MODD Mediates Deactivation and Degradation of OsbZIP46 to Negatively Regulate ABA Signaling and Drought Resistance in Rice

Abstract

Plants have evolved complicated protective mechanisms to survive adverse conditions. Previously, we reported that the transcription factor OsbZIP46 regulates abscisic acid (ABA) signaling-mediated drought tolerance in rice () by modulating stress-related genes. An intrinsic D domain represses OsbZIP46 activity, but the detailed mechanism for the repression of OsbZIP46 activation remains unknown. Here, we report an OsbZIP46-interacting protein, MODD (Mediator of OsbZIP46 deactivation and degradation), which is homologous to the ABSCISIC ACID-INSENSITIVE5 binding protein AFP. was induced by ABA and drought stress, but the induction was much slower than that of In contrast to OsbZIP46, MODD negatively regulates ABA signaling and drought tolerance, and inhibits the expression of OsbZIP46 target genes. We found that MODD negatively regulates OsbZIP46 activity and stability. MODD represses OsbZIP46 activity via interaction with the OsTPR3-HDA702 corepressor complex and downregulation of the histone acetylation level at OsbZIP46 target genes. MODD promotes OsbZIP46 degradation via interaction with the U-box type ubiquitin E3 ligase OsPUB70. Interestingly, the D domain is required for both deactivation and degradation of OsbZIP46 via its interaction with MODD. These findings show that plants fine-tune their drought responses by elaborate regulatory mechanisms, including the coordination of activity and stability of key transcription factors.

ABI5-BINDING PROTEIN2 Coordinates CONSTANS to Delay Flowering by Recruiting the Transcriptional Corepressor TPR2

“…The transcriptional activity of OsbZIP46 is suppressed by OsMODD by recruiting HADC to OsbZIP46 chromatin to reduce its acetylation level. The protein stability of OsbZIP46 is also regulated by OsMODD through recruitment of the U-box-type ubiquitin E3 ligase OsPUB7 (Tang et al, 2016). Consistent with this finding, we detected a lower CO protein level in the CO-HA/AFP2-ox line than in the CO-HA line during the night (Fig.…”

Antagonistic Transcription Factor Complexes Modulate the Floral Transition in Rice

“…Alternatively (or in parallel), it could fine-tune the production of Hd3a and RFT1 during photoperiodic induction (Gómez-Ariza et al, 2015;Ogiso-Tanaka et al, 2013). More data will be required to distinguish between these possibilities and validate them, but it is clear that reproductive commitment requires a tight balance between flowering promoting and repressive complexes, whose equilibrium could be controlled by modulating the expression levels of distinct bZIPs by developmental or environmental factors (Tang et al, 2016;Wu et al, 2014;Zhang et al, 2016) or by controlling their activity through phosphorylation (Kagaya et al, 2002;Choi et al, 2005;Furihata et al, 2006). Indeed, phosphorylation of OsFD transcription factors is required for binding to 14-3-3 proteins and is limiting to FAC function (Taoka et al, 2011).…”

Transcription factor BnaA9.WRKY47 contributes to the adaptation of Brassica napus to low boron stress by up‐regulating the boric acid channel gene BnaA3.NIP5;1

“…For subcellular localization, the full‐length coding sequence of BnaA9.WRKY47 amplified from ‘Westar 10’ was cloned into the pM999‐33 vector driven by the CaMV35S promoter (Tang et al , ) using the In‐Fusion HD Cloning kit (Takara Bio). The fused construct 35S:BnaA9.WRKY47:GFP was cotransformed with 35S:Ghd7:CFP , a nuclear marker (Tang et al , ), into Arabidopsis protoplasts.…”

“…For subcellular localization, the full‐length coding sequence of BnaA9.WRKY47 amplified from ‘Westar 10’ was cloned into the pM999‐33 vector driven by the CaMV35S promoter (Tang et al , ) using the In‐Fusion HD Cloning kit (Takara Bio). The fused construct 35S:BnaA9.WRKY47:GFP was cotransformed with 35S:Ghd7:CFP , a nuclear marker (Tang et al , ), into Arabidopsis protoplasts. After transformation for 12 to 16 h, a confocal laser‐scanning microscope (Leica SP8) was used for capturing the fluorescence signal with the setting of excitation/detection wavelengths: GFP (488 nm/505–540 nm) and CFP (448 nm/460‐490 nm).…”