straight bind for the PER57 promoter, as a representative example, suggesting that PER genes are downstream target of MYB70 (Figures 7D, 7E and S10). Moreover, the Nav1.4 web transcriptional activity analysis revealed that MYB70 acts as a transcriptional repressor (Figure 7G), downregulating the expression of PER57 (Figure 7F). This outcome as well as that described above for the transcriptional activity assay from the GH3.3 gene indicate that MYB70 has dual transcriptional activities, and may act as both activator and repressor to regulate the expression of its downstream genes. Nonetheless, when the activation function and when the repression function act, this necessary further investigations. The dual functions of TFs in activation or repression of distinctive target genes through direct physical interaction is an interesting phenomenon that has been reported previously, for example for ABI4. ABI4 modulates seed dormancy by straight repressing the transcription of ARR6, ARR7, and ARR15 (Huang et al., 2017), and minimizing ABA degradation via direct repression with the expression of CYP707A1 and CYP707A2, when promoting GA degradation through direct activation of GA2ox7 expression (Shu et al., 2016a, 2016b). In addition, ABI4 also modulates flowering by straight activating Flowering Locus C (FLC) expression (Shu et al., 2016b), although it modulates ROS levels by straight repressing Vitamin C Defective two (VTC2) expression in Arabidopsis (Yu et al., 2019). Outcomes of this study, no less than, suggest that both the activation and repression functions of MYB70 have been activated in parallel for regulation of PR growth of Arabidopsis seedlings via the auxin and ROS signaling pathways (Figures 6 and 7). Also, considering that MYB70 is often a transcriptional repressor using a repression activity of EAR motif (Figure 7G), a co-activator may be needed in addition to MYB70 to activate the expression of GH3 genes. This co-activator should also have the ability to overcome the repression activity of MYB70. It will then be intriguing to find out detailed molecular mechanisms for the dual activities of MYB70 in regulation of plant growth and improvement in a spatiotemporal manner. PERs regulate ROS status in two opposite ways, namely reduction of H2O2 by transferring electrons to donor molecules and formation of O2,by catalyzing the hydroxylic cycle (Passardi et al., 2005; Pitzschke et al., 2006; Tsukagoshi et al., 2010). In OX70 plants, repression of PER gene expression led to decreased O2,and elevated H2O2 accumulation in the roots, specifically in the EZ (Figures 7A, 7B and S9). Even though the phenotype on the PRs of OX70 was comparable to that of 35S:UPB1 (UPB1OX), our final results revealed that the repression of PER gene expression by MYB70 occurred independently of UPB1 (Figure S11). These findings showed that many pathways are involved in the regulation of H2O2/O2,ratio to sustain apical meristem activity within the root guidelines, and MYB70 pathway regulates ROS status at least independently of your UPB1 pathway.iScience 24, 103228, November 19,iScienceArticleIn addition to OX1 Receptor Synonyms modulating cell proliferation and differentiation, PER-mediated ROS status also plays a function within the modification of cell wall structure and initiation of cell expansion, thereby regulating root growth (Passardi et al., 2005; Tsukagoshi et al., 2010). Our transcriptome analysis revealed that as well as PER genes, MYB70 also repressed the transcription of lots of other genes participated in modifying cell wall structure, su
