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Team:Harvard/vectors/agro
From 2010.igem.org
abstract lab notebook agrobacteria and plant engineering meet the vectors plant transformation parts & primers references
introduction to agrobacteria
Scientists have known since 1907 that agrobacteria cause tumor formation and other horticultural abnormalities in plants, but it was not until the 1970's that it was discovered that agrobacteria induce these changes by incorporating part of their own genetic material into the plant genome. After binding to plant cells, agrobacteria use genes encoded on a tumor-inducing (Ti) plasmid separate from the bacterial chromosome to transfer a segment of DNA into the plant. These segments are then expressed by the plant to produce hormones that stimulate uncontrolled growth, which induce tumor formation, and to produce opines, amino acid derivatives which serve as a source of carbon and nitrogen for the agrobacteria.
The Ti plasmid contains four main elements: the transfer DNA (T-DNA) region which is transformed into the plant cell and is only expressed by the plant after incorporation into the plant genome, a 30 kb virulence (vir) region which consists of six essential and two accessory operons that are expressed by the agrobacteria to carry out the transfer process, genes responsible for opine catabolism, and genes responsible for transfer of the plasmid during bacterial conjugation. Genes on the bacterial chromosome facilitate binding of the agrobacterium to the plant cell surface, triggering activation of the vir region to initiate transformation.
