Submitted to: Plant Cell Reports
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/19/2001
Publication Date: N/A
Citation: Interpretive Summary: Soybeans are relatively insensitive to infection by Agrobacterium tumefaciens, a bacteria that has proven useful as a vehicle to modify genetically model plants such as tobacco, petunia and thale cress. The insensitivity of soybean to infection by Agrobacterium has frustrated efforts to improve them by genetic engineering. In this manuscript evidence is described that shows certain thiol-containing chemicals such a cysteine and dithiothreitol promote the infection of wounded cotyledonary nodes of soybean by Agrobacterium. When present during the infection process, these thiol-compounds increase the recovery of recombinant soybeans that contain marker genes transferred from the bacterium. The observation will be useful to scientists that seek to genetically engineer soybean.
Technical Abstract: Agrobacterium-mediated T-DNA delivery and the production of fertile transgenic soybean plants using the cotyledonary-node method were improved by amending the solid co-cultivation medium with L-cysteine. The goal of this study was to investigate the role of cysteine in increasing T-DNA delivery. T-DNA delivery was increased only when L-cysteine was present during Agrobacterium and plant interactions. This effect was due to the thiol group since D-cysteine and other thiol compounds also increased T-DNA very. Copper and iron chelators also increased T-DNA delivery, indicating an association with inhibition of polyphenol oxidase and peroxidase. Thiol compounds likely inhibit wound and pathogen induced responses, thereby increasing T-DNA delivery into soybean cells. The increases in T-DNA delivery were independent of soybean genotype, Agrobacterium strain, and binary plasmid.