Interplay between coding and non-coding regulation drives the Arabidopsis seed-to-seedling transition.
Ontology highlight
ABSTRACT: Translation of seed stored mRNAs is essential to trigger germination. However, when RNAPII re-engages RNA synthesis during the seed-to-seedling transition has remained in question. Combining csRNA-seq, ATAC-seq and smFISH in Arabidopsis thaliana we demonstrate that active transcription initiation is detectable during the entire germination process. Features of non-coding regulation such as dynamic changes in chromatin accessible regions, antisense transcription, as well as bidirectional non-coding promoters are widespread throughout the Arabidopsis genome. We show that sensitivity to exogenous ABSCISIC ACID (ABA) during germination depends on proximal promoter accessibility at ABA-responsive genes. Moreover, we provide genetic validation of the existence of divergent transcription in plants. Our results reveal that active enhancer elements are transcribed producing non-coding enhancer RNAs (eRNAs) as widely documented in metazoans. In sum, this study defining the extent and role of coding and non-coding transcription during key stages of germination expands our understanding of transcriptional mechanisms underlying plant developmental transitions.
Project description:Translation of seed stored mRNAs is essential to trigger germination. However, when RNAPII re-engages RNA synthesis during the seed-to-seedling transition has remained in question. Combining csRNA-seq, ATAC-seq and smFISH in Arabidopsis thaliana we demonstrate that active transcription initiation is detectable during the entire germination process. Features of non-coding regulation such as dynamic changes in chromatin accessible regions, antisense transcription, as well as bidirectional non-coding promoters are widespread throughout the Arabidopsis genome. We show that sensitivity to exogenous ABSCISIC ACID (ABA) during germination depends on proximal promoter accessibility at ABA-responsive genes. Moreover, we provide genetic validation of the existence of divergent transcription in plants. Our results reveal that active enhancer elements are transcribed producing non-coding enhancer RNAs (eRNAs) as widely documented in metazoans. In sum, this study defining the extent and role of coding and non-coding transcription during key stages of germination expands our understanding of transcriptional mechanisms underlying plant developmental transitions.
Project description:Translation of seed stored mRNAs is essential to trigger germination. However, when RNAPII re-engages RNA synthesis during the seed-to-seedling transition has remained in question. Combining csRNA-seq, ATAC-seq and smFISH in Arabidopsis thaliana we demonstrate that active transcription initiation is detectable during the entire germination process. Features of non-coding regulation such as dynamic changes in chromatin accessible regions, antisense transcription, as well as bidirectional non-coding promoters are widespread throughout the Arabidopsis genome. We show that sensitivity to exogenous ABSCISIC ACID (ABA) during germination depends on proximal promoter accessibility at ABA-responsive genes. Moreover, we provide genetic validation of the existence of divergent transcription in plants. Our results reveal that active enhancer elements are transcribed producing non-coding enhancer RNAs (eRNAs) as widely documented in metazoans. In sum, this study defining the extent and role of coding and non-coding transcription during key stages of germination expands our understanding of transcriptional mechanisms underlying plant developmental transitions.
Project description:Translation of seed stored mRNAs is essential to trigger germination. However, when RNAPII re-engages RNA synthesis during the seed-to-seedling transition has remained in question. Combining csRNA-seq, ATAC-seq and smFISH in Arabidopsis thaliana we demonstrate that active transcription initiation is detectable during the entire germination process. Features of non-coding regulation such as dynamic changes in chromatin accessible regions, antisense transcription, as well as bidirectional non-coding promoters are widespread throughout the Arabidopsis genome. We show that sensitivity to exogenous ABSCISIC ACID (ABA) during germination depends on proximal promoter accessibility at ABA-responsive genes. Moreover, we provide genetic validation of the existence of divergent transcription in plants. Our results reveal that active enhancer elements are transcribed producing non-coding enhancer RNAs (eRNAs) as widely documented in metazoans. In sum, this study defining the extent and role of coding and non-coding transcription during key stages of germination expands our understanding of transcriptional mechanisms underlying plant developmental transitions.
Project description:Wheat seed germination directly affects wheat yield and quality. The wheat grains mainly include embryo and endosperm, and both play important roles in seed germination, seedling survival and subsequent vegetative growth. ABA can positively regulate dormancy induction and then negatively regulates seed germination at low concentrations. H2O2 treatment with low concentration can promote seed germination of cereal plants. Although various transcriptomics and proteomics approaches have been used to investigate the seed germination mechanisms and response to various abiotic stresses in different plant species, an integrative transcriptome analysis of wheat embryo and endosperm response to ABA and H2O2 stresses has not reported so far. We used the elite Chinese bread wheat cultivar Zhenmai 9023 as material and performed the first comparative transcriptome microarray analysis between embryo and endosperm response to ABA and H2O2 treatments during seed germination using the GeneChip® Wheat Genome Array Wheat seed germination includes a great amount of regulated genes which belong to many functional groups. ABA/H2O2 can repress/promote seed germination through coordinated regulating related genes expression. Our results provide new insights into the transcriptional regulation mechanisms of embryo and endosperm response to ABA and H2O2 treatments during seed germination
Project description:Wheat seed germination directly affects wheat yield and quality. The wheat grains mainly include embryo and endosperm, and both play important roles in seed germination, seedling survival and subsequent vegetative growth. ABA can positively regulate dormancy induction and then negatively regulates seed germination at low concentrations. H2O2 treatment with low concentration can promote seed germination of cereal plants. Although various transcriptomics and proteomics approaches have been used to investigate the seed germination mechanisms and response to various abiotic stresses in different plant species, an integrative transcriptome analysis of wheat embryo and endosperm response to ABA and H2O2 stresses has not reported so far. We used the elite Chinese bread wheat cultivar Zhenmai 9023 as material and performed the first comparative transcriptome microarray analysis between embryo and endosperm response to ABA and H2O2 treatments during seed germination using the GeneChip® Wheat Genome Array Wheat seed germination includes a great amount of regulated genes which belong to many functional groups. ABA/H2O2 can repress/promote seed germination through coordinated regulating related genes expression. Our results provide new insights into the transcriptional regulation mechanisms of embryo and endosperm response to ABA and H2O2 treatments during seed germination The six groups including embryo and endosperm response to pure water (CK), ABA and H2O2 were havested respectively, which were CK_embryo (CKem), CK_endosperm (CKe), ABA_embryo (ABAem), ABA_endosperm (ABAe), H2O2_embryo (H2O2em), H2O2_endosperm (H2O2e). Three independent experiments were performed for each group.
Project description:The control of seed germination and seed dormancy are critical for the successful propagation of plant species, and are important agricultural traits. Seed germination is tightly controlled by the balance of gibberellin (GA) and abscisic acid (ABA), and is influenced by environmental factors. The COP9 Signalosome (CSN) is a conserved multi-subunit protein complex that is best known as a regulator of the Cullin-RING family of ubiquitin E3 ligases (CRLs). Multiple viable mutants of the CSN showed poor germination, except for csn5b-1. Detailed analyses showed that csn1-10 has a stronger seed dormancy, while csn5a-1 mutants exhibit retarded seed germination in addition to hyperdormancy. Both csn5a-1 and csn1-10 plants show defects in the timely removal of the germination inhibitors: RGL2, a repressor of GA signaling, and ABI5, an effector of ABA responses. We provide genetic evidence to demonstrate that the germination phenotype of csn1-10 is caused by over-accumulation of RGL2, a substrate of the SCF (CRL1) ubiquitin E3 ligase, while the csn5a-1 phenotype is caused by over-accumulation of RGL2 as well as ABI5. The genetic data are consistent with the hypothesis that CSN5A regulates ABI5 by a mechanism that may not involve CSN1. Transcriptome analyses suggest that CSN1 has a more prominent role than CSN5A during seed maturation, but CSN5A plays a more important role than CSN1 during seed germination, further supporting the functional distinction of these two CSN genes. Our study delineates the molecular targets of the CSN complex in seed germination, and reveals that CSN5 has additional functions in regulating ABI5, thus the ABA signaling pathway.
Project description:The mads-box mutant line showed an abscisic acid (ABA)-insensitive phenotype. The AGAMOUS-LIKE 67 (AT1G77950) gene encodes a transcription factor that is nuclear-localized, as observed by transiently transformed epidermal onion cells, specifically expressed in seeds and involved in an ABA signaling pathway during seed germination (Fernández-Arbaizar et al. 2012). SALK_050367 seeds were obtained from the Arabidopsis Biological Resource Center, ABRC.
Project description:Loss of the seed-specific WRKY transcription factor WRKY43 confers enhanced tolerance towards high salt, high osmolarity and low temperature with respect to seed germination. wrky43 loss of function lines display increased inhibition of seed germination in response to exogenous ABA, while WRKY43 overexpression lines are more tolerant towards exogenous ABA. The opposing effect of the wrky43 mutant on salt and ABA tolerance is reminiscent of fatty acid desaturase mutants. Loss of WRKY43 enhances polyunsaturated fatty acid content, particularly 18:2 and 18:3 in TAGs and Phospholipids. Gene chip arrays show that ABA-induced regulation of FUSCA3, ZAT10 and seed storage proteins are absent in the wrky43 mutant. Promoter-Luciferase studies confirm direct regulation of ZAT10 by WRKY43 and suggest indirect regulation of FUS3 and SSPs. In summary WRKY43 acts as a positive regulator of ABA-dependent gene regulation and of fatty acid desaturation that finally results in enhanced tolerance to abiotic stress.
Project description:Seed germination is a critical developmental stage in the life cycle of plants, and its regulation is essential for ensuring crop productivity, particularly under adverse environmental conditions. Here, we find that the Arabidopsis thaliana PRE-MRNA-PROCESSING (PRP21) is crucial for the regulation of abscisic acid (ABA) response of seed germination. Our RNA deep sequencing and poly(A) tag sequencing analyses reveal that PRP21 is involved in pre-mRNA splicing, genome-wide gene transcription, and mRNA 3' end processing, highlighting its multifunctional role in gene regulation. Furthermore, we find that PRP21 interacts with various splicing factors and small nuclear ribonucleoproteins, suggesting its involvement in spliceosome assembly. Additionally, we demonstrate that PRP21 negatively regulates the expression of ABA-responsive genes, such as ABSCISIC ACID-INSENSITIVE 3 (ABI3), ABSCISIC ACID-INSENSITIVE 5 (ABI5), EARLY METHIONINE-LABELED 1 (EM1), and EARLY METHIONINE-LABELED 6 (EM6), thereby modulating ABA response and seed germination. Our findings underscore the importance of PRP21 in coordinating transcriptional and post-transcriptional processes, and provide insights into the molecular mechanisms underlying seed germination, potentially guiding crop improvement for stress tolerance.