Effect of Factors on Conidium Germination of Botrytis cinerea in vitro

Botrytis cinerea is a necrotrophic fungal plant pathogen distributed worldwide. The early stages of epidemiology namely spore germination is a topic of great interest among researchers. In the current study, the effect of various physical, chemical and nutritional factors on germination of B. cinerea conidia were studied in vitro. Results showed that there was no particular influence of spore age (5-14 days) on germination in 10 mM fructose. In addition, germination-self-inhibition was found to be associated with increased spore concentrations (above 4.5×105 conidia/ml) without significant differences between fungal isolates. When setting different pH values in the medium, conidial germination of B. cinerea was impaired by pH values below 6 and above 8. However, germination of B. cinerea was strongly enhanced (>90% after 24 hours) in the presence of sugars (i.e. fructose, sucrose and glucose) at concentrations above 100 mM, whilst the cations (Ca2+, Mg2+, K+, and Fe2+ ) had no visible influence on conidial germination at a wide range of concentrations (0.001-1mM). With other additives and in the presence of inorganic nitrogen forms (i.e. NH4 and NO3), conidial germination responded similarly with no particular influence on germination, whilst germ tube growth and elongation increased progressively with increasing concentrations of both N-forms.