1.3
Molecular Mechanisms and Signal Transduction in Stress
The three systematic approaches or three “OMICS” (such as Metabolomics,
Transcriptomics, Proteomics) studies have enhanced the knowledge on how a
plant response at molecular level and what are the complex regulatory mechanisms.
The transcriptomics deals with the RNAs and their expressions. Proteomics studies
about how proteins modify and metabolomics is a tool to study about the
metabolites. The integration of all these three omics has shown various clear
pathways related to concepts of plant responses towards stress (Cramer et al.
2011). Signal perception, transduction, and finally expression of stress response
genes are the three steps at molecular level once the stress is present in environment
(Fig. 1.3). The cascades are associated with reactive oxygen species, Ca
2+ , Abscisic
acid (ABA), Jasmonates (JA), Salicylic acid (SA), Ethylene (ET) which coordinate
various signal pathways. Once the signal is perceived, transduction pathways such as
calcium dependent protein kinase (CDPK), mitogen activated protein kinase
(MAPK) get activated, further down regulating various transcription factors (Baillo
et al. 2019). One example of Ca
2+ signal pathway can be understood in mechanism
of closing of guard cells in drought stress. During drought stress, changes occur in
cytosolic concentration of Ca
2+ which initiates CPK activity resulting into the
release of ABA, which further activates the calcium chelator (BAPTA). When
guard cells receive BAPTA, signal comes to control the transpiration and guard
cell closes (Zou et al. 2015; Atif et al. 2019). Experimental studies on wheat have
shown that CPKs show functional diversity and complexity. The isoforms of closely
ABIOTIC STRESS
STRESS
PERCEPTION
SIGNAL
TRANSDUCTION
TRANSCRIPTION
REGULATION
GENE EXPRESSION
STRESS
TOLERANCE/
RESISTANCE
• ROS, CO
2+
,ABA,JA,
SA, ET
• CDKs, CIKs , MAP
Kinases
• TFs: NAC,
MVB, ERF,
bZIP etc.
• Formation of stress
responsive genes,
Fig. 1.3 Signalling pathway in response to abiotic stress (Modified after Baillo et al. 2019)
10
P. Baweja and G. Kumar
Molecular Mechanisms and Signal Transduction in Stress
The three systematic approaches or three “OMICS” (such as Metabolomics,
Transcriptomics, Proteomics) studies have enhanced the knowledge on how a
plant response at molecular level and what are the complex regulatory mechanisms.
The transcriptomics deals with the RNAs and their expressions. Proteomics studies
about how proteins modify and metabolomics is a tool to study about the
metabolites. The integration of all these three omics has shown various clear
pathways related to concepts of plant responses towards stress (Cramer et al.
2011). Signal perception, transduction, and finally expression of stress response
genes are the three steps at molecular level once the stress is present in environment
(Fig. 1.3). The cascades are associated with reactive oxygen species, Ca
2+ , Abscisic
acid (ABA), Jasmonates (JA), Salicylic acid (SA), Ethylene (ET) which coordinate
various signal pathways. Once the signal is perceived, transduction pathways such as
calcium dependent protein kinase (CDPK), mitogen activated protein kinase
(MAPK) get activated, further down regulating various transcription factors (Baillo
et al. 2019). One example of Ca
2+ signal pathway can be understood in mechanism
of closing of guard cells in drought stress. During drought stress, changes occur in
cytosolic concentration of Ca
2+ which initiates CPK activity resulting into the
release of ABA, which further activates the calcium chelator (BAPTA). When
guard cells receive BAPTA, signal comes to control the transpiration and guard
cell closes (Zou et al. 2015; Atif et al. 2019). Experimental studies on wheat have
shown that CPKs show functional diversity and complexity. The isoforms of closely
ABIOTIC STRESS
STRESS
PERCEPTION
SIGNAL
TRANSDUCTION
TRANSCRIPTION
REGULATION
GENE EXPRESSION
STRESS
TOLERANCE/
RESISTANCE
• ROS, CO
2+
,ABA,JA,
SA, ET
• CDKs, CIKs , MAP
Kinases
• TFs: NAC,
MVB, ERF,
bZIP etc.
• Formation of stress
responsive genes,
Fig. 1.3 Signalling pathway in response to abiotic stress (Modified after Baillo et al. 2019)
10
P. Baweja and G. Kumar