Nutrient leakage from dried and rewetted conidia of Alternaria brassicae and its effect on the mycoparasite Nectria inventa
Conidia of Alternaria brassicae leaked various amino acids and sugars when they were exposed to an alternate dry–wet condition; the longer the drying period, the larger the amount of leakage. Among the amino acids, glutamine was exuded in the largest amount, followed by aspartic acid and glutamic acid. The sugar fraction consisted mainly of glucose and fructose. These leaked nutrients stimulated germination and growth of the mycoparasite of A. brassicae, Nectria inventa. As a result, the germination rate of Alternaria conidia was drastically reduced to less than 5% and they were eventually destroyed by N. inventa. In the absence of N. inventa, however, conidia of A. brassicae germinated at the rate of 93.7% after being dried for 12 h at 32% RH.