Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2005
Publication Date: 5/14/2005
Citation: Boue, S.M., Shih, B.Y., Carter Wientjes, C.H., Cleveland, T.E. 2005. Effect of soybean lipoxygenase on volatile generation and inhibition of Aspergillus flavus mycelial growth. Journal of Agricultural and Food Chemistry. 53(12):4778-4783. Interpretive Summary: Volatiles generated from two soybean varieties inhibited the growth of the fungus, Aspergillus flavus. Soybean volatiles were analyzed using a method developed in our laboratory. Twenty-one volatile compounds were detected in one soybean variety. However, only nine volatile compounds were observed in the second soybean variety. Several known antifungal compounds were observed in both soybean varieties. Specific plant pathways may cause the production of these volatile compounds. These results suggest that other factors, other than specific plant pathways, may better explain why soybeans are generally not as severely affected by fungal contamination as other oilseed crops. These results would benefit farmers and researchers at eliminating fungal toxins.
Technical Abstract: Volatiles generated from LOX-normal and LOX-deficient soybean (Glycine max) varieties with and without added lipase inhibited Aspergillus flavus mycelial growth and aflatoxin production. Soybean volatiles were analyzed using a solid phase microextraction (SPME) method combined with gas chromatography-mass spectrometry (GC-MS). Twenty-one compounds, including 11 aldehydes, 3 alcohols, 4 ketones, 1 furan, 1 alkane, and 1 alkene were detected in the LOX-normal soybean line. However, only 9 volatile compounds were observed in the LOX-deficient soybean variety. The antifungal aldehydes hexanal and (E)-2-hexenal were observed in both LOX-normal and LOX-deficient lines, and were detected at significantly higher amounts in soybean homogenate with added lipase. These aldehydes may be formed through alternate pathways, other than the LOX pathway, and may account for the inhibition of A. flavus growth observed. Other volatiles detected, particularly the ketones and alcohols, may contribute to the antifungal activity observed in both LOX-normal and LOX-deficient soybean lines. These results suggest that other factors, other than LOX activity, may better explain why soybeans are generally not as severely affected by A. flavus and aflatoxin contamination as other oilseed crops. These results would benefit farmers and researchers at eliminating aflatoxin from other oilseed crops.