Molecular Plant Breeding 2015, Vol.6, No.20, 1
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related to transcriptional regulation. These genes came
down to a variety of transcriptional regulation
pathway, consisting of transcription factor of MYB
and MYC, zinc finger protein, retrotransposon,
Glycine-rich RNA binding protein, and so on.
The transcription factors (TFs) play an important role
in the regulating gene expression by activating or
suppressing the gene expression, such as plant growth
and development, morphogenesis, as well as its
response to environment. Plant TFs control gene
expressions and genes control many physiological
processes, which in turn trigger cascades of biochemical
reactions in plant cells. Studies had shown that the
plant transcription factors that played an important
role in plant stress-resistance response could regulate
the expression of genes related to pathogen, drought,
high salinity, low temperature, hormone, and so on.
Now, there are 129, 288 plant transcription factors
identified from 83 species and classified them into 58
families (Zhang et al., 2011). According to the difference
of the conservative DNA-binding domain, the
transcription factors is divided into the following
catrgories: MYB
、
AP2
、
NAC
、
MYC
、
HD
、
C2H2(Zn)
、
ARF
、
WRKY, and so on.
In the family of transcription factor, MYB is the most
one and the function of MYB is the most diverse.
They play an important role in regulating plant stress
responses. When the plant is forced by biological
stress including pathogen or insect damage, for
example, the overexpression of TiMYB2R-1 may be
used for improving take-all resistance of wheat and
other cereal crops (Liu et al., 2013). Hypersensitive
response (HR) is a cell programmed death process
related to plant resistance to diseases. Salicylic acid
(SA) plays an important role in resisting pathogen
infection. When plant is induced by pathogens, plant
has two main types of systemic resistance, one is
system acquired resistance (SAR) dependent on
salicylic acid, and for example,
AtMyb30
in Arabidopsis is
a MYB
transcription factor gene of special transient
expression in the early HR. Through the transgenic
experiment for
AtMyb30
of overexpression and
suppression in Arabidopsis and tobacco, it turned to
be
AtMyb30
acts as a positive regulator of the HR
(Vailleau et al., 2002).
AtMyb30
expression in response to
an HR-inducing bacterial pathogen is dependent on
SA accumulation, but NPR1-independent, and
alterations of
AtMyb30
expression modulate SA levels
and SA-associated gene expression (Raffaele et al.,
2006). The other is induced systematic resistance (ISR)
dependent on jasmonic acid (JA) and ethylene (ET).
Some MYB transcription factors may be activated in
signal molecules JA and defense response, which in
turn regulates later resistance-associated gene
overexpression, and reduces the damage of pathogens.
The MYC transcription factor also is an important
type in transcription factor family. The study showed
that AtMYC2 could be induced rapidly by exogenous
ABA or drought treatments, and AtMYC2 could
interact with AtMYB2 (Abe et al., 2003). AtMYC2
differentially regulates the expression of two groups
of JA-induced genes. The first group includes genes
involved in defense responses against pathogens and is
repressed by AtMYC2. The second group, integrated by
genes involved in JA-mediated systemic responses to
wounding, is activated by AtMYC2 (Lorenzo et al.,
2004).
The zinc finger proteins are a super family of proteins
involved in numerous activities of plant growth and
development and are also known to regulate resistance
mechanism for various biotic and abiotic stresses
(Feurtado et al., 2011). Because of its special
finger-like structure, the zinc finger protein plays an
important role in the identification of DNA, protein
and RNA, in addition to transcription factors and
protein adapter, some zinc finger proteins also have
RNA binding properties and regulate the transcription
of target genes. There were thirty four zinc finger
domains identified in the R proteins of nine crops and
were grouped into 19 types of zinc fingers. The size of
individual zinc finger domain within the R genes
varied from 11 to 84 amino acids, whereas the size of
proteins containing these domains varied from 263 to
1305 amino acids (Gupta et al., 2012). In our study,
the transcription factor of MYB and MYC, zinc finger
protein and other genes-associated were found. This
suggests that MYB, MYC and zinc finger protein are
involved in the response and regulation of the
interaction between banana and Foc-TR4.
The special genes relevant to signal transduction
When banana is infected by Foc-TR4, how the
pathogenic infection signal is transferred into cell,
which is one of the great concerns of this study. The
