Detection, characterization, and phytotoxic activity of the nucleoside antibiotics, Blasticidin S and 5-Hydroxylmethyl-Blasticidin S

Screening for herbicidal compounds carried out on culture broths of Streptomyces strains isolated from soil resulted in the detection of potent phytotoxic activity. The active principles were isolated, and identified as the nucleoside antibiotics Blasticidin S (Bl-S) and 5-Hydroxymethyl-Blasticidin S (H-M-Bl-S). Bl-S was more active than H-M-Bl-S on seedling germination in petri dishes and in postemergence greenhouse tests. Moreover both antibiotics were more phytotoxic to dicotyledonous than to monocotyledonous plants. The increased sensitivity of dicots was confirmed in carrot and rice cell cultures. Both compounds also inhibited [14C]amino acid incorporation into proteins of rice and carrot cell cultures. Protein synthesis was more affected in carrot than rice.