Project description:DAP-seq was used to generate genome-wide DNA:TF interaction maps for fourteen maize ARFs from the evolutionarily conserved class A ‘activator’ and class B ‘repressor’ clades. Among the distinct binding sites that were identified, we observed a high degree of overlap for ARFs of the same class, but found substantial differences in motif sequence, spacing, site preference, and association with auxin induced genes among clade A and clade B ARFs.
Project description:DAP-seq was used to generate genome-wide DNA:TF interaction maps for fourteen maize ARFs from the evolutionarily conserved class A ‘activator’ and class B ‘repressor’ clades. Among the distinct binding sites that were identified, we observed a high degree of overlap for ARFs of the same class, but found substantial differences in motif sequence, spacing, site preference, and association with auxin induced genes among clade A and clade B ARFs.
Project description:In order to elucidate the molecular mechanism of auxin-induced mesocotyl elongation, gene expression profiling analyses were performed in a deep-sowing tolerant maize inbred line 3681-4. Gene expression studies combing Affymetrix GeneChip analysis and Real-time PCR were employed to determine the molecular mechanism underlying IAA promotion of maize mesocotyl elongation. Under deep-sowing condition, IAA is transported by auxin transporter-like protein 1 and binds to auxin binding protein ABP20, which results in degradation of Aux/IAA and de-repressing of auxin-inducible genes. Then, transcriptional factor such as MYB, kinase such as LRR, fructose and mannose metabolism and so on are activated. Finally, genes involved in cell wall synthesis and modification are expressed so that mesocotyl elongation of 3681-4 is promoted. Furthermore, gene expression of a key enzyme ACO in ethylene biosynthesis and ethylene receptor ETR2 were up-regulated after the treatment with 10-4 M IAA, which suggested that mesocotyl elongation of 3681-4 inclined to be inhibited when the concentration of applied IAA was increased from 10-4 M to 10-3 M. In two independent experiments, we generate 10-day-old maize mesocotyl-specific gene expression profiles through comparing genome-wide expression patterns of IAA treatment and TIBA (an auxin transportation inhibitor) treatment under 20 cm deep-sowing condition in darkness by using 17,555 Affymetrix maize whole genome array.
Project description:Directional transport of auxin is critical for inflorescence and floral development in flowering plants, but the role of auxin influx carriers (AUX1 proteins) has been largely overlooked. Taking advantage of available AUX1 mutants in Setaria viridis and maize, we uncover previously unreported aspects of plant development that are affected by auxin influx, including higher order branches in the inflorescence, stigma branch number, and glume (floral bract) development, and plant fertility. However, disruption of auxin flux does not affect all parts of the plant, with little obvious effect on inflorescence meristem size, time to flowering, and anther morphology. In double mutant studies in maize, disruptions of ZmAUX1 also affect vegetative development. A GFP-tagged construct of SvAUX1 under its native promoter showed that the AUX1 protein localizes to the plasma membrane of outer tissue layers in both roots and inflorescences, and accumulates specifically in inflorescence branch meristems, consistent with the mutant phenotype and expected auxin maxima. RNA-seq analysis finds that most gene expression modules are conserved between mutant and wildtype plants, with only a few hundred genes differentially expressed in spp1 inflorescences. Using CRISPR-Cas9 technology, we disrupted SPP1 and the other four AUX1 homologs in S. viridis. SvAUX1/SPP1 has a larger effect on inflorescence development than the others, although all contribute to plant height, tiller formation, leaf, and root development. The AUX1 importers are thus not fully redundant in S. viridis. Our detailed phenotypic characterization plus a stable GFP-tagged line offer tools for future dissection of the function of auxin influx proteins.
Project description:In order to elucidate the molecular mechanism of auxin-induced mesocotyl elongation, gene expression profiling analyses were performed in a deep-sowing tolerant maize inbred line 3681-4. Gene expression studies combing Affymetrix GeneChip analysis and Real-time PCR were employed to determine the molecular mechanism underlying IAA promotion of maize mesocotyl elongation. Under deep-sowing condition, IAA is transported by auxin transporter-like protein 1 and binds to auxin binding protein ABP20, which results in degradation of Aux/IAA and de-repressing of auxin-inducible genes. Then, transcriptional factor such as MYB, kinase such as LRR, fructose and mannose metabolism and so on are activated. Finally, genes involved in cell wall synthesis and modification are expressed so that mesocotyl elongation of 3681-4 is promoted. Furthermore, gene expression of a key enzyme ACO in ethylene biosynthesis and ethylene receptor ETR2 were up-regulated after the treatment with 10-4 M IAA, which suggested that mesocotyl elongation of 3681-4 inclined to be inhibited when the concentration of applied IAA was increased from 10-4 M to 10-3 M.
Project description:In maize, nitrate regulates root development thanks to the coordinated action of many players. In this study, the involvement of SLs and auxin as putative downstream components of the nitrate regulation of lateral root development was investigated. To this aim, the endogenous SL content of maize root in response to nitrate availability was assessed by means of LC-MS/MS and measurements of lateral root density in the presence of analogues or inhibitors of auxin and strigolactones were performed. Furthermore, un untargeted RNA-seq based approach was used to better characterize the participation of auxin and strigolacotones to the transcriptional signature of maize root response to nitrate. Our results suggested that N deprivation toughly induces zealactone and carlactonoic acid biosynthesis in maize root, to a higher extent if compared to P-deprived roots. Moreover, data on lateral root density led to hypothesise the existence of both auxin-dependent and auxin-independent effects of nitrate on LR development. In addition, the inhibition of SL biosynthesis seems to participate to the auxin-dependent induction of LR, but the involvement of further downstream unknown components cannot be ruled out.