Regulation of DELLA Proteins by Post-translational Modifications

Abstract

DELLA proteins are the negative regulators of the gibberellin (GA) signaling pathway. GAs have a pervasive effect on plant physiology, influencing processes that span the entire life cycle of the plant. All the information encoded by GAs, either environmental or developmental in origin, is canalized through DELLAs, which modulate the activity of many transcription factors or transcriptional regulators. GAs unlock the signaling pathway by triggering DELLA polyubiquitination and degradation by the 26S proteasome. Recent reports indicate, however, that there are other pathways that trigger DELLA polyubiquitination and degradation independently of GAs. Moreover, results gathered during recent years indicate that other post-translational modifications (PTMs), namely phosphorylation, SUMOylation and glycosylation, modulate DELLA function. The convergence of several PTMs in DELLA therefore highlights the strict regulation to which these proteins are subject. In this review, we summarize these discoveries and discuss DELLA PTMs from an evolutionary perspective and examine the possibilities these and other post-translational regulations offer to improve DELLA-dependent agronomic traits.

Illuminating the COP1/SPA Ubiquitin Ligase: Fresh Insights Into Its Structure and Functions During Plant Photomorphogenesis

“…In response to shade and elevated ambient temperatures, COP1 directly targets DELLAs for degradation and thereby promotes plant growth under these conditions ( Blanco-Touriñán et al, 2020a ). DELLAs are also degraded in response to GA via the SLEEPY1 (SLY1) ubiquitin ligase ( Dill et al, 2004 ; Blanco-Touriñán et al, 2020b ). SLY1 and COP1 interact with different domains in the DELLA proteins, suggesting independent mechanisms ( Blanco-Touriñán et al, 2020a ).…”

Genome-wide Analysis and Functional Characterization of the Della Gene Family Associated With Stress Tolerance in B. Napus

“…Intriguingly, the BnRGL2 gene relative expression was not observed in the drought treatment ( Figure 10). Thus, these ndings indicate the presence of unidenti ed cis-elements and signify that the expression of BnDELLAs might be regulated through posttranscriptional modi cation [42,44], which determines the antagonistic and synergistic effects of BnDELLAs in response to environmental uctuations. To further investigate the biological process associated with BnDELLA genes, we had performed the GO enrichment analysis.…”

“…The regulatory purpose of DELLAs and their interacting proteins have been characterized widely in various plant species; however, a possible underlying posttranscriptional modi cation of DELLAs in response to environmental stresses is still unclear [42][43][44]. It has been reported that miRNAs play a signi cant role in transcriptional and post-transcriptional level to modulate gene expression under stresses [45,46].…”

Contrasting Rootstock-Mediated Growth and Yield Responses in Salinized Pepper Plants (Capsicum annuum L.) Are Associated with Changes in the Hormonal Balance

“…In contrast, micrografting experiments between hypocotyls of Arabidopsis wild-type (Col-0) used as scions and GA-deficient mutant rootstocks have induced severe dwarfing and late flowering, suggesting a rootstock-mediated modulation of shoot GA endogenous concentrations [ 35 ]. Since GAs are negatively regulated by DELLA proteins [ 62 ], the ectopic expression of the gain-of-function mutant Mhgai1 encoding a DELLA protein in tomato reduced plant height [ 63 ]. A grafting experiment demonstrated the long-distance movement of Mhgai1 mRNAs and their effect on dwarfing of the scion genotype [ 64 ], as seems to occur in plants grafted onto Terrano.…”