Arabidopsis DDB1-CUL4 E3 ligase complexes in det1 salt/osmotic stress resistant germination

Abstract

A key regulatory mechanism in plant growth, development, and stress signaling utilizes E3 ubiquitin ligases, which target a variety of substrates for degradation. DE-ETIOLATED 1 (DET1) forms a complex with DDB1 (DAMAGED DNA BINDING protein 1) and CUL4 (CULLIN 4), and negatively regulates light signaling. Another DDB1-CUL4 complex containing DWA1 and DWA2 (DWD hypersensitive to ABA 1 and 2) has been shown to negatively regulate abscisic acid (ABA) signaling. Since distinct DDB1-CUL4 complexes have been shown to influence each other, we analyzed genetic interactions between DET1 and components of DDB1-CUL4 complexes during seed germination under salt and osmotic stress conditions. det1 germination was resistant to salt and osmotic stress and dwa1 and dwa2 enhanced this phenotype. In contrast, ddb1a partially suppressed the det1 germination phenotype on both salt and mannitol, while ddb1b had no effect. Mutations in DDB2, a DDB1-CUL4 complex component involved in DNA repair, also partially suppressed the det1 germination phenotype while mutants in COP1, another light signaling component, completely suppressed the det1 resistant germination phenotypes. Taken together these data suggest that components of E3 ubiquitin ligase complexes have variable but significant effects on det1 salt/osmotic stress responses.

Integrative Transcriptomics Data Mining to Explore the Functions of TDP1α and TDP1β Genes in the Arabidopsis thaliana Model Plant

“…The CDD complex negatively regulates ABA responses, leading to the degradation of ABA receptors. It has been hypothesized that ABA coordinates and regulates the greening of seedlings through a process in which three main proteins are involved: DET1, histone deacetylase 6 (HDA6), and far-red elongated hypocotyl 3 (FHY3) [ 72 ].…”

OsCBE1, a Substrate Receptor of Cullin4-Based E3 Ubiquitin Ligase, Functions as a Regulator of Abiotic Stress Response and Productivity in Rice

“…OsCBE1 belongs to non-DWD DCAFs, which was first shown in rice. It has been reported that DCAFs of ABD1 [ 42 ], ASG2 [ 43 ], DET1-DDA1 complex [ 44 , 45 ], DRS1 [ 46 ] DWA1, DWA2 [ 32 ], DWA3 [ 47 ], HOS15 [ 48 ], RAE1 [ 49 ], and WDR55 [ 50 ] regulate the ABA signaling pathway. With ABD1, OsCBE1 is another non-DWD type DCAF protein related to the ABA pathway.…”

Enhanced Reproductive Thermotolerance of the Tomato high pigment 2 Mutant Is Associated With Increased Accumulation of Flavonols in Pollen

“…Interestingly, ubiquitin ligases, which contain DET1 as a complex unit, were suggested to play a role in abiotic stress responses as they mediate ABA signaling in Arabidopsis ( Irigoyen et al, 2014 ; Seo et al, 2014 ). The involvement of DET1 in abiotic stress tolerance was further demonstrated by improved seeds germination of the det1 Arabidopsis mutant under salt and osmotic stress conditions ( Fernando and Schroeder, 2016 ). However, the possible effect of the tomato det1 ( hp2 ) mutant on abiotic stress response or stress tolerance was not evaluated prior to this study.…”