Brassinosteroids are steroidal phytohormones that regulate plant development and physiology, including adaptation to environmental stresses. Brassinosteroids are synthesized in the cell interior but bind receptors at the cell surface, necessitating a yet to be identified export mechanism. Here, we show that a member of the ATP-binding cassette (ABC) transporter superfamily, ABCB19, functions as a brassinosteroid exporter. We present its structure in both the substrate-unbound and the brassinosteroid-bound states. Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. In Arabidopsis thaliana, ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses. Our results uncover an elusive export mechanism for bioactive brassinosteroids that is tightly coordinated with brassinosteroid signaling.
- MeSH
- ABC transportéry * chemie genetika metabolismus MeSH
- adenosintrifosfát metabolismus MeSH
- Arabidopsis * genetika metabolismus MeSH
- brassinosteroidy * metabolismus MeSH
- konformace proteinů MeSH
- kyseliny indoloctové metabolismus MeSH
- proteiny huseníčku * chemie genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
The FLOWERING LOCUS T (FT) gene is the essential integrator of flowering regulatory pathways in angiosperms. The paralogs of the FT gene may perform antagonistic functions, as exemplified by BvFT1, that suppresses flowering in Beta vulgaris, unlike the paralogous activator BvFT2. The roles of FT genes in other amaranths were less investigated. Here, we transformed Arabidopsis thaliana with the FLOWERING LOCUS T like (FTL) genes of Chenopodium ficifolium and found that both CfFTL1 and CfFTL2-1 accelerated flowering, despite having been the homologs of the Beta vulgaris floral promoter and suppressor, respectively. The floral promotive effect of CfFTL2-1 was so strong that it caused lethality when overexpressed under the 35S promoter. CfFTL2-1 placed in an inducible cassette accelerated flowering after induction with methoxyphenozide. The spontaneous induction of CfFTL2-1 led to precocious flowering in some primary transformants even without chemical induction. The CqFT2-1 homolog from Chenopodium quinoa had the same impact on viability and flowering as CfFTL2-1 when transferred to A. thaliana. After the FTL gene duplication in Amaranthaceae, the FTL1 copy maintained the role of floral activator. The second copy FTL2 underwent subsequent duplication and functional diversification, which enabled it to control the onset of flowering in amaranths to adapt to variable environments.
- MeSH
- Arabidopsis * genetika metabolismus MeSH
- Chenopodium * genetika metabolismus MeSH
- květy genetika metabolismus MeSH
- proteiny huseníčku * genetika metabolismus MeSH
- regulace genové exprese u rostlin genetika MeSH
- semenáček metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Gene flow between species in the genus Arabidopsis occurs in significant amounts, but how exactly gene flow is achieved is not well understood. Polyploidization may be one avenue to explain gene flow between species. One problem, however, with polyploidization as a satisfying explanation is the occurrence of lethal genomic instabilities in neopolyploids as a result of genomic exchange, erratic meiotic behavior, and genomic shock. We have created an autoallohexaploid by pollinating naturally co-occurring diploid Arabidopsis thaliana with allotetraploid Arabidopsis suecica (an allotetraploid composed of A. thaliana and Arabidopsis arenosa). Its triploid offspring underwent spontaneous genome duplication and was used to generate a multigenerational pedigree. Using genome resequencing, we show that 2 major mechanisms promote stable genomic exchange in this population. Legitimate meiotic recombination and chromosome segregation between the autopolyploid chromosomes of the 2 A. thaliana genomes occur without any obvious bias for the parental origin and combine the A. thaliana haplotypes from the A. thaliana parent with the A. thaliana haplotypes from A. suecica similar to purely autopolyploid plants. In addition, we repeatedly observed that occasional exchanges between regions of the homoeologous chromosomes are tolerated. The combination of these mechanisms may result in gene flow leading to stable introgression in natural populations. Unlike the previously reported resynthesized neoallotetraploid A. suecica, this population of autoallohexaploids contains mostly vigorous, and genetically, cytotypically, and phenotypically variable individuals. We propose that naturally formed autoallohexaploid populations might serve as an intermediate bridge between diploid and polyploid species, which can facilitate gene flow rapidly and efficiently.
The vast majority of agricultural land undergoes abiotic stress that can significantly reduce agricultural yields. Understanding the mechanisms of plant defenses against stresses and putting this knowledge into practice is, therefore, an integral part of sustainable agriculture. In this review, we focus on current findings in plant resistance to four cardinal abiotic stressors-drought, heat, salinity, and low temperatures. Apart from the description of the newly discovered mechanisms of signaling and resistance to abiotic stress, this review also focuses on the importance of primary and secondary metabolites, including carbohydrates, amino acids, phenolics, and phytohormones. A meta-analysis of transcriptomic studies concerning the model plant Arabidopsis demonstrates the long-observed phenomenon that abiotic stressors induce different signals and effects at the level of gene expression, but genes whose regulation is similar under most stressors can still be traced. The analysis further reveals the transcriptional modulation of Golgi-targeted proteins in response to heat stress. Our analysis also highlights several genes that are similarly regulated under all stress conditions. These genes support the central role of phytohormones in the abiotic stress response, and the importance of some of these in plant resistance has not yet been studied. Finally, this review provides information about the response to abiotic stress in major European crop plants-wheat, sugar beet, maize, potatoes, barley, sunflowers, grapes, rapeseed, tomatoes, and apples.
BACKGROUND: The advancement of sequencing technologies today has made a plethora of whole-genome re-sequenced (WGRS) data publicly available. However, research utilizing the WGRS data without further configuration is nearly impossible. To solve this problem, our research group has developed an interactive Allele Catalog Tool to enable researchers to explore the coding region allelic variation present in over 1,000 re-sequenced accessions each for soybean, Arabidopsis, and maize. RESULTS: The Allele Catalog Tool was designed originally with soybean genomic data and resources. The Allele Catalog datasets were generated using our variant calling pipeline (SnakyVC) and the Allele Catalog pipeline (AlleleCatalog). The variant calling pipeline is developed to parallelly process raw sequencing reads to generate the Variant Call Format (VCF) files, and the Allele Catalog pipeline takes VCF files to perform imputations, functional effect predictions, and assemble alleles for each gene to generate curated Allele Catalog datasets. Both pipelines were utilized to generate the data panels (VCF files and Allele Catalog files) in which the accessions of the WGRS datasets were collected from various sources, currently representing over 1,000 diverse accessions for soybean, Arabidopsis, and maize individually. The main features of the Allele Catalog Tool include data query, visualization of results, categorical filtering, and download functions. Queries are performed from user input, and results are a tabular format of summary results by categorical description and genotype results of the alleles for each gene. The categorical information is specific to each species; additionally, available detailed meta-information is provided in modal popups. The genotypic information contains the variant positions, reference or alternate genotypes, the functional effect classes, and the amino-acid changes of each accession. Besides that, the results can also be downloaded for other research purposes. CONCLUSIONS: The Allele Catalog Tool is a web-based tool that currently supports three species: soybean, Arabidopsis, and maize. The Soybean Allele Catalog Tool is hosted on the SoyKB website ( https://soykb.org/SoybeanAlleleCatalogTool/ ), while the Allele Catalog Tool for Arabidopsis and maize is hosted on the KBCommons website ( https://kbcommons.org/system/tools/AlleleCatalogTool/Zmays and https://kbcommons.org/system/tools/AlleleCatalogTool/Athaliana ). Researchers can use this tool to connect variant alleles of genes with meta-information of species.
- MeSH
- alely * MeSH
- Arabidopsis * genetika MeSH
- data mining * metody MeSH
- datové soubory jako téma * MeSH
- frekvence genu MeSH
- genotyp MeSH
- Glycine max * genetika MeSH
- internet * MeSH
- kukuřice setá * genetika MeSH
- metadata MeSH
- mutace MeSH
- pigmentace genetika MeSH
- rostlinné geny genetika MeSH
- software * MeSH
- substituce aminokyselin MeSH
- vegetační klid genetika MeSH
- vizualizace dat MeSH
- Publikační typ
- časopisecké články MeSH
The NGATHA (NGA) transcription factor (TF) belongs to the ABI3/VP1 (RAV) transcriptional subfamily, a subgroup of the B3 superfamily, which is relatively well-studied in Arabidopsis. However, limited data are available on the contributions of NGA TF in other plant species. In this study, 207 NGA gene family members were identified from a genome-wide search against Arabidopsis thaliana in the genome data of 18 dicots and seven monocots. The phylogenetic and sequence alignment analyses divided NGA genes into different clusters and revealed that the numbers of genes varied depending on the species. The phylogeny was followed by the characterization of the Solanaceae (tomato, potato, capsicum, tobacco) and Poaceae (Brachypodium distachyon, Oryza sativa L. japonica, and Sorghum bicolor) family members in comparison with A. thaliana. The gene and protein structures revealed a similar pattern for NGA and NGA-like sequences, suggesting that both are conserved during evolution. Promoter cis-element analysis showed that phytohormones such as abscisic acid, auxin, and gibberellins play a crucial role in regulating the NGA gene family. Gene ontology analysis revealed that the NGA gene family participates in diverse biological processes such as flower development, leaf morphogenesis, and the regulation of transcription. The gene duplication analysis indicates that most of the genes are evolved due to segmental duplications and have undergone purifying selection pressure. Finally, the gene expression analysis implicated that the NGA genes are abundantly expressed in lateral organs and flowers. This analysis has presented a detailed and comprehensive study of the NGA gene family, providing basic knowledge of the gene, protein structure, function, and evolution. These results will lay the foundation for further understanding of the role of the NGA gene family in various plant developmental processes.
- MeSH
- Arabidopsis * genetika metabolismus MeSH
- Brachypodium * genetika MeSH
- fylogeneze MeSH
- genom rostlinný MeSH
- multigenová rodina MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné proteiny genetika metabolismus MeSH
- rýže (rod) * genetika metabolismus MeSH
- transkripční faktory genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
The analysis of dynamic cellular processes such as plant cytokinesis stands and falls with live-cell time-lapse confocal imaging. Conventional approaches to time-lapse imaging of cell division in Arabidopsis root tips are tedious and have low throughput. Here, we describe a protocol for long-term time-lapse simultaneous imaging of multiple root tips on a vertical-stage confocal microscope with automated root tracking. We also provide modifications of the basic protocol to implement this imaging method in the analysis of genetic, pharmacological or laser ablation wounding-mediated experimental manipulations. Our method dramatically improves the efficiency of cell division time-lapse imaging by increasing the throughput, while reducing the person-hour requirements of such experiments.
- MeSH
- Arabidopsis * MeSH
- buněčné dělení MeSH
- časosběrné zobrazování MeSH
- konfokální mikroskopie MeSH
- lidé MeSH
- meristém MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Meiosis in angiosperm plants is followed by mitotic divisions to form multicellular haploid gametophytes. Termination of meiosis and transition to gametophytic development is, in Arabidopsis, governed by a dedicated mechanism that involves SMG7 and TDM1 proteins. Mutants carrying the smg7-6 allele are semi-fertile due to reduced pollen production. We found that instead of forming tetrads, smg7-6 pollen mother cells undergo multiple rounds of chromosome condensation and spindle assembly at the end of meiosis, resembling aberrant attempts to undergo additional meiotic divisions. A suppressor screen uncovered a mutation in centromeric histone H3 (CENH3) that increased fertility and promoted meiotic exit in smg7-6 plants. The mutation led to inefficient splicing of the CENH3 mRNA and a substantial decrease of CENH3, resulting in smaller centromeres. The reduced level of CENH3 delayed formation of the mitotic spindle but did not have an apparent effect on plant growth and development. We suggest that impaired spindle re-assembly at the end of meiosis limits aberrant divisions in smg7-6 plants and promotes formation of tetrads and viable pollen. Furthermore, the mutant with reduced level of CENH3 was very inefficient haploid inducer indicating that differences in centromere size is not the key determinant of centromere-mediated genome elimination.
- MeSH
- aparát dělícího vřeténka MeSH
- Arabidopsis genetika fyziologie MeSH
- fertilita genetika MeSH
- meióza genetika MeSH
- messenger RNA genetika MeSH
- mutace * MeSH
- proteiny huseníčku genetika MeSH
- rostlinné geny * MeSH
- transportní proteiny genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Size control is a fundamental question in biology, showing incremental complexity in plants, whose cells possess a rigid cell wall. The phytohormone auxin is a vital growth regulator with central importance for differential growth control. Our results indicate that auxin-reliant growth programs affect the molecular complexity of xyloglucans, the major type of cell wall hemicellulose in eudicots. Auxin-dependent induction and repression of growth coincide with reduced and enhanced molecular complexity of xyloglucans, respectively. In agreement with a proposed function in growth control, genetic interference with xyloglucan side decorations distinctly modulates auxin-dependent differential growth rates. Our work proposes that auxin-dependent growth programs have a spatially defined effect on xyloglucan's molecular structure, which in turn affects cell wall mechanics and specifies differential, gravitropic hypocotyl growth.
- MeSH
- Arabidopsis fyziologie MeSH
- buněčná stěna metabolismus MeSH
- fluorescenční protilátková technika MeSH
- fyziologie rostlin * MeSH
- glukany chemie metabolismus MeSH
- hrách setý fyziologie MeSH
- kyseliny indoloctové metabolismus MeSH
- regulace genové exprese u rostlin MeSH
- rostlinné buňky metabolismus MeSH
- signální transdukce MeSH
- vývoj rostlin * MeSH
- xylany chemie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Kinesin-like calmodulin-binding protein (KCBP) is a unique kinesin with half kinesin and half myosin, with kinesin motor domain at C-terminus and myosin tail homology region 4 (MyTH4) and band 4.1, ezrin, radixin, moesin (FERM) domains at N-terminus. The special structure endows KCBP multi-intracellular functions, including cell division, trichome morphogenesis in plants, and flagellar function in algae. However, little is known about the molecular mechanism underlying these functions. Here, we identified a molecular chaperone Hsp90 as a novel binding partner with KCBP in Dunaliella salina using a yeast two-hybrid screen. Further analysis showed that Hsp90 interacted with both the N-terminal and C-terminal of DsKCBP. Since Hsp90 was involved in the stability and proteolytic turnover of numerous proteins, whether Hsp90 regulated the degradation of DsKCBP was investigated. Our results showed that both Hsp90 and DsKCBP presented in the purified proteasome, and the interaction of DsKCBP-Hsp90 was inhibited upon Hsp90 inhibitor geldanamycin treatment. The level of DsKCBP proteins was diminished remarkably indicating that the disassociation of DsKCBP from Hsp90 accelerated the degradation of the former. Furthermore, immunofluorescence results showed that the localization of DsKCBP at basal body and flagella was disappeared by Hsp90 inhibition. The increased mRNA level of DsKCBP during flagellar assembly was not obvious by geldanamycin treatment. These data provided evidence that Hsp90 protected DsKCBP from degradation by proteasome and was involved in the role of DsKCBP in flagellar assembly.
