art%3A10.1134%2FS1022795412110130

sonamedo1000

1068

VYACHESLAVOVA et al.

Agrobacterium

vir genes

ChvE

Sugars

Ti plasmid

T-DNA

T-DNA

VirD2

VirA

VirD1/VirD2

VirE2

T-DNA

complex

VirG

Phenols

wounding

integrated

T-DNA

integrated

T-DNA

nucleus

plant

cell

Fig. 1. A diagram of agrobacterial transformation of a plant cell.

tion of a protein product are selected from a large

number of primary transformants.

Several factors are known that influence the efficiency

of agrobacterial transformation of plants.

These are plant genotype, the explants used, the Agrobacterium

strain, composition of nutrient media, conditions

and duration of the interaction of Agrobacterium

and plant explants (inoculation and cocultivation

stages), etc. [7].

The method of Agrobacterium-mediated transformation

of plants has a number of advantages, including

a low number of copies of integrated sequences,

the possibility of transferring large-size sequences, the

possibility of expression of genes encoding multimeric

proteins (e.g., immunoglobulins), and a high level of

stable expression (Table). However, despite the apparent

simplicity of the method, its main limitation is the

dependence of transformation efficiency on plant

genotype. In connection with this, the method often

requires optimization for an individual plant species or

vector construct. Taking into consideration the use of

transgenic plants obtained by agrobacterial transformation

as highly efficient producers of target proteins,

a drawback of this method is an insufficiently high

yield of a target protein relative to the total soluble

protein. Another problem is silencing of target genes

in transgenic plants.

Bioballistic transformation of plants is based on the

physical process of T-DNA delivery. T-DNA contained

in a plant vector is precipitated onto special

metal particles (gold, tungsten), and these particles are

transferred into the plant genome with the use of a

gene gun (bombardment of plant tissue). Thus, the

genes contained in the T-DNA region are integrated

into the plant genome and expressed in the transformed

plant cells. The procedures for selecting transformed

cells and producing from them primary plant

transformants follow the same principle as in the case

of plant transformation with A. tumefaciens. At

present, transgenic plants belonging to different families

of the plant kingdom have been obtained with this

method [8]. Since the time this method was developed

in 1990, numerous bioballistic devices have also

appeared. Different principles of operation and specific

design features of these devices necessitate optimization

of the conditions of ballistic transformation

for every device and every plant species [8].

The efficiency of bioballistic transformation

depends on different factors, which are divided into

three groups: physical, chemical, and biological. The

RUSSIAN JOURNAL OF GENETICS Vol. 48 No. 11 2012