Control of leaf blade outgrowth and floral organ development by LEUNIG, ANGUSTIFOLIA3 and WOX transcriptional regulators

Abstract

Plant lateral organ development is a complex process involving both transcriptional activation and repression mechanisms. The WOX transcriptional repressor WOX1/STF, the LEUNIG (LUG) transcriptional corepressor and the ANGUSTIFOLIA3 (AN3) transcriptional coactivator play important roles in leaf blade outgrowth and flower development, but how these factors coordinate their activities remains unclear. Here we report physical and genetic interactions among these key regulators of leaf and flower development.We developed a novel in planta transcriptional activation/repression assay and suggest that LUG could function as a transcriptional coactivator during leaf blade development.MtLUG physically interacts with MtAN3, and this interaction appears to be required for leaf and flower development. A single amino acid substitution at position 61 in the SNH domain of MtAN3 protein abolishes its interaction with MtLUG, and its transactivation activity and biological function. Mutations in lug and an3 enhanced each other's mutant phenotypes. Both the lug and the an3 mutations enhanced the wox1 prs leaf and flower phenotypes in Arabidopsis.Our findings together suggest that transcriptional repression and activation mediated by the WOX, LUG and AN3 regulators function in concert to promote leaf and flower development, providing novel mechanistic insights into the complex regulation of plant lateral organ development.

WOX9 functions antagonistic to STF and LAM1 to regulate leaf blade expansion inMedicago truncatulaandNicotiana sylvestris

“…Among the intermediate and ancient clades, AtWOX9 is unique in that it displays the strongest activation activity in dual luciferase assays, and strongly enhances the lam1 mutant phenotype, affecting blade outgrowth in both medial-lateral and proximal-distal axes (Lin et al, 2013), indicating that transcriptional activation activity modulated by AtWOX9 is antagonistic to LAM1 function. This is consistent with the observation that activation activity at the STF expression domain antagonizes STF function in blade outgrowth (Zhang et al, 2014; Zhang et al, 2019).…”

“…Members of this group function primarily as transcriptional repressors, able to complement the lam1 mutant phenotype (Lin et al, 2013), and are capable of substituting for WUS function in maintaining vegetative and floral meristems (Dolzblasz et al, 2016). The WOX1 homologues M. truncatula STF and N. sylvestris LAM1 belong to this clade and function as master regulators of leaf blade outgrowth through a transcriptional repression mechanism in association with the co-repressor TOPLESS (Tadege et al, 2011b; Lin, 2013; Lin et al, 2013; Zhang et al, 2014; Zhang et al, 2019). The intermediate and ancient clade members have partial or no WUS box, and do not have transcriptional repression activity in dual luciferase assays.…”

“…M. truncatula STF or N. sylvestris LAM1 is a transcriptional repressor (Lin, 2013; Lin et al, 2013) and its repression activity is conferred by its WUS box and STF box motifs (Zhang et al, 2014; Zhang and Tadege, 2015). The DNA binding STF homeodomain (HD) and the repression motifs (WUS box and STF box) are critically required for blade outgrowth function (Lin et al, 2013; Zhang et al, 2014; Zhang et al, 2019). Interestingly, all of the WUS clade Arabidopsis WOX transcription factors (WUS and WOX1-WOX7), which have transcriptional repression activity, can substitute for LAM1 function (Lin et al, 2013), suggesting that modern/WUS clade WOX members have a conserved transcriptional repression mechanism in meristem maintenance and lateral organ development, with specificity conferred by cis elements that drive specific expression patterns.…”

Complex Horticultural Quality Traits in Broccoli Are Illuminated by Evaluation of the Immortal BolTBDH Mapping Population

“…Li et al (2009) identified the candidate BrAS1 involved in leaf lamina width. The candidates AtLUG , AtWOX1 , and AtAN3 were shown by Zhang et al (2019) to be involved in leaf blade outgrowth although none of these candidates were identified in LA BCI within BolTBDH. In Arabidopsis , gif1 mutants exhibit a longer, narrow leaf phenotype (Shimano et al, 2018) and a GIF1 homolog (Bo7g093130) collocated within LA_C07@36.6 QTL.…”

ORESARA15 Acts Synergistically with ANGUSTIFOLIA3 and Separately from AINTEGUMENTA to Promote Cell Proliferation during Leaf Growth

“…GIFs have been found to redundantly regulate leaf blade development through cell proliferation regulation [14][15][16], acting in a non-autonomous manner [17]. Recent studies have reported that the AN3/GIF1 protein recruits SWITCH/SUCROSE NONFEREMNTING (SWI/SNF) chromatin remodeling complexes to regulate leaf development [17][18][19].…”