Monorden from a novel source, Neocosmospora tenuicristata: Stereochemistry and plant growth regulatory properties.

Abstract

When Neocosmospora tenuicristata was cultured on shredded wheat medium, monorden was produced in relatively large quantities. Monorden significantly (p<0.01) inhibited the growth of etiolated wheat coleoptiles at 10-3 and 10-4 M, by 100 and 44% respectively, relative to controls. Neither 6-week-old tobacco plants nor 10-day-old bean plants were affected by monorden sprays, but 10-day-old corn plants had slight necrosis when treated with 10-2 M solutions. Bacillus subtilis and B. cereus were moderately inhibited by monorden. Single crystal X-ray diffraction studies defined the entire stereochemistry for the first time and the three asymmetric carbon atoms had R configurations. Thus, the configuration of the CH3 at C17 has now been established.