EFFECT OF POLYAMINES AND THEIR BIOSYNTHETIC INHIBITORS ON THE GROWTH OF HELMINTHOSPORIUM TURCICUM

Effect of polyamines and their biosynthetic inhibitors on the growth of Helminthosporium turcicum was studied. Putrescine (0.01 to 0.5 mM) spermidine (0.01 to 1.0 mM) and spermine (0.01 to 0.5 mM) promoted the mycelial growth of fungus as compared to control when added to Czapek medium. Higher concentrations of these polyaminies proved lethal for growth of the fungus. Both DFMO and DFMA inhibited the mycelial growth strongly at the concentration of 5.0 mM. The inhibitory effect of DFMA was more pronounced than DFMO. Combined effect of DFMO and DFMA on the mycelial growth at 1.0 mM each was more pronounced than DFMO alone at 1.0 mM concentration. The combined effect was still lesser than DFMA alone at 1.0 mM concentration. In reversal experiments, addition of 0.1 and 0.5 mM putrescine with 1.0 and 5.0 mM DFMO respectively, improved the mycelial growth. Addition of 0.5 and 1.0 mM putrescine with 1.0 mM and 5.0 mM DFMA respectively, reversed the inhibitory effect of DFMA on the mycelial growth.