TITLE:
The Concentration of 2-Propenyl Glucosinolate in Biofumigant Crops Influences Their Anti-Fungal Activity (In-Vitro) against Soil-Borne Pathogens
AUTHORS:
Oscar Villalta, Denise Wite, David A. Riches, Jorge Guiano, Vijey Chandolu, Cassie Scoble, Caroline Donald, Ian J. Porter, Scott W. Mattner
KEYWORDS:
Brassica, Glucosinolate, Soilborne Disease, Biofumigation, Sclerotinia
JOURNAL NAME:
Journal of Agricultural Chemistry and Environment,
Vol.5 No.1B,
April
30,
2016
ABSTRACT:
This study investigated the biofumigation
potential of nine Brassica species/cultivars by determining the levels of
2-propenyl glucosinolate in their roots and shoots, and their in-vitro suppression
of four major soil-borne pathogens of vegetable crops. Hydrolysis of 2-propenyl
GSL produces volatile isothiocyanate (ITC) compounds which are known to have
anti-fungal activity. HPLC results showed that 2-propenyl GSL only occurred in
root and shoot residue of flowering plants of four Brassica cultivars developed
for green manuring (Caliente 199?, Mustclean?, Nemfix? and BQ Mulch?) and in
the standard (mustard seed meal) treatment Fumafert?. Levels of 2-propenyl GSL
varied several fold within the four Brassica cultivars, with 77-88% of the
total concentrations recorded in the shoot tissues. In in vitro assays, the
level of fungal suppression by volatiles emitted by hydrated shoot and root
residues related to their content of 2-propenyl GSL, and the dose of residue
applied to five soilborne test pathogens (S. minor, Rhizoctonia solani, Fusarium
oxysporum, Pythium dissotocum and Rhizoctonia solani). The variation in
2-propenyl GLS levels found in the Brassica green manure crops tested provides
scope for selecting cultivars with greater potential for biofumigation, and to
control multiple soil-borne disease problems in vegetable farms.