Abstract
Orobanche minor is an obligate root parasitic weed belonging to Orobanchaceae. Some root parasitic weeds of Orobanchaceae cause serious damage to many agronomically important crops worldwide. A novel and effective strategy for the parasitic weed control is desired for economical and humanitarian reasons. Since the life cycle of parasitic weeds is significantly different from that of host plants, understanding of the parasite-specific biological events is important for design of selective control strategies. We focused on the germination process of parasitic weeds to find biological events specific to these species and conducted metabolic profiling of O. minor seeds. Consequently, we revealed that gentianose was decreased immediately after GR24 treatment. Gentianose is a trisaccharide consisted of two glucoses and a fructose. An inhibitor of glycosyl hydrolases, nojirimycin bisulfite (NJ), decreased the germination rate. From these results, we hypothesize that gentianose metabolism is essential for germination of O. minor seed and the key enzyme in the gentianose metabolic pathway could be a novel target for selective control of parasitic weeds. In this study, we extracted crude enzymes from O. minor seeds and measured glycosyl hydrolyzing activity. We revealed that the enzyme involved in germination did not exist in the soluble fraction, but associated with the insoluble components, most likely the cell wall.
