plant disease management. However, in certain cases, along with beneficial
effects, overexpression or repression of various WRKY TFs leads to genetic
drag which needs to be identified and eliminated for most advantageous plant
growth and development. This chapter will be fully focused on the regulation of
the WRKY TFs and its role in plant disease management specifically.
Keywords
Plants · WRKY · Disease · Pathogens · Defense · Bacteria · Virus · Fungi
11.1 Introduction
Every day, the plants face various environmental stresses under the changing
climatic scenario. Among all of the stresses, biotic stresses incited by plant
pathogens especially affect the growth of various plants such as rice, barley,
sugarcane, lentil, faba bean, chickpea (Mehta et al. 2019; Rajput et al. 2017a).
Upon being challenged by phytopathogens, the plants change the growth rate and
pathogenicity of phytopathogen, which leads to the modification of host–pathogen
interaction (Madhusudhan et al. 2019; Rajput et al. 2017b). Because of continuous
changes in climatic conditions, new virulent races or pathovars develop that can
infect the crop resistant to pathogens previously (Rahman et al. 2019; Singh et al.
2019). So, therefore in order to combat these new entities, there is always a pressure/
emphasis to enhance the current or develop new management strategies for
phytopathogens.
However, in order to improve the strategies, the special focus is also given in
understanding changes occurring at the genic, transcriptional, protein, metabolic as
well as the cellular level (Chen et al. 2019; Singh et al. 2018a). The converging point
of all these changes can be traced back to the transcriptional regulation controlled by
transcription factors (TFs). The various TFs related to stress-responsive genes are
WRKY, AP2/ERF, bZIP, MYC, MYB, MADS, NAM, ATAF, CUC, and NAC
(Chen et al. 2019). Each TFs consist of a specific polypeptide binding domain which
binds to a particular sequence/stretch of DNA bases together known as cis-regulatory elements (CREs) in response to specific stress (Mittal et al. 2018).
Among all of the TFs, WRKY TF superfamily is of meticulous importance as
they are reported to be involved in a diverse range of plant development, metabolism, senescence, wounding, etc. (Chen et al. 2019). The WRKY TFs are reported to
be found in higher plants as well as a lower plant with few exceptions (Bakshi and
Oelmüller 2014). The members interact among themselves or with other TFs,
proteins, and small RNAs to regulate the target genes (Chen et al. 2019). With
regard to the discussion in here, WRKY TFs modulation in complex defense gene
network is a key step for signal transduction pathways related to plant immunity.
This results in the PTI, as well as a specific plant pathogen, triggered ETI (Zhang
et al. 2019; Singh et al. 2018b). In both of the processes, salicylic acid (SA) and
jasmonic acid (JA) get modulated at the downstream level. This eventually induces
336
L. S. Rajput et al.
effects, overexpression or repression of various WRKY TFs leads to genetic
drag which needs to be identified and eliminated for most advantageous plant
growth and development. This chapter will be fully focused on the regulation of
the WRKY TFs and its role in plant disease management specifically.
Keywords
Plants · WRKY · Disease · Pathogens · Defense · Bacteria · Virus · Fungi
11.1 Introduction
Every day, the plants face various environmental stresses under the changing
climatic scenario. Among all of the stresses, biotic stresses incited by plant
pathogens especially affect the growth of various plants such as rice, barley,
sugarcane, lentil, faba bean, chickpea (Mehta et al. 2019; Rajput et al. 2017a).
Upon being challenged by phytopathogens, the plants change the growth rate and
pathogenicity of phytopathogen, which leads to the modification of host–pathogen
interaction (Madhusudhan et al. 2019; Rajput et al. 2017b). Because of continuous
changes in climatic conditions, new virulent races or pathovars develop that can
infect the crop resistant to pathogens previously (Rahman et al. 2019; Singh et al.
2019). So, therefore in order to combat these new entities, there is always a pressure/
emphasis to enhance the current or develop new management strategies for
phytopathogens.
However, in order to improve the strategies, the special focus is also given in
understanding changes occurring at the genic, transcriptional, protein, metabolic as
well as the cellular level (Chen et al. 2019; Singh et al. 2018a). The converging point
of all these changes can be traced back to the transcriptional regulation controlled by
transcription factors (TFs). The various TFs related to stress-responsive genes are
WRKY, AP2/ERF, bZIP, MYC, MYB, MADS, NAM, ATAF, CUC, and NAC
(Chen et al. 2019). Each TFs consist of a specific polypeptide binding domain which
binds to a particular sequence/stretch of DNA bases together known as cis-regulatory elements (CREs) in response to specific stress (Mittal et al. 2018).
Among all of the TFs, WRKY TF superfamily is of meticulous importance as
they are reported to be involved in a diverse range of plant development, metabolism, senescence, wounding, etc. (Chen et al. 2019). The WRKY TFs are reported to
be found in higher plants as well as a lower plant with few exceptions (Bakshi and
Oelmüller 2014). The members interact among themselves or with other TFs,
proteins, and small RNAs to regulate the target genes (Chen et al. 2019). With
regard to the discussion in here, WRKY TFs modulation in complex defense gene
network is a key step for signal transduction pathways related to plant immunity.
This results in the PTI, as well as a specific plant pathogen, triggered ETI (Zhang
et al. 2019; Singh et al. 2018b). In both of the processes, salicylic acid (SA) and
jasmonic acid (JA) get modulated at the downstream level. This eventually induces
336
L. S. Rajput et al.