MYC2 regulates ARR16, a component of cytokinin signaling pathways, in Arabidopsis seedling development

Abstract

MYC2 is a basic helix‐loop‐helix transcription factor that acts as a repressor of blue light‐mediated photomorphogenic growth; however, it promotes lateral root formation. MYC2 also regulates different phytohormone‐signaling pathways in crucial manner. Arabidopsis response regulator 16 (ARR16) is a negative regulator of cytokinin signaling pathways. Here, we show that MYC2 directly binds to the E‐box of ARR16 minimal promoter and negatively regulates its expression in a cytokinin‐dependent manner. While ARR16 and MYC2 influence jasmonic acid and cytokinin signaling, the expression of ARR16 is regulated by cry1, GBF1, and HYH, the components of light signaling pathways. The transgenic studies show that the expression of ARR16 is regulated by MYC2 at various stages of development. The mutational studies reveal that ARR16 positively regulates the hypocotyl growth in blue light, and phenotypic analysis of atmyc2 arr16 double mutant further reveals that arr16 can suppress the short hypocotyl phenotype of atmyc2. Altogether, this work highlights MYC2‐mediated transcriptional repression of ARR16 in Arabidopsis seedling development.

Evidences for a role of two Y-specific genes in sex determination in Populus deltoides

“…We named this gene FERR (female-specifically expressed RESPONSE REGULATOR), based on evidence for its function described below. Phenotypes previously reported for mutations in two members of this A. thaliana gene family, arr16 and arr17, include effects on plant photomorphogenesis, cell division activity and root hydrotropism, but not changes in floral organs [31][32][33] . However, a recent study demonstrated involvement of such a gene in female functions and sex determination in P. tremula 29 , and named the FERR ortholog ARR17 29 (although, as discussed below, it is not the ortholog of the A. thaliana ARR17 gene).…”

The Z-box binding factors (ZBFs): emerging new facets in Arabidopsis seedling development

“…The phytohormone CK inhibits root growth by promoting cell differentiation in root apical meristem (Vandenbussche et al 2007;Kieber and Schaller 2018). The atmyc2 mutants are less sensitive to the CK induced inhibition of root growth, suggesting a role of MYC2 in CK signaling pathways in regulating the root growth (Shrivastava et al 2019).…”

“…Apart from playing a predominant role in seedling development, the ZBFs have been demonstrated to influence various other developmental processes such as seed germination, root growth, flowering time and senescence (Yadav et al 2005;Mallappa et al 2006;Gangappa et al 2010;Gangappa and Chattopadhyay 2010;Senapati et al 2019). Furthermore, ZBFs also cross-talk with ABA, JA, EL and CK signaling pathways to influence diverse signaling processes (Yadav et al 2005;Kazan and Manners 2013;Gangappa et al 2013b;Zhang et al 2014;Shrivastava et al 2019;Zhuo et al 2019 and Fig. 1).…”

“…A recent study has shown that MYC2 is functionally connected with ARR16 (Arabidopsis Response Regulator 16), a bona fide CK signaling pathway component, in BLmediated photomorphogenic growth (Shrivastava et al 2019). ARR16 encodes a type-A ARR protein that contains a receiver domain at the N-terminal and a short variable C-terminal extension that contains less than 30 amino acids after the receiver domain.…”

“…Root development in Arabidopsis involves a complex regulatory network of transcription factors (Montiel et al 2004;Motte et al 2019). All three ZBFs influence the root growth (Yadav et al 2005;Mallappa et al 2006;Gangappa et al 2010;Prasad et al 2012a;Gupta et al 2014;Maurya et al 2015;Shrivastava et al 2019;Zeb et al;. Studies on influence of ZBFs on root growth places MYC2 high in the functional hierarchy, owing to its strong effect on the root growth (Lorenzo et al 2004;Prasad et al 2012a;Huang et al 2017).…”