Glutaredoxins regulate maize inflorescence meristem development via redox control of TGA transcriptional activity

OsbZIP47 Is an Integrator for Meristem Regulators During Rice Plant Growth and Development

“…These data show that OsbZIP47 oligomerization is affected by its redox status ( Figure 7B ). Recently, OsbZIP47 maize ortholog, FEA4 was shown to switch its oligomerization status following redox change ( Yang et al, 2021 ). Next, we tested the DNA binding affinity of OsbZIP47 to the TGACGT cis motif (predicted for OsbZIP47 DNA binding) present at around -371 bp upstream of the start codon in the OsFCP1 locus ( Figure 7C ).…”

“…Overall, the results of our qualitative and quantitative data suggest that affinity of OsbZIP 47 FL binding to DNA was redox-dependent despite the absence of the extended Cys rich N-terminal domain commonly found in homologs from other species. Recently, OsbZIP47 close ortholog, ZmFEA4 was shown to interact with three GRX proteins to modulate its redox status and DNA accessibility ( Yang et al, 2021 ).…”

“…Despite being a shorter protein with fewer Cys residues, OsbZIP47 showed redox-dependent DNA binding to OsFCP1 , a downstream gene whose expression was upregulated in OsbZIP47KD panicles. Yang et al (2021) demonstrated that OsbZIP47 maize ortholog, FEA4 interacts with three GRX proteins to modulate its redox status and DNA accessibility proposing a model by which redox status of FEA4 mediate meristem size. In rice, OsGRX19 or MICROSPORELESS1 (OsMIL1) is a potential glutaredoxin redox enzyme for OsbZIP47 as it is a homolog of the glutaredoxin redox enzyme, AtROXY1 and ZmMSCA1 from Arabidopsis and maize, respectively ( Timofejeva et al, 2013 ; Yang et al, 2015 ).…”

“…Like TCP class1, proteins containing cysteines with low pKa values are sensitive to cellular redox status ( Martins et al, 2018 ). Glutaredoxins (GRX) reduce cellular ROS level and interact with different proteins including AtPAN1, ZmFEA4, and OsbZIP47 to modulate their activity by modifying their redox state ( Li et al, 2009 ; Laporte et al, 2012 ; Schippers et al, 2016 ; Hao et al, 2021 ; Yang et al, 2021 ). Arabidopsis pan and maize fea4 mutants exhibited increased meristem size ( Maier et al, 2011 ; Pautler et al, 2015 ).…”

“…Arabidopsis pan and maize fea4 mutants exhibited increased meristem size ( Maier et al, 2011 ; Pautler et al, 2015 ). Contrastingly, single, double, and triple mutations of different GRX paralogs in maize showed progressive reduction of meristem size, proposing a model where GRXs balance redox status and activity of ZmFEA4 to control meristem size ( Yang et al, 2021 ). Interestingly, in transcriptome profiling of OsbZIP47KD panicles, OsGRX6 was downregulated whereas OsGRX16 and OsGRX20 were upregulated ( Supplementary Dataset 1 ), suggesting a mechanism by which OsbZIP47 could be regulating meristem development.…”