Effects of the Polyamine Biosynthesis Inhibitor Difluoromethylornithine on Growth, Polyamine Levels, Chromosome Behaviour and Polygenic Traits in Wheat ( Triticum aestivum L.)

Abstract

Specific inhibition of fungal polyamine (PA) biosynthesis by DL-α-difluoromethylornithine (DFMO, an inhibitor of ornithine decarboxylase) has proved to be a novel and promising approach for the control of several fungal plant infections. However, the effects of application of DFMO on the physiology and cytogenetics of the host plant has not been studied in depth. We accordingly undertook these experiments on wheat ( Triticum aestivum L. cv. Agra local) which show that up to 5 mM DFMO had no significant effect on growth, chlorophyll content, cellular PA levels, chromosome behaviour, pollen fertility and polygenic traits of wheat plants; in fact, it caused a significant increase in growth, chlorophyll content, PA levels and yield in some of the treatments. However, the highest concentration of DFMO (10 mM) reduced seedling growth and PA levels, and occasionally induced some chromosomal alterations such as unoriented chromosomes at metaphase and anaphase in root cells. Further, other PA inhibitors, methylglyoxal bis (guanylhydrazone) (MGBG) and cyclohexylamine (CHA) even at 10 mM did not affect the seedling growth, except DL-α-difluoromethylarginine (DFMA—5 and 10 mM) which induced significant reduction in growth of the seedlings. These observations suggest that DFMO could be safely used as a protectant against fungal plant diseases without affecting the host plant, since many fungal infections reported so far are controllable by 1 mM DFMO or lower concentrations.