Project description:The floral transition in Arabidopsis is tightly controlled by complex genetic regulatory networks in response to endogenous and environmental flowering signals. SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) and SHORT VEGETATIVE PHASE (SVP), two key MADS-domain transcription factors, perceive these signals and function as antagonistic flowering regulators. To understand how they mediate the floral transition, we mapped in vivo binding sites of SOC1 and SVP using chromatin immunoprecipitation followed by hybridization to whole-genome tiling arrays (ChIP-chip). Genes encoding proteins with transcription regulator activity and transcription factor activity were the most enriched groups of genes bound by SOC1 and SVP, indicating their central roles in flowering regulatory networks. In combination with gene expression microarray studies, we further identified the genes whose expression was directly regulated by SOC1 or SVP. Among the common direct targets identified, APETALA2 (AP2)-like genes that repress FT and SOC1 expression were downregulated by SOC1, but upregulated by SVP, revealing a complex feedback regulation among key genes determining the integration of flowering signals. SOC1 regulatory regions were also accessed by SOC1 itself and SVP, suggesting that self-activation and repression by SVP contribute to the regulation of SOC1 expression. In addition, ChIP-chip analysis demonstrated that miR156e and miR172a, which are involved in the regulation of AP2-like genes, were direct targets of SOC1 and SVP, respectively. Taken together, these findings reveal that feedback regulatory loops mediated by SOC1 and SVP are essential components of the gene regulatory networks underpinning the integration of flowering signals during the floral transition. soc1-101D and 35S:SVP ChIPed with SOC1 or SVP polyclonal antibody respectively vs. soc1-2 or svp-41 in Arabidopsis 9-day-old whole seedlings
Project description:The floral transition in Arabidopsis is tightly controlled by complex genetic regulatory networks in response to endogenous and environmental flowering signals. SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) and SHORT VEGETATIVE PHASE (SVP), two key MADS-domain transcription factors, perceive these signals and function as antagonistic flowering regulators. To understand how they mediate the floral transition, we mapped in vivo binding sites of SOC1 and SVP using chromatin immunoprecipitation followed by hybridization to whole-genome tiling arrays (ChIP-chip). Genes encoding proteins with transcription regulator activity and transcription factor activity were the most enriched groups of genes bound by SOC1 and SVP, indicating their central roles in flowering regulatory networks. In combination with gene expression microarray studies, we further identified the genes whose expression was directly regulated by SOC1 or SVP. Among the common direct targets identified, APETALA2 (AP2)-like genes that repress FT and SOC1 expression were downregulated by SOC1, but upregulated by SVP, revealing a complex feedback regulation among key genes determining the integration of flowering signals. SOC1 regulatory regions were also accessed by SOC1 itself and SVP, suggesting that self-activation and repression by SVP contribute to the regulation of SOC1 expression. In addition, ChIP-chip analysis demonstrated that miR156e and miR172a, which are involved in the regulation of AP2-like genes, were direct targets of SOC1 and SVP, respectively. Taken together, these findings reveal that feedback regulatory loops mediated by SOC1 and SVP are essential components of the gene regulatory networks underpinning the integration of flowering signals during the floral transition.
Project description:MADS-domain transcription factors play pivotal roles in numerous developmental processes in Arabidopsis thaliana. While their involvement in flowering transition and floral development has been extensively examined, their functions in root development remain relatively unexplored. Here, we explored the function and genetic interaction of three MADS-box genes (XAL2, SOC1 and AGL24) in primary root development. Our findings revealed that SOC1 and AGL24, both critical components in flowering transition, redundantly act as repressors of primary root growth as the loss of function of either SOC1 or AGL24 partially recovers the primary root growth, meristem cell number, cell production rate, and the length of fully elongated cells of the short-root mutant xal2-2. Furthermore, we observed that the simultaneous overexpression of AGL24 and SOC1 leads to short-root phenotypes, affecting meristem cell number, cell production rate, fully elongated cell size, but only the overexpression of SOC1 affects distal root stem cell differentiation. Additionally, these genes exhibit distinct modes of transcriptional regulation in roots compared to what has been previously reported for aerial tissues. Moreover, our findings revealed that the expression of certain genes involved in cell differentiation, as well as stress responses, which are either upregulated or downregulated in the xal2-2 mutant, reverted to WT levels in the absence of SOC1 or AGL24.
Project description:Optimised flowering time is an important trait ensuring successful plant adaptation and crop productivity. SOC1-like genes encode MADS transcription factors known to play important roles in flowering control in many plants. This includes the best characterised eudicot model Arabidopsis thaliana (Arabidopsis) where SOC1 promotes flowering and functions as a floral integrator gene integrating signals from different flowering time regulatory pathways. Medicago truncatula (Medicago) is a temperate reference legume with strong genomic and genetic resources used to study flowering pathways in legumes. Interestingly, despite responding to the similar floral-inductive cues of extended cold (vernalisation) followed by warm long days, as winter annual Arabidopsis, Medicago lacks FLC and CO which are key regulators of flowering in Arabidopsis. Unlike Arabidopsis with one SOC1 gene, multiple gene duplication events have given rise to three MtSOC1 paralogs within the Medicago genus in legumes; one Fabaceae group A SOC1 gene, MtSOC1a, and two tandemly-repeated Fabaceae group B SOC1 genes, MtSOC1b and MtSOC1c. Previously, we showed that MtSOC1a has unique functions in floral promotion in Medicago. The Mtsoc1a Tnt1 retroelement insertion single mutant showed moderately delayed flowering in long and short day photoperiods, with and without prior vernalization, compared with wild type. On the other hand, Mtsoc1b Tnt1 single mutants did not have altered flowering time or flower development, indicating that it was redundant in an otherwise wild type background. Here, we describe the generation of Mtsoc1 triple mutant plants by CRISPR-Cas9 gene editing. Two independent Mtsoc1 homozygous triple mutants were non-flowering and bushy in floral inductive VLD. Phenotyping and gene expression analyses by RNA-seq and RT-qPCR indicate that the Mtsoc1 triple mutants remain vegetative. Thus overall, the Mtsoc1 triple mutants are dramatically different from the single Mtsoc1a mutant and the Arabidopsis soc1 mutant; implicating multiple MtSOC1 genes in critical overlapping roles in the transition to flowering in Medicago.
Project description:The mechanisms underlying the precise integration of environmental and developmental signals necessary for plant adaptation to suboptimal environments remain obscure. Here we show that a chromatin switch, mediated by MRG proteins, acts on the floral activator SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1) to coordinate flowering initiation with plant responsiveness to adverse conditions. SOC1 constitutes a central hub in a mechanism that tunes down stress responses likely to optimize plant reproductive success and fitness
Project description:To find downstream target of SOC1, we attemted global expression profiles in gain-of-function mutants of SOC1; To find downstream target of SOC1, we attemted global expression profiles in soc1-101D: ; Expt. 1 GSM73643, GSM73646; Expt. 2 GSM73647, GSM73648; Expt. 3 GSM73649, GSM73650; To find downstream target of SOC1, we attemted global expression profiles in soc1-2: GSM73649, GSM73651; To find downstream target of SOC1, we attemted global expression profiles in gain-of-function mutants of SOC1: ; GSM73643, GSM73646, GSM73647, GSM73648, GSM73649, GSM73650 Experiment Overall Design: To more completely identify the downstream targets of SOC1, we attemted to compare the expression profiles of g-o-f mutant of SOC1 with the results of soc1-2 mutant
Project description:The douple mutant Arabidopsis thaliana soc1 ful, in contrast with WT, produces an interfascicular cambium and a large wood cylinder is the flowering stem. We present the RNAseq data for polyA mRNA of different developmental stages of cambium and wood formation in Arabidopsis thaliana. We sequenced 7 stages; 4 in the woody mutant soc1-6 ful-7 (herbaceous, cambium initiation, wood initiation and leaf) and 3 stages in the WT Col-0 (herbaceous, cambium and leaf). The corresponding stem anatomy is also presented in the manuscript indicating the stage of cambium development and the production of secondary xylem.
Project description:To find downstream target of SOC1, we attemted global expression profiles in gain-of-function mutants of SOC1 To find downstream target of SOC1, we attemted global expression profiles in soc1-101D: Expt. 1 GSM73643, GSM73646 Expt. 2 GSM73647, GSM73648 Expt. 3 GSM73649, GSM73650 To find downstream target of SOC1, we attemted global expression profiles in soc1-2: GSM73649, GSM73651 To find downstream target of SOC1, we attemted global expression profiles in gain-of-function mutants of SOC1: GSM73643, GSM73646, GSM73647, GSM73648, GSM73649, GSM73650 Keywords: genetic modification
Project description:Plants regulate their time to flowering by gathering information from the environment. Photoperiod and temperature are among the most important environmental variables. Suboptimal, but not near-freezing, temperatures regulate flowering through the thermosensory pathway, which overlaps with the autonomous pathway. Here we show that ambient temperature regulates flowering by two genetically distinguishable pathways, one that requires TFL1 and another that requires ELF3. The delay in flowering time observed at lower temperatures was partially suppressed in single elf3 and tfl1 mutants, whereas double elf3 tfl1 mutants were insensitive to temperature. tfl1 mutations abolished the temperature response in cryptochrome mutants that are deficient in photoperiod perception, but not in phyB mutants that have a constitutive photoperiodic response. Contrary to tfl1, elf3 mutations were able to suppress the temperature response in phyB mutants, but not in cryptochrome mutants. The gene expression profile revealed that the tfl1 and elf3 effects are due to the activation of different sets of genes and identified CCA1 and SOC1/AGL20 as being important cross talk points. Finally, genome-wide gene expression analysis strongly suggests a general and complementary role for ELF3 and TFL1 in temperature signalling. Three genotypes, WT (Columbia), elf3-7 and tfl1-1 mutants. Three biological replicates for each condition (genotype X temperature combination). RNA prepared independently for each sample.