the overexpression, as well as knockout of AtWRKY6 in transgenic plants, helped in
concluding AtWRKY6 has a dual role in supporting and inhibiting virus infection.
Inoculation of Rice stripe virus causes phenotypic symptoms such as stunting,
necrosis, chlorosis, and weakness. In addition, it also covers temporal changes at
the transcriptomic level of protein-synthesis machinery, energy production, cellstructure component synthesis as well as WRKY, AP2, and NAC TF genes (Satoh
et al. 2010). The same trend of results was observed for the defense systems
regulated by WRKY45 upon Rice dwarf virus infection (all three strains,
namely O, D84, and S) (Satoh et al. 2011). Similarly, in another report, it was
confirmed CaWRKY30 is upregulated upon application of TMV, Ralstonia
solanacearum, and P. capsici (Jingyuan et al. 2011). It was also supported by the
work of Naqvi and the group who confirmed the infection of Tomato leaf curl virus
(ToLCNDV) increase, the LeWRKY30 and LePR-1 in tomato (Naqvi et al. 2011).
With WRKY domain-specific differential display protocol, the CaWRKYb and
CaWRKYd genes were identified which get rapidly induced upon TMV inoculation.
Later, the overexpression and knockout studies revealed the positive roles of
CaWRKYb and CaWRKYd in the hypersensitive response between hot pepper
(Cv. Bugang) and TMV (pathotype P0) (Huh et al. 2012).
Using Bean pod mottle virus-based VIGS technology, the role of WRKY6, as well
as WRKY30 in Rsv1-mediated resistance, was elucidated in soybean (Zhang et al.
2012). In another article, mild infection of Citrus tristeza virus isolate in sweet
Citrus aurantifolia also upregulated the WRKY TFs and ethylene-responsive element binding factors (ERFs) profiles confirmed with suppression subtractive
hybridization (Liu et al. 2012). Similarly, the overexpression of cotton GhWRKY15
and GhWRKY11 in transgenic tobacco plants activated the expression of several PR,
POD, and APX genes, therefore, triggering systemic acquired resistance (SAR) to
protect the plant against viral pathogens such as TMV and cucumber mosaic virus
(CMV) as compared with the wild-type (Sun et al. 2012). The similar role of WRKY
TF (AtWRKY8) also has been elucidated in the defense response to crucifer-infecting
TMV. The reason lies in the mediatory role of AtWRKY in ET and ABA signaling
crosstalk (Chen et al. 2013a). In another published article, a total of 16 WRKY genes
were downregulated even up to 7.9-fold in the Tomato yellow leaf curl virus
(TYLCV)-susceptible tomato line (TMXA48-4-0). However, there were nearly
7 WRKY genes upregulated in the TYLCV-resistant CLN2777A line (Chen et al.
2013b). Inoculation of Rice tungro spherical virus (RTSV) on susceptible rice
(Cv. TN1) changed the transcripts levels of multiple stress-related genes including
multiple members of the WRKY gene family (OsWRKY1.V2, OsWRKY5,
OsWRKY9, OsWRKY28, OsWRKY29, and OsWRKY45) (Satoh et al. 2013).
In their extensive work, the expression profiles of 13 selected papayas genotypes,
CpWRKY TF genes under both two biotic and three abiotic stresses were evaluated
through qRT-PCR. The expression levels of TF12.199, TF807.3, TF21.156, and
TF18.51 were notably induced by the Papaya ringspot virus (Pan and Jiang 2014).
Later, focus was also done on finding the common WRKY TFs coding genes in
induced plant expression profiles by multiple viruses like Potato virus Y, TMV, and
CMV through using databases, online literature, and quantitative analyses. Data
11 Role of WRKY Transcription Factor Superfamily in Plant Disease Management
343
concluding AtWRKY6 has a dual role in supporting and inhibiting virus infection.
Inoculation of Rice stripe virus causes phenotypic symptoms such as stunting,
necrosis, chlorosis, and weakness. In addition, it also covers temporal changes at
the transcriptomic level of protein-synthesis machinery, energy production, cellstructure component synthesis as well as WRKY, AP2, and NAC TF genes (Satoh
et al. 2010). The same trend of results was observed for the defense systems
regulated by WRKY45 upon Rice dwarf virus infection (all three strains,
namely O, D84, and S) (Satoh et al. 2011). Similarly, in another report, it was
confirmed CaWRKY30 is upregulated upon application of TMV, Ralstonia
solanacearum, and P. capsici (Jingyuan et al. 2011). It was also supported by the
work of Naqvi and the group who confirmed the infection of Tomato leaf curl virus
(ToLCNDV) increase, the LeWRKY30 and LePR-1 in tomato (Naqvi et al. 2011).
With WRKY domain-specific differential display protocol, the CaWRKYb and
CaWRKYd genes were identified which get rapidly induced upon TMV inoculation.
Later, the overexpression and knockout studies revealed the positive roles of
CaWRKYb and CaWRKYd in the hypersensitive response between hot pepper
(Cv. Bugang) and TMV (pathotype P0) (Huh et al. 2012).
Using Bean pod mottle virus-based VIGS technology, the role of WRKY6, as well
as WRKY30 in Rsv1-mediated resistance, was elucidated in soybean (Zhang et al.
2012). In another article, mild infection of Citrus tristeza virus isolate in sweet
Citrus aurantifolia also upregulated the WRKY TFs and ethylene-responsive element binding factors (ERFs) profiles confirmed with suppression subtractive
hybridization (Liu et al. 2012). Similarly, the overexpression of cotton GhWRKY15
and GhWRKY11 in transgenic tobacco plants activated the expression of several PR,
POD, and APX genes, therefore, triggering systemic acquired resistance (SAR) to
protect the plant against viral pathogens such as TMV and cucumber mosaic virus
(CMV) as compared with the wild-type (Sun et al. 2012). The similar role of WRKY
TF (AtWRKY8) also has been elucidated in the defense response to crucifer-infecting
TMV. The reason lies in the mediatory role of AtWRKY in ET and ABA signaling
crosstalk (Chen et al. 2013a). In another published article, a total of 16 WRKY genes
were downregulated even up to 7.9-fold in the Tomato yellow leaf curl virus
(TYLCV)-susceptible tomato line (TMXA48-4-0). However, there were nearly
7 WRKY genes upregulated in the TYLCV-resistant CLN2777A line (Chen et al.
2013b). Inoculation of Rice tungro spherical virus (RTSV) on susceptible rice
(Cv. TN1) changed the transcripts levels of multiple stress-related genes including
multiple members of the WRKY gene family (OsWRKY1.V2, OsWRKY5,
OsWRKY9, OsWRKY28, OsWRKY29, and OsWRKY45) (Satoh et al. 2013).
In their extensive work, the expression profiles of 13 selected papayas genotypes,
CpWRKY TF genes under both two biotic and three abiotic stresses were evaluated
through qRT-PCR. The expression levels of TF12.199, TF807.3, TF21.156, and
TF18.51 were notably induced by the Papaya ringspot virus (Pan and Jiang 2014).
Later, focus was also done on finding the common WRKY TFs coding genes in
induced plant expression profiles by multiple viruses like Potato virus Y, TMV, and
CMV through using databases, online literature, and quantitative analyses. Data
11 Role of WRKY Transcription Factor Superfamily in Plant Disease Management
343