Calcium effect on the mycelial cell walls of Botrytis cinerea

The goal of this study was to determine whether calcium ion, (one of the electrolytes released after plant cell attack), may have a direct effect on fungal growth and chemistry of the fungal cell wall. B. cinerea was grown on Richard's solution containing different amounts of CaCl 2, and the cell walls were extracted from the mycelium after 7 days of growth. Mineral, neutral and aminosugar, protein and uronic acid contents were determined. At 1 g l −1 CaCl 2, only the aminosugar content increased. At 2 g l −1 CaCl 2, neutral sugar synthesis was reduced, whereas the uronic acid content increased. For higher CaCl 2 concentrations, the calcium ion content of the cell wall increased, resulting in reduced protein and neutral sugar contents. Meanwhile, the cell wall proportion of the mycelia increased on a dry weight basis due to an increase in uronic acid, Ca, P, Na and neutral sugar contents of the cell wall with increasing CaCl 2 in the media. The resulting thickening of the fungal cell wall caused by calcium ion may be an important factor in the host-pathogen relationship.