Brassinosteroid Signaling, Crosstalk and, Physiological Functions in Plants Under Heavy Metal Stress

Abstract

Brassinosteroids (BRs) are group of plant steroidal hormones that modulate developmental processes and also have pivotal role in stress management. Biosynthesis of BRs takes place through established early C-6 and late C-6 oxidation pathways and the C-22 hydroxylation pathway triggered by activation of the DWF4 gene that acts on multiple intermediates. BRs are recognized at the cell surface by the receptor kinases, BRI1 and BAK1, which relay signals to the nucleus through a phosphorylation cascade involving phosphorylation of BSU1 protein and proteasomal degradation of BIN2 proteins. Inactivation of BIN2 allows BES1/BZR1 to enter the nucleus and regulate the expression of target genes. In the whole cascade of signal recognition, transduction and regulation of target genes, BRs crosstalk with other phytohormones that play significant roles. In the current era, plants are continuously exposed to abiotic stresses and heavy metal stress is one of the major stresses. The present study reveals the mechanism of these events from biosynthesis, transport and crosstalk through receptor kinases and transcriptional networks under heavy metal stress.

Fine-Tuning Cold Stress Response Through Regulated Cellular Abundance and Mechanistic Actions of Transcription Factors

“…The H 2 O 2 modulated the redox status in cold-stressed plants and increased BZR1 production and CBF genes transcription ( Fang et al, 2021 ). Further, Ca 2+ influx is also reported to be involved in the activation of RBOH1 , hence enhancing the production of ROS ( Kour et al, 2021 ). Apart from that, the expression of CBF could also be controlled by other TFs like ICE1 that activates CBF in response to cold stress.…”

The root apoplastic pH as an integrator of plant signaling

“…Thus, the pH in the cell cortex area is slightly different from the rest of the cytosol and presumably should be tightly regulated to maintain the PMF (Figure 2). Moreover, variations in the cell cortex pH should alter the important cellular processes that occur in this area, such as the cortical microtubules polymerization and depolymerization, and the activation of cell surface receptors and transporters (Lomin et al, 2012;Kour et al, 2021;Lanassa Bassukas et al, 2022). However, we still need to understand this regulation.…”

The dehiscence process in Panax ginseng seeds and the stigmasterol biosynthesis pathway in terms of metabolomics

“…BRs perform “cross-talk” with the key growth-regulating hormones GA 3 and abscisic acid (ABA). BR binding to BRI1 (BRASSINOSTEROID INSENSITIVE 1) leads to heterodimerization with BAK1 (BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED RECEPTOR KINASE 1), and the dimer prohibits the ability of BIN2 (BRASSINOSTEROID INSENSITIVE 2) to phosphorylate BZR1/BES1 (BRASSINAZOLE RESISTANT 1/BRI1-EMS-SUPPRESSOR 1) [ 56 ]. Activated BZR1/BES1 can promote GA 3 biosynthesis and GA 3 degradation of DELLA proteins which then promote the repression of BZR1/BES1 activity.…”