scholarly journals Cross-species complementation reveals conserved functions for EARLY FLOWERING 3 between monocots and dicots

2017 ◽  
Author(s):  
He Huang ◽  
Malia A. Gehan ◽  
Sarah E. Huss ◽  
Sophie Alvarez ◽  
Cesar Lizarraga ◽  
...  

ABSTRACTPlant responses to the environment are shaped by external stimuli and internal signaling pathways. In both the model plant Arabidopsis thaliana and crop species, circadian clock factors have been identified as critical for growth, flowering and circadian rhythms. Outside of A. thaliana, however, little is known about the molecular function of clock genes. Therefore, we sought to compare the function of Brachypodium distachyon and Seteria viridis orthologs of EARLY FLOWERING3, a key clock gene in A. thaliana. To identify both cycling genes and putative ELF3 functional orthologs in S. viridis, a circadian RNA-seq dataset and online query tool (Diel Explorer) was generated as a community resource to explore expression profiles of Setaria genes under constant conditions after photo- or thermo-entrainment. The function of ELF3 orthologs from A. thaliana, B. distachyon, and S. viridis were tested for complementation of an elf3 mutation in A. thaliana. Despite comparably low sequence identity versus AtELF3 (less than 37%), both monocot orthologs were capable of rescuing hypocotyl elongation, flowering time and arrhythmic clock phenotypes. Molecular analysis using affinity purification and mass spectrometry to compare physical interactions also found that BdELF3 and SvELF3 could be integrated into similar complexes and networks as AtELF3, including forming a composite evening complex. Thus, we find that, despite 180 million years of separation, BdELF3 and SvELF3 can functionally complement loss of ELF3 at the molecular and physiological level.One Sentence SummaryOrthologs of a key circadian clock component ELF3 from grasses functionally complement the Arabidopsis counterpart at the molecular and physiological level, in spite of high sequence divergence.

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yanlei Yue ◽  
Ze Jiang ◽  
Enoch Sapey ◽  
Tingting Wu ◽  
Shi Sun ◽  
...  

Abstract Background In soybean, some circadian clock genes have been identified as loci for maturity traits. However, the effects of these genes on soybean circadian rhythmicity and their impacts on maturity are unclear. Results We used two geographically, phenotypically and genetically distinct cultivars, conventional juvenile Zhonghuang 24 (with functional J/GmELF3a, a homolog of the circadian clock indispensable component EARLY FLOWERING 3) and long juvenile Huaxia 3 (with dysfunctional j/Gmelf3a) to dissect the soybean circadian clock with time-series transcriptomal RNA-Seq analysis of unifoliate leaves on a day scale. The results showed that several known circadian clock components, including RVE1, GI, LUX and TOC1, phase differently in soybean than in Arabidopsis, demonstrating that the soybean circadian clock is obviously different from the canonical model in Arabidopsis. In contrast to the observation that ELF3 dysfunction results in clock arrhythmia in Arabidopsis, the circadian clock is conserved in soybean regardless of the functional status of J/GmELF3a. Soybean exhibits a circadian rhythmicity in both gene expression and alternative splicing. Genes can be grouped into six clusters, C1-C6, with different expression profiles. Many more genes are grouped into the night clusters (C4-C6) than in the day cluster (C2), showing that night is essential for gene expression and regulation. Moreover, soybean chromosomes are activated with a circadian rhythmicity, indicating that high-order chromosome structure might impact circadian rhythmicity. Interestingly, night time points were clustered in one group, while day time points were separated into two groups, morning and afternoon, demonstrating that morning and afternoon are representative of different environments for soybean growth and development. However, no genes were consistently differentially expressed over different time-points, indicating that it is necessary to perform a circadian rhythmicity analysis to more thoroughly dissect the function of a gene. Moreover, the analysis of the circadian rhythmicity of the GmFT family showed that GmELF3a might phase- and amplitude-modulate the GmFT family to regulate the juvenility and maturity traits of soybean. Conclusions These results and the resultant RNA-seq data should be helpful in understanding the soybean circadian clock and elucidating the connection between the circadian clock and soybean maturity.


2020 ◽  
Author(s):  
P. Lejeune ◽  
A. Fratamico ◽  
F. Bouché ◽  
S. Huerga Fernández ◽  
P. Tocquin ◽  
...  

AbstractCurrent developments in light-emitting diodes (LEDs) technologies have opened new perspectives for sustainable and highly efficient indoor cultivation. The introduction of LEDs not only allows a reduction in the production costs on a quantitative level, it also offers opportunities to manipulate and optimise qualitative traits. Indeed, while plants respond strongest to red and blue lights for photosynthesis, the whole light spectrum has an effect on plant shape, development, and chemical composition. In order to evaluate LEDs as an alternative to traditional lighting sources, the species-specific plant responses to distinct wavelengths need to be evaluated under controlled conditions. Here, we tested the possibility to use light composition gradients in combination with semi-automated phenotyping to rapidly explore the phenotypic responses of different species to variations in the light spectrum provided by LED sources. Plants of seven different species (Arabidopsis thaliana, Ocimum basilicum, Solanum lycopersicum, Brachypodium distachyon, Oryza sativa, Euphorbia peplus, Setaria viridis) were grown under standard white fluorescent light for 30 days, then transferred to a Red:Blue gradient for another 30 days and finally returned to white light. In all species, differences in terms of dimension, shape, and color were rapidly observed across the gradient and the overall response was widely species-dependent. The experiment yielded large amounts of imaging-based phenotypic data and we suggest simple data analysis methods to aggregate the results and facilitate comparisons between species. Similar experimental setups will help achieve rapid environmental optimization, screen new crop species and genotypes, or develop new gene discovery strategies.


2019 ◽  
Author(s):  
Kirk J-M. MacKinnon ◽  
Benjamin J. Cole ◽  
Chang Yu ◽  
Joshua H. Coomey ◽  
Nolan T. Hartwick ◽  
...  

SUMMARYPlants are continuously exposed to diurnal fluctuations in light and temperature, and spontaneous changes in their physical or biotic environment. The circadian clock coordinates regulation of gene expression with a 24-hour period, enabling the anticipation of these events.We used RNA sequencing to characterize the Brachypodium distachyon transcriptome under light and temperature cycles, as well as under constant conditions.Approximately 3% of the transcriptome was regulated by the circadian clock, a smaller proportion reported in most other species. For most transcripts that were rhythmic under all conditions, including many known clock genes, the period of gene expression lengthened from 24 to 27 h in the absence of external cues. To functionally characterize the cyclic transcriptome in B. distachyon, we used Gene Ontology enrichment analysis, and found several terms significantly associated with peak expression at particular times of the day. Furthermore we identified sequence motifs enriched in the promoters of similarly-phased genes, some potentially associated with transcription factors.When considering the overlap in rhythmic gene expression and specific pathway behavior, thermocycles was the prevailing cue that controlled diurnal gene regulation. Taken together, our characterization of the rhythmic B. distachyon transcriptome represents a foundational resource with implications in other grass species.


2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A66-A67
Author(s):  
Audrey L Earnhardt ◽  
David G Riley ◽  
Noushin Ghaffari ◽  
Penny K Riggs ◽  
Charles R Long ◽  
...  

Abstract The primary objective of this investigation was to determine whether circadian clock genes were differentially expressed within or among bovine hypothalamic paraventricular nucleus (PVN), anterior pituitary gland (AP), adrenocortical (AC) and adrenomedullary (AM) tissues. The PVN, AP, AC, and AM were isolated from 5-yr-old Brahman cows (n = 8) harvested humanely at an abattoir between 0800-1100 h. Expression of target genes in each sample was evaluated via RNA-sequencing analyses. Gene counts were normalized using the trimmed mean of M values (TMM) method in the edgeR Package from Bioconductor, R. The normalized gene counts of genes important for circadian rhythm were statistically analyzed using the GLM Procedure of SAS. The genes analyzed were circadian locomotor output cycles protein kaput (CLOCK), cryptochrome circadian regulator 1 and 2 (CRY1 and CRY2), aryl hydrocarbon receptor nuclear translocator like (ARNTL), period circadian regulator 1 and 2 (PER1 and PER2), neuronal PAS domain protein 2 (NPAS2), and nuclear receptor subfamily 1 group D member 1 (NR1D1). Overall, relative expression profiles of clock genes differed (P < 0.01) within each tissue with PER1 having greater expression in all tissues (P < 0.01). Within the PVN expression of CLOCK, CRY1, ARNTL, and PER2 was less than that of CRY2, NPAS2, and NR1D1 (P < 0.01). In the AP, with the exception of PER1, no other clock gene differed in degree of expression. In the AC, expression of CLOCK and NPAS2 was greater than CRY1, ARNTL, PER2, and NR1D1 (P < 0.05), whereas CRY2 expression exceeded only CRY1 (P < 0.05). Within the AM, CLOCK and CRY2 expression was greater than CRY1 and ARNTL (P < 0.05). Overall, clock gene expression among tissues differed (P < 0.01) for each individual clock gene. The AC and AM had similar clock gene expression, except expression of CRY2 and PER2 was greater in AM (P < 0.05). The AC and AM had greater expression of CLOCK than the PVN and AP (P < 0.01), with PVN having greater expression than AP (P < 0.01). The AP had greater expression of NPAS2, followed by PVN, with the least expression in the AC and AM (P < 0.01). Both PVN and AP had greater CRY1 and NR1D1 expression than AC or AM (P < 0.01). The AP had greater PER1 expression than PVN, AC, and AM (P < 0.01), whereas PVN, AC, and AM had greater ARNTL expression than AP (P < 0.05). Both AP and AM had greater expression of PER2 than PVN or AC (P < 0.01). The PVN had greater expression of CRY2 than the AP, AC, and AM (P < 0.01). These results indicated that within each tissue the various clock genes were expressed in different quantities. Also, the clock genes were expressed differentially among the tissues of the bovine neuroendocrine adrenal system. Temporal relationships of these genes with the primary endocrine products of these tissues should be investigated to define the roles of peripheral clock genes in regulation of metabolism and health.


2006 ◽  
Vol 18 (2) ◽  
pp. 167
Author(s):  
T. Amano ◽  
A. Matsushita ◽  
R. Kakegawa ◽  
K. Matsumoto ◽  
K. Saeki ◽  
...  

Matsuo et al. reported that circadian clock genes regulate the timing of cell division in mouse regenerating liver cells (2003). Their results suggested the importance of circadian clock genes for organs or tissues for which functions are characterized by cell division, such as pre-implantation embryos. To obtain basic information on the molecular functions of circadian clock genes in pre-implantation embryos, we investigated the expression profiles of transcripts and proteins of some circadian clock genes, clock, bmal1, cry1, and per2, in mouse germinal vesicle oocytes (GV), MII oocytes (MII), and pre-implantation embryos using real-time PCR and immunocytochemistry (ICC). Germinal vesicle oocytes were collected from ICR females at 48 h after PMSG priming. The mouse at 48 h after PMSG priming was primed with hCG, and MII were collected at 15 h after hCG priming. The pre-implantation embryos were collected at 6, 12, 24, 36, 48, 60, 72, 84, and 96 h after insemination, and they corresponded to early 1-cell, late 1-cell, early 2-cell, late 2-cell, 4-cell, 8-cell, early morula, late morula, and blastocyst stages, respectively. cDNA was produced by mRNA isolated from 20 oocytes or embryos using oligo dT and was subjected to real-time PCR using a TaqMan Probe system (ABI). Three sets of 20 oocytes or embryos at each developmental stage were applied to mRNA extraction and real-time PCR analysis to ensure equal mRNA extraction efficiency between samples. The level of mRNA of each clock gene contained in 3 samples from each developmental stage was almost the same. Statistical analysis of the transcripts of each gene were done by ANOVA. Germinal vesicles, MII and embryos collected at each time point were subjected to ICC using antibodies of CLOCK, BMAL1, CRY1, and PER2. The oocytes or embryos treated with only secondary antibody did not produce any signal. All of the examined genes except per2 were expressed in oocytes and pre-implantation embryos. The transcript level of clock, bmal1, and cry1 in MII were significantly lower than those in GV (P < 0.05). After fertilization, transcript levels of clock, bmal1, and cry1 significantly decreased from early 1-cell stage to late 2-cell stage (P < 0.05). These decreased transcript levels were maintained until the blastocyst stage after the late 2-cell stage. Immunocytochemistry analysis showed the nuclear localization of CLOCK and BMAL1 in early and late 2-cell embryos and of CRY1 in early 2-cell embryos but no signals of PER2 in oocytes or pre-implantation embryos. Because mouse oocytes and 1- to 2-cell embryos are transcriptionally inert, the abundant transcripts of clock, bmal1, and cry1 in these stages seemed to indicate that they were synthesized and stored during the oocyte growth phase. Moreover, the nuclear localization of CLOCK, BMAL1, and CRY1 in the oocytes and 1- to 2-cell stage embryos suggested that some clock genes were translated and worked for oocyte maturation and early embryogenesis. This study was supported by a Grant-in-Aid for the 21st Century COE Program of the Japan Mext and by a grant for the Wakayama Prefecture Collaboration of Regional Entities for the Advancement of Technology Excellence of the JST.


2020 ◽  
Vol 318 (1) ◽  
pp. E1-E10 ◽  
Author(s):  
Laura Sardon Puig ◽  
Nicolas J. Pillon ◽  
Erik Näslund ◽  
Anna Krook ◽  
Juleen R. Zierath

The molecular circadian clock plays a role in metabolic homeostasis. We tested the hypothesis obesity and systemic factors associated with insulin resistance affect skeletal muscle clock gene expression. We determined clock gene expression in skeletal muscle of obese women ( n = 5) and men ( n = 18) before and 6 mo after Roux-en-Y gastric bypass (RYGB) surgery and normal-weight controls (women n = 6, men n = 8). Skeletal muscle clock gene expression was affected by obesity and weight loss. CRY1 mRNA ( P = 0.05) was increased and DBP mRNA ( P < 0.05) was decreased in obese vs. normal weight women and restored to control levels after RYGB-induced weight loss. CLOCK, CRY1, CRY2, and DBP mRNA ( P < 0.05) was decreased in obese men compared with normal weight men. Expression of all other clock genes was unaltered by obesity or weight loss in both cohorts. We correlated clock gene expression with clinical characteristics of the participants. Among the genes studied, DBP and PER3 expression was inversely correlated with plasma lipids in both cohorts. Circadian time-course studies revealed that core clock genes oscillate over time ( P < 0.05), with BMAL1, CIART, CRY2, DBP, PER1, and PER3 expression profiles altered by palmitate treatment. In conclusion, skeletal muscle clock gene expression and function is altered by obesity, coincident with changes in plasma lipid levels. Palmitate exposure disrupts clock gene expression in myotubes, indicating that dyslipidemia directly alters the circadian program. Strategies to reduce lipid overload and prevent elevations in nonesterified fatty acid and cholesterol levels may sustain circadian clock signals in skeletal muscle.


2018 ◽  
Author(s):  
Xueyuan Jiang ◽  
Raquel Assis

AbstractGene duplication has played an important role in the evolution and domestication of flowering plants. Yet little is known about how plant duplicate genes evolve and are retained over long timescales, particularly those arising from small-scale duplication (SSD) rather than whole-genome duplication (WGD) events. Here we address this question in the Poaceae (grass) family by analyzing gene expression data from nine tissues of Brachypodium distachyon, Oryza sativa japonica (rice), and Sorghum bicolor (sorghum). Consistent with theoretical predictions, expression profiles of most grass genes are conserved after SSD, suggesting that functional conservation is the primary outcome of SSD in grasses. However, we also uncover support for widespread functional divergence, much of which occurs asymmetrically via the process of neofunctionalization. Moreover, neofunctionalization preferentially targets younger (child) duplicate gene copies, is associated with RNA-mediated duplication, and occurs quickly after duplication. Further analysis reveals that functional divergence of SSD-derived genes is positively correlated with both sequence divergence and tissue specificity in all three grass species, and particularly with anther expression in B. distachyon. Therefore, as found in many animal species, SSD-derived grass genes often undergo rapid functional divergence that may be driven by natural selection on male-specific phenotypes.


Author(s):  
Soledad Perez Santangelo ◽  
Nathanael Napier ◽  
Fran Robson ◽  
James Weller ◽  
Donna Bond ◽  
...  

Plants use seasonal cues to initiate flowering at an appropriate time of year to ensure optimal reproductive success. The circadian clock integrates these daily and seasonal cues with internal cues to initiate flowering. The molecular pathways that control the sensitivity of flowering to photoperiod (daylength) are well described in the model plant Arabidopsis. However, much less is known in crop species, such as the legume family species. Here we performed a flowering time screen of a TILLING population of Medicago truncatula and found a line with late-flowering and altered light-sensing phenotypes. Using RNA-sequencing, we identified a nonsense mutation in the Phytochromobilin Synthase (MtPΦBS) gene, which encodes an enzyme that carries out the final step in the biosynthesis of the chromophore required for phytochrome (PHY) activity. The analysis of the circadian clock in the MtpΦbs mutant revealed a shorter circadian period, which was shared with the phyA mutant. The MtpΦbs and MtphyA mutants showed downregulation of FT floral regulators MtFTa1, MtFTb1/b2 and a shift in phase for morning and night core clock genes. Our findings show that PHYA is necessary to synchronize the circadian clock and integration of light signaling to promote expression of the MtFT genes to precisely time flowering.


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