Variation in allyl isothiocyanate production within Brassica species and correlation with fungicidal activity

• Published in: Journal of chemical ecology Vol. 25; no. 12; pp. 2687 - 2701
• Main Authors: OLIVIER, C, VAUGHN, S. F, MIZUBUTI, E. S. G, LORIA, R
• Format: Journal Article
• Language: English
• Published: New York, NY Springer 01.12.1999; Springer Nature B.V
• Subjects: Biological and medical sciences; Brassica juncea; Brassica nigra; Chemical control; Chromatography; Control; Correlation analysis; Flowers & plants; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Fungi; Genotype & phenotype; Pathogens; Phytopathology. Animal pests. Plant and forest protection; Volatile compound; Green manure; Helminthosporium solani; Bioassay; Glucosinolate; Genetic variability; Verticillium dahliae; Plant pathogen; Pesticides; Host agent relation; Biosynthesis; Biological activity; Fungicide; Fungi; Cruciferae; Dicotyledones; Angiospermae; Spermatophyta; Fungi Imperfecti; Brassica nigra; Isothiocyanates; Thallophyta; Brassica juncea
• ISSN: 0098-0331; 1573-1561
• DOI: 10.1023/A:1020895306588

Brassica nigra (black mustard) and B. juncea (Indian mustard) genotypes were tested for pathogen suppression and release of allyl isothiocyanate (AITC), a fungitoxic volatile produced in mustard tissue after enzymatic hydrolysis of allyl glucosinolate (sinigrin). In bioassays, 28 genotypes of B. nigra and 35 genotypes of B. juncea were screened for inhibition of the potato pathogens Helminthosporium solani and Verticillium dahliae by volatiles released from macerated leaf tissue. Release of AITC from plant tissue was quantified by gas chromatography; isothiocyanate profiles were determined by headspace analysis. All mustard genotypes produced compounds that suppressed radial growth of both fungi. Growth suppression and AITC release differed significantly (P < 0.001) among genotypes of B. nigra and B. juncea. Mustard treatments releasing >1.2 mg AITC/g plant tissue were fungicidal to both pathogens. Headspace analysis confirmed that allyl glucosinolate was the major glucosinolate in all genotypes of B. nigra tested; most genotypes also produced 2-phenylethyl-isothiocyanate (ITC). Brassica juncea genotypes produced variable amounts of AITC and other volatiles with antimicrobial activity, including 2-phenylethyl-ITC, benzyl-ITC, and 3-butenyl-ITC. Evaluating mustards from geographically diverse locations allowed selection of mustard genotypes that may be useful in breeding programs designed to develop disease-suppressing green manure cultivars.[PUBLICATION ABSTRACT]