Co-Authors:
Guenoune, D., Agronomy/Nat. Resources Department, Agricultural Research Organization, Volcani Center, P.O.B 6, Bet Dagan 50250, Israel
Amir, R., Department of Plant Physiology, Migal Technological Center, Kiryat Shmona 12100, Israel
Badani, H., Agronomy/Nat. Resources Department, Agricultural Research Organization, Volcani Center, P.O.B 6, Bet Dagan 50250, Israel
Wolf, S., Institute of Plant Science, Fac. Agric., Food/Environ. Qual. S., Hebrew University of Jerusalem, Rehovot 76100, Israel
Galili, S., Agronomy/Nat. Resources Department, Agricultural Research Organization, Volcani Center, P.O.B 6, Bet Dagan 50250, Israel
Abstract:
Soybean vegetative storage proteins (S-VSPs) are lysine-rich leaf proteins, originally found to accumulate to high levels in depodded soybean plants. In the present study, we overexpressed S-VSPβ, the ruminant stable subunit of the S-VSP genes, in transgenic tobacco plants. The S-VSPβ protein accumulated in all organs studied, but its level declined drastically with leaf age. This instability of S-VSPβ could be overcome either by elevating free lysine levels or by coexpressing S-VSPβ with S-VSPα. High levels of rumen-stable, lysine-rich proteins is expected to improve absorption of lysine by ruminants. Furthermore, the expression of S-VSPs in heterologous plants led to a significant increase in total soluble lysine, suggesting that these proteins may also permit better assimilation of lysine by humans and monogastric animals.