The T-DNA of the Ri-plasmid affects the plant host in such a way, that gene expression is altered, especially in regard to phytohormonal balances, metabolism and certain phenotypical characteristics.
While all types of Ri-plasmid contain T-DNA, the agropine plasmid contains both a TL and a TR-domain (left and right, resp.).
[2] Upon infection with R. rhizogenes and subsequent integration of the Ri-plasmid, the host plant displays phenotypical characteristics aptly named the hairy root disease with the so-called Ri-phenotype.
The phenotypical changes include but are not limited to increased, agravitropic root growth and root hair growth, shortened internodes, wrinkled leaves and reduced apical dominance, dwarfism and early flowering.
Several of these physical traits are of interest in the commercial breeding of horticultural and agricultural plants.