Hairy root culture, also called transformed root culture, is a type of

plant tissue culture Plant tissue culture is a collection of techniques used to maintain or grow plant cells, tissues or organs under sterile conditions on a nutrient culture medium of known composition. It is widely used to produce clones of a plant in a method known ...

that is used to study plant metabolic processes or to produce valuable

secondary metabolites Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the nor ...

or recombinant proteins, often with plant

genetic engineering Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including t ...

. A naturally occurring soil bacterium ''

Agrobacterium rhizogenes ''Rhizobium rhizogenes'' (formerly ''Agrobacterium rhizogenes'') is a Gram-negative soil bacterium that produces hairy root disease in dicotyledonous plants. ''R. rhizogenes'' induces the formation of proliferative multiple-branched adventitious ...

'' that contains root-inducing plasmids (also called Ri plasmids) can infect plant roots and cause them to produce a food source for the bacterium,

opines Opines are low molecular weight compounds found in plant crown gall tumors or hairy root tumors produced by pathogenic bacteria of the genus ''Agrobacterium'' and ''Rhizobium''. Opine biosynthesis is catalyzed by specific enzymes encoded by gene ...

, and to grow abnormally. The abnormal roots are particularly easy to culture in artificial media because hormones are not needed in contrast to adventitious roots, and they are

neoplastic A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

, with indefinite growth. The neoplastic roots produced by ''A. rhizogenes'' infection have a high growth rate (compared to untransformed

adventitious roots Important structures in plant development are buds, shoots, roots, leaves, and flowers; plants produce these tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plant ...

), as well as genetic and biochemical stability. Currently the main constraint for commercial utilization of hairy root culture is the development and up-scaling of appropriate (

bioreactors A bioreactor refers to any manufactured device or system that supports a biologically active environment. In one case, a bioreactor is a vessel in which a chemical reaction, chemical process is carried out which involves organisms or biochemistry, ...

) vessels for the delicate and sensitive hairy roots. Some of the applied research on utilization of hairy root cultures has been and is conducted at VTT Technical Research Centre of Finland Ltd. Other labs working on hairy roots are the phytotechnology lab of Amiens University and the Arkansas Biosciences Institute.

Metabolic studies

Hairy root cultures can be used for

phytoremediation Phytoremediation technologies use living plants to clean up soil, air and water contaminated with hazardous contaminants. It is defined as "the use of green plants and the associated microorganisms, along with proper soil amendments and agronomi ...

, and are particularly valuable for studies of the metabolic processes involved in phytoremediation. Further applications include detailed studies of fundamental molecular, genetic and biochemical aspects of genetic transformation and of hairy root induction.

Genetically transformed cultures

The Ri plasmids can be engineered to also contain

T-DNA The transfer DNA (abbreviated T-DNA) is the transferred DNA of the tumor-inducing (Ti) plasmid of some species of bacteria such as ''Agrobacterium tumefaciens'' and ''Agrobacterium rhizogenes(actually an Ri plasmid)''. The T-DNA is transferred fr ...

, used for genetic transformation (biotransformation) of the plant cells. The resulting genetically transformed root cultures can produce high levels of secondary metabolites, comparable or even higher than those of intact plants.

Use in plant propagation

Hairy root culture can also be used for regeneration of whole plants and for production of artificial seeds.

References

{{DEFAULTSORT:Hairy Root Culture Cell culture Plant physiology

Metabolic studies

Genetically transformed cultures

Use in plant propagation

See also

References