In vitro interaction between Castanea spp. tissue cultures and Cryphonectria parasitica crude extracts

Crude extracts (CEs) of a virulent strain (V-E4) of Cryphonectria parasitica significantly reduced calli fresh weight in both susceptible Castanea sativa and resistant C. mollissima when used at 50 and 500 g g-1 and, in general, showed an inhibitory effect on either O2 uptake and H+-ATPase activity. On the contrary, CEs of a hypovirulent strain (H-E13) induced a slight, but significant early increase on callus growth of both genotypes and the enhancement of the physiological activities. Chemical investigations carried out on the CEs of both H-E13 and V-E4 showed noticeable differences in the production of secondary metabolites. The three compounds isolated from H-E13 CEs and completely characterised by spectral analysis and derivatization reactions are: L-p-hydroxyphenyllactic acid, diaporthin and a new compound, called cryphonectric acid.