Effect of fungal damage by Fusarium spp and Diaporthe/Phomopsis complex on protein quantity and quality of soybean seed

Seeds from three soybean genotypes were tested to evaluate the effect of fungal damage by Fusarium spp and Diaporthe/Phomopsis complex on protein quantity and quality. Fungus‐infected seeds had higher protein contents than uninfected ones. A selective degradation of soluble proteins was detected in seeds infected with either fungus. Some of the storage proteins degraded were identified as α′, α and β subfractions of the β‐conglycinin, and A₃ subfraction of the glycinin. Furthermore, reductions in lipoxygenase and trypsin inhibitor activities were observed in fungus‐infected seeds. Amino acid composition did not vary between infected and uninfected seed lots, so protein degradation should not affect amino acid structures. Copyright © 2004 Society of Chemical Industry