Agriculture Reference
In-Depth Information
2050 (Census
2012
). Climate changes in terms of shifting weather patterns will
result in decreased water availability and in conjunction with this, providing food
for this inevitable future population size will be a very hard task without adding
new arable lands (Milly et al.
2005
). To deal with this challenge one of the ma-
jor solutions is plant breeding, which has been used since ancient times in order
to create desired genotypes and phenotypes for specific objectives. The main
goals of conventional plant breeding are improvement of crop yield and quality,
agricultural convenience and resistance to the parasites. While the conventional
plant breeding efforts used in the past were sufficient, nowadays with the increas-
ing demand additional and supplementary technology necessities emerged (Ge-
pts
2002
). As a result of industrial revolution and its reflection to the biological
and agricultural sciences, plant biotechnology reached spectacular success with
understanding of how genes operate and function in plant. The first genetically
modified crops were obtained in the early 1980s by using
Agrobacterium tume-
faciens
following the plant regeneration systems, production of novel chimeric
genes and transformation vectors. Multidisciplinary studies of academic institu-
tions and agricultural seed companies took the leadership on genetic engineering
and biotechnological progresses of crop plants (Özcan et al.
2004
). Although,
many political, regulatory, ethical and religious obstacles are still present, the
adoption rate of crop biotechnology in the area of agriculture is high at global
level. Crop biotechnology involves a different set of technologies such as indus-
trial use of recombinant DNA, cell fusion and tissue engineering.
Agrobacteri-
um
-mediated transformation has always been the most commonly used method
for novel transgenic technologies. Till now, a number of commercially valuable
crops like tomato, potato, rice, wheat, maize, cotton, soybean, alfalfa, barley, car-
rot, sugarcane, pepper and broccoli were obtained using
Agrobacterium
-mediated
transformation (Ozyigit
2012
).
Characteristics of
Agrobacteriumrhizogenes
Certain bacterial species are capable of transferring some of their genes to higher
plants ending up with insertion and permanent integration in the nuclear genome
(Broothaerts et al.
2005
; Kumar et al.
2006
). Members of genus
Agrobacterium
are
widely known for their ability of forming a wide variety of different neoplastic dis-
eases, including crown gall (
A. tumefaciens
and
A. vitis
), hairy root (
A. rhizogenes
)
and cane gall (
A. rubi
) (Gelvin
2009
; Ozyigit
2012
). Among them, the first identi-
fied one was
A. rhizogenes
(formerly
Phytomonas rhizogenes
) in 1930s belonging
to the family Rhizobiaceae in the alpha-2 subclass of Proteobacteria (Riker et al.
1930
; Hildebrand
1934
; Conn
1942
; White
1972
; Kersters and De Ley
1984
; Woese
et al.
1984
; Willems and Collins
1993
).
A. rhizogenes
is a rod-shaped Gram-negative, non-spore forming (0.6-1 μm by
1.5-3.0 μm in size) soil bacterium that occurs singly or in pairs and is motile by
means of one to six peritrichous flagella (Conn
1942
; Meyer et al.
2000
; Tzfira and
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