Coexpression of the soybean vegetative storage protein beta subunit (S-VSPbeta) either with the bacterial feedback-insensitive dihydrodipicolinate synthase or with S-VSPalpha stabilizes the S-VSPbeta transgene protein and enhances lysine production in transgenic tobacco plants.
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-VSPbeta, the ruminant stable subunit of the S-VSP genes, in transgenic tobacco plants. The S-VSPbeta protein accumulated in all organs studied, but its level declined drastically with leaf age. This instability of S-VSPbeta could be overcome either by elevating free lysine levels or by coexpressing S-VSPbeta with S-VSPbeta. 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.
Guenoune
Dana
D
Agronomy and Natural Resources Department, Agricultural Research Organization, The Volcani Center, P.O.B 6, Bet Dagan 50250, Israel.
Amir
Rachel
R
Badani
Hanna
H
Wolf
Shmuel
S
Galili
Shmuel
S
D000818:Animals; D002736:Chloroplasts / Q000378:metabolism; D005246:Feedback; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D006801:Humans; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism*; D008239:Lysine / Q000096:biosynthesis*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D013025:Glycine max; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D019076:Transgenes / Q000235:genetics*
D010940:Plant Proteins; C078148:VSPA protein, Glycine max; C078149:vspB protein, Glycine max; D006836:Hydro-Lyases; C020040:4-hydroxy-tetrahydrodipicolinate synthase; D008239:Lysine