Abstract
Plants are adapted to sense numerous stress stimuli and mount efficient defense responses by directing intricate signaling pathways. They respond to undesirable circumstances to produce stress-inducible phytochemicals that play indispensable roles in plant immunity. Extensive studies have been made to elucidate the underpinnings of defensive molecular mechanisms in various plant species. Transcriptional factors (TFs) are involved in plant defense regulations through acting as mediators by perceiving stress signals and directing downstream defense gene expression. The cross interactions of TFs and stress signaling crosstalk are decisive in determining accumulation of defense metabolites. Here, we collected the major TFs that are efficient in stress responses through regulating secondary metabolism for the direct cessation of stress factors. We focused on six major TF families including AP2/ERF, WRKY, bHLH, bZIP, MYB, and NAC. This review is the compilation of studies where researches were conducted to explore the roles of TFs in stress responses and the contribution of secondary metabolites in combating stress influences. Modulation of these TFs at transcriptional and post-transcriptional levels can facilitate molecular breeding and genetic improvement of crop plants regarding stress sensitivity and response through production of defensive compounds.
Highlights
Plants are surrounded by a myriad of diverse phytopathogens along with their sessile nature under continuously fluctuating environmental conditions
In the context of Transcriptional factors (TFs) interactions, several heteromutimeric protein complexes are involved in stress response through mediating secondary metabolism, such as the MYB-bHLH-WDR complex in Arabidopsis that plays the crucial role for the biosynthesis of flavonoids [116]
In response to these diverse biotic/abiotic stresses, plants perceive these adverse cues through different sensors/receptors, which undergo structure transformation/modification upon acceptance of exogenous ligands, and transfer signals to downstream processes
Summary
Plants are surrounded by a myriad of diverse phytopathogens along with their sessile nature under continuously fluctuating environmental conditions. We reviewed a thorough perspective of plant stress responses involving secondary metabolism regulated by TFs. Following are six transcriptional families (AP2/ERF, WRKY, bHLH, bZIP, MYB, and NAC) that are involved in biotic and abiotic stress responses through mediating biosynthesis and accumulation of secondary metabolites. Both of TcERF12 and TcERF15 were bound to the cis-element GCC-box on the tasy gene promoter to regulate taxol biosynthesis Another class of anti-microbial metabolite is hydroxycinnamic acid amide (HCAA) that confers plant defense against Alternaria brassicicola and Botrytis cinerea. The HCAA biosynthetic gene, AtACT (agmatinecoumaryl transferase) has been reported to be regulated by ORA59 through the bindingto two GCC boxes of AtACT promoter in MED25 dependent regulation [63], resulting in high accumulation of HCAAs in Arabidopsis plants It shows that transcription factor regulation is complex and dependent on additional factors for proper accumulation of defense metabolites. Roles of the AP2/ERF transcriptional family have been excessively studied against biotic stresses in the past five years that clues their less involvement in abiotic stress responses (Table 1)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
