Exogenous amino acids inhibit seed germination and tubercle formation by Orobanche ramosa (Broomrape): Potential application for management of parasitic weeds

• Published in: Biological control Vol. 36; no. 2; pp. 258 - 265
• Main Authors: Vurro, Maurizio, Boari, Angela, Pilgeram, Alice L., Sands, David C.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.02.2006
• Subjects: Amino acid excretion; Amino acids; Biological control of weeds; essential amino acids; exogenous sources; Frenching disease; Fusarium oxysporum; inhibitors; Lycopersicon esculentum; Methionine; Mycoherbicides; Natural compounds; Orobanche; Orobanche ramosa; Parasitic plant management; parasitic plants; plant development; Plant pathogens; rhizosphere; seed germination; Virulence enhancement; weed control; Frenching disease; Fusarium oxysporum; Parasitic plant management; Natural compounds; Orobanche ramosa; Mycoherbicides; Methionine; Biological control of weeds; Amino acids; Amino acid excretion; Virulence enhancement; Plant pathogens
• ISSN: 1049-9644; 1090-2112
• DOI: 10.1016/j.biocontrol.2005.09.017

Parasitic plants are among the most problematic weeds that are responsible for major losses to many crops. Early growth stages, such as seed germination stimulated by host root exudates and tubercle development, are key phases for the development of these parasites. Inhibition of these early phases by naturally occurring compounds could be a general strategic option for management of parasitic plants. In this study, we report that certain natural amino acids cause severe physiological disorders of germinating broomrape seeds. In particular, methionine was able to inhibit almost totally the germination of seeds of Orobanche ramosa when applied at a concentration of 2 mM. Applied to tomato roots, methionine strongly reduced the number of developing tubercles of the parasite. These findings suggest that: (1) appropriate amino acids applied exogenously to a root zone might result in control of parasitic plants such as Orobanche sp.; (2) amino acid excreting microbes introduced into the crop rhizosphere might control root parasitism; and (3) amino acid producing broomrape pathogens might be selected in order to enhance their virulence.