Changes in growth competence of aged Trichoderma viride vegetative mycelia

Abstract

Identical masses of submerged Trichoderma viride mycelia of various ages were used as inoculum for a second submerged cultivation lasting for 24 h. It was found that the growth yield of secondary culture was dependent on the age of inoculum. The growth yields increased when the age of primary culture was less than 3 d, and decreased down to zero when older mycelia were inoculated. The mycelia were living even after 1 month of submerged cultivation, as they formed conidia after inoculating onto solid medium. In order to elucidate underlying biochemical processes, developmental changes of specific activities of organellar marker enzymes were measured in the mitochondrial/vacuolar and microsomal fractions of mycelia. These activities changed during the growth of mycelia in a biphasic manner and their time courses were remarkably similar. Only the H(+)-ATPase activity decreased monophasically with the age of mycelia. Membrane-bound proteases of both membrane fractions changed differently upon ageing. These results could not be explained as a consequence of nutrient starvation and indicate that the prolonged submerged cultivation triggers coordinated series of biochemical events which leads to the loss of growth competence.

Isolation spore production and Kochs postulates of <i>Elsinoe pyri</i>

“…The culture morphology of E. pyri on PDA also changed as the culture aged, with sectoring occurring when the cultures were 2 months old. Aging of ascomycetes has been studied in many species and is known to cause changes in growth or death of cultures (Schwartz & Osiewacz 1996;Osiewacz 2002;Simkovic et al 2007). However, reduced conidial viability after sub-culturing may be less common, particularly when large numbers of apparently non-viable conidia are produced.…”

Changes in metabolome and in enzyme activities during germination ofTrichoderma atrovirideconidia

“…Activities of marker enzymes were measured according to methods described previously in Šimkovič et al . (). Citrate synthase was measured by the spectrophotometric method using Ellman's reagent (Shepherd & Garland, ).…”