at 35 °C. Different pH levels, i.e., 5, 5.5, 6, 6.5, 7, and 7.5, were optimized, and the highest colony growth (87 mm) and spore production (504 × 106 spores/ml) was recorded at pH 5.0. Impact of photoperiod was studied, and the highest mycelial growth (88 mm) and maximum spore production (524 × 106 spores/ml) was observed at 16/8 h alternate light and dark period. It was concluded that the optimum conditions for mycelia growth and spore production was pH 5.0-6.0 and at 30 ± 2 °C in PDA with 16/8 h alternate light and dark photoperiod.

Highlights

Myrothecium roridum is a facultative parasite with a large number of plant hosts, including vegetables, fruits, and ornamental plants (Murakami and Shirata, 2005; Silva and Meyer, 2006)
The role of temperature seemed to be more dominant towards the radial growth and spore production
Compatibility of virulence attribute of plant pathogenic fungi with growth medium and incubating conditions are essential for conducting investigations on disease management strategies

Summary

Introduction

Myrothecium roridum is a facultative parasite with a large number (around 263 plant species) of plant hosts, including vegetables, fruits, and ornamental plants (Murakami and Shirata, 2005; Silva and Meyer, 2006) It is widely distributed in the world's hot and humid tropical climates and has been recognized as a serious damaging agent to the leaf, crown, and fruit of the plant. In Pakistan, the Myrothecium leaf spot (MLS) disease of bitter gourd was first reported in 1988 at Faisalabad district of Punjab province (Ali et al, 1988). Later on, it was found associated with seeds and isolated frequently from rotted and un-germinated seeds of cucurbits during seed health testing (Shakir and Mirza, 1992; Sultana and Ghaffar, 2007). In the present investigation, different nutrition and cultural conditions were employed to find optimum conditions to harvest virulent cultures of the fungus so that reliable investigations for onward studies on disease management

Methods

Results

Conclusion