Abstract
Agrobacterium rhizogenes is a soil bacteria with extensive infectivity, which can infect almost all dicotyledonous plants and a few monocotyledonous plants to induce root nodules. This is caused by the root-inducing plasmid, which contains genes responsible for the autonomous growth of root nodules and crown gall base synthesis. Structurally, it is similar to the tumor-inducing plasmid in that it mainly contains the Vir region, the T-DNA region, and the functional region of crown gall base synthesis. Its T-DNA is integrated into the nuclear genome of the plant with the assistance of Vir genes, causing hairy root disease in the host plant and the formation of hairy roots. The roots produced by Agrobacterium rhizogenes-infested plants are characterized by a fast growth rate, high degree of differentiation, physiological, biochemical, and genetic stability, and ease of manipulation and control. In particular, the hairy root system is an efficient and rapid research tool for plants that have no affinity for transformation by Agrobacterium rhizogenes and low transformation efficiency. The establishment of germinating root culture system for the production of secondary metabolites in the original plants through the genetic transformation of natural plants mediated by root-inducing plasmid in Agrobacterium rhizogenes has become a new technology combining plant genetic engineering and cell engineering. It has been widely used in a variety of plants for different molecular purposes, such as pathological analysis, gene function verification, and secondary metabolite research. Chimeric plants obtained by induction of Agrobacterium rhizogenes that can be expressed instantaneously and contemporarily are more rapidly obtained, compared to tissue culture and stably inheritable transgenic strains. In general, transgenic plants can be obtained in approximately one month.