Publications by authors named "Elizabeth Dennis"

163 Publications

Particulated Juvenile Articular Cartilage and Matrix-Induced Autologous Chondrocyte Implantation are Cost-Effective for Patellar Chondral Lesions.

Arthroscopy 2021 Oct 4. Epub 2021 Oct 4.

Purpose: To compare the cost-effectiveness of nonoperative management, particulated juvenile allograft cartilage (PJAC), and matrix-induced autologous chondrocyte implantation (MACI) in the management of patellar chondral lesions.

Methods: A Markov model was utilized to evaluate cost-effectiveness of three strategies for symptomatic patellar chondral lesions: (1) nonoperative management, (2) PJAC, and (3) MACI. Model inputs (transition probabilities, utilities, and costs) were derived from literature review and an institutional cohort of 67 patients treated with PJAC for patellar chondral defects (mean age 26 years, mean lesion size 2.7 cmˆ2). Societal and payer perspectives over a 15-year time horizon were evaluated. The principal outcome measure was the incremental cost-effectiveness ratio (ICER) using a $100,000/quality-adjusted life year (QALY) willingness-to-pay threshold. Sensitivity analyses were performed to assess the robustness of the model and the relative effects of variable estimates on base case conclusions.

Results: From a societal perspective, nonoperative management, PJAC, and MACI cost $4,140, $52,683, and $83,073 and were associated with 5.28, 7.22, and 6.92 QALYs gained, respectively. PJAC and MACI were cost-effective relative to nonoperative management (ICERs $25,010/QALY and $48,344/QALY, respectively). PJAC dominated MACI in the base case analysis by being cheaper and more effective, but this was sensitive to the estimated effectiveness of both strategies. PJAC remained cost-effective if PJAC and MACI were considered equally effective.

Conclusions: In the management of symptomatic patellar cartilage defects, PJAC and MACI were both cost-effective compared to nonoperative management. Due to the need for one surgery instead of two, and less costly graft material, PJAC was cheaper than MACI. Consequently, when PJAC and MACI were considered equally effective, PJAC was more cost-effective than MACI. Sensitivity analyses accounting for the lack of robust long-term data for PJAC or MACI demonstrated that the cost-effectiveness of PJAC versus MACI depended heavily on the relative probabilities of yielding similar clinical results.
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http://dx.doi.org/10.1016/j.arthro.2021.08.038DOI Listing
October 2021

Elbow Varus Torque and Ball Velocity Associations in High School and Professional Pitchers with Increased Sagittal Plane Trunk Tilt.

J Shoulder Elbow Surg 2021 Aug 30. Epub 2021 Aug 30.

Sports Medicine Institute Hospital for Special Surgery, New York, NY, USA. Electronic address:

Background: Increased sagittal plane trunk tilt is thought to increase drive in the anterior direction towards home plate, transferring energy from the trunk to the distal upper extremity, ultimately generating greater ball velocity. Increased sagittal trunk tilt has also been implicated in risk of upper extremity joint loading in baseball pitchers by way of elbow varus torque (EVT), a metric previously associated with elbow injury in professional pitchers.

Purpose: (1) To compare sagittal trunk tilt positioning between high school and professional pitchers throughout the pitch and (2) to identify the potential associations between sagittal plane trunk tilt, ball velocity, and EVT for both cohorts.

Methods: Professional and high school pitchers were instructed to throw fastballs while being evaluated with 3D motion capture (480Hz). Sagittal trunk tilt motion throughout the pitching motion was compared between cohorts from maximum knee height to maximum shoulder internal rotation. To assess the effects of sagittal plane trunk tilt on ball velocity and EVT, linear mixed effect models were created.

Results: Professional pitchers (n=100, pitches: 882) achieved greater sagittal trunk tilt than high school pitchers (n=57, pitches: 519) during early portions of the pitching motion, including maximum positive sagittal trunk tilt (46.6±8.3 vs. 43.6±10.2°, p=0.042). Professional pitchers also had greater sagittal trunk tilt excursion throughout the pitch motion (68.0±11.4 vs. 62.5±11.0°, p=0.004). For every 10° increase in sagittal trunk tilt at ball release (BR) for professional pitchers, ball velocity increased by 0.36 m/s (B= 0.036 and β= 0.194, p<0.001) or 0.9% average ball velocity and EVT increased by 0.14 %BodyWeight(BW)xBodyHeight(BH) (B= 0.014 and β= 0.159, p<0.001) or 2.9% average normalized EVT. For every 10° increase in sagittal trunk tilt at ball release for high school pitchers, ball velocity increased by 0.34m/s (B=0.097 and β=0.025, p=0.025) or 1.1% average ball velocity while EVT increased by 0.07%BWxBH (B=0.007 and β=0.086, p=0.016) or 1.7% average normalized EVT.

Conclusion: Increased positive, sagittal plane trunk tilt was significantly associated with greater ball velocity and increased elbow varus torque for both professional and high school pitchers. Peak elbow varus torque estimates were consistently more pronounced than ball velocity benefits for both populations, suggesting no specific timepoint may provide a ball velocity benefit while concomitantly minimizing elbow varus torque. Both professional and high schooler pitchers should consider this trade-off, which may influence injury risk, when engaging in higher degrees of positive, sagittal plane trunk tilt.
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http://dx.doi.org/10.1016/j.jse.2021.07.028DOI Listing
August 2021

Rice hybrid mimics have stable yields equivalent to those of the F1 hybrid and suggest a basis for hybrid vigour.

Planta 2021 Aug 13;254(3):51. Epub 2021 Aug 13.

State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China.

Main Conclusion: We have developed long term stable high yielding rice lines, Hybrid Mimics, from commercial hybrids. The vigour of the Mimic and the hybrid are developmental changes. These Mimics could substitute for hybrid seed for planting. We have used two pre-existing high-yielding hybrid systems (FLY1 and DY527) to develop Hybrid Mimics. In the FLY1 hybrid system we selected, under field conditions, F6 lines which have high grain yields and biomass equivalent to the F1 hybrids, stable over subsequent F7, F8 and later generations. We have termed these lines Hybrid Mimics. The mimics are mostly homozygous as a consequence of selfing in each generation. We have repeated this selection procedure in the second independent hybrid system DY527, producing Mimics with similar characteristics to the F1 hybrid. In both hybrid systems the selection criterion, based on the phenotype of the F1 hybrid, results in the Mimics having grain yield and biomass similar to that of the F1 hybrid. In each generation of the breeding program the plant population has increased phenotypic homogeneity. The genomes of the Mimic plants do not contain any common heterozygous segments negating claims that the vigour of hybrids depends upon heterozygosity of particular loci. Both hybrids and Mimics have early germination and commence photosynthesis before the parents, providing enhanced growth which is maintained throughout the life cycle. The biochemical parameters of photosynthesis in the hybrids and Mimics do not differ from those of the parents. Grain quality and resistance to the two major diseases, bacterial blight and rice blast are similar in the Mimics and hybrids. The Mimics overcome the major disadvantage of hybrids where F2 phenotypic segregation prevents their use as a crop beyond the F1 generation.
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http://dx.doi.org/10.1007/s00425-021-03700-6DOI Listing
August 2021

Characterization of Histone H3 Lysine 4 and 36 Tri-methylation in L.

Front Plant Sci 2021 7;12:659634. Epub 2021 Jun 7.

Graduate School of Agricultural Science, Kobe University, Kobe, Japan.

Covalent modifications of histone proteins act as epigenetic regulators of gene expression. We report the distribution of two active histone marks (H3K4me3 and H3K36me3) in 14-day leaves in two lines of L. by chromatin immunoprecipitation sequencing. Both lines were enriched with H3K4me3 and H3K36me3 marks at the transcription start site, and the transcription level of a gene was associated with the level of H3K4me3 and H3K36me3. H3K4me3- and H3K36me3-marked genes showed low tissue-specific gene expression, and genes with both H3K4me3 and H3K36me3 had a high level of expression and were constitutively expressed. Bivalent active and repressive histone modifications such as H3K4me3 and H3K27me3 marks or antagonistic coexistence of H3K36me3 and H3K27me3 marks were observed in some genes. Expression may be susceptible to changes by abiotic and biotic stresses in genes having both H3K4me3 and H3K27me3 marks. We showed that the presence of H3K36me3 marks was associated with different gene expression levels or tissue specificity between paralogous paired genes, suggesting that H3K36me3 might be involved in subfunctionalization of the subgenomes.
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http://dx.doi.org/10.3389/fpls.2021.659634DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8215614PMC
June 2021

Development of a New DNA Marker for Fusarium Yellows Resistance in Vegetables.

Plants (Basel) 2021 May 27;10(6). Epub 2021 May 27.

Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan.

In vegetables of L., f. sp. () or f. sp. () cause Fusarium yellows. A resistance gene against () has been identified, and deletion of this gene results in susceptibility (). In contrast, a resistance gene against has not been identified. Inoculation tests showed that lines resistant to were also resistant to , and lines susceptible to were susceptible to . However, prediction of disease resistance by a dominant DNA marker on (Bra012688m) was not associated with disease resistance of in some komatsuna lines using an inoculation test. QTL-seq using four F populations derived from susceptible and resistant lines showed one causative locus on chromosome A03, which covers . Comparison of the amino acid sequence of between susceptible and resistant alleles ( and ) showed that six amino acid differences were specific to susceptible lines. The presence and absence of is consistent with resistance in F populations. These results indicate that is essential for resistance, and changed amino acid sequences result in susceptibility to . This susceptible allele is termed , and a new DNA marker (focbr1-2m) for detection of the allele was developed.
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http://dx.doi.org/10.3390/plants10061082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8229042PMC
May 2021

Genome-wide analysis of long noncoding RNAs, 24-nt siRNAs, DNA methylation and H3K27me3 marks in Brassica rapa.

PLoS One 2021 31;16(3):e0242530. Epub 2021 Mar 31.

Institute of Scientific and Industrial Research, Osaka University, Mihogaoka, Ibaraki-city, Osaka, Japan.

Long noncoding RNAs (lncRNAs) are RNA fragments that generally do not code for a protein but are involved in epigenetic gene regulation. In this study, lncRNAs of Brassica rapa were classified into long intergenic noncoding RNAs, natural antisense RNAs, and intronic noncoding RNAs and their expression analyzed in relation to genome-wide 24-nt small interfering RNAs (siRNAs), DNA methylation, and histone H3 lysine 27 trimethylation marks (H3K27me3). More than 65% of the lncRNAs analyzed consisted of one exon, and more than 55% overlapped with inverted repeat regions (IRRs). Overlap of lncRNAs with IRRs or genomic regions encoding for 24-nt siRNAs resulted in increased DNA methylation levels when both were present. LncRNA did not overlap greatly with H3K27me3 marks, but the expression level of intronic noncoding RNAs that did coincide with H3K27me3 marks was higher than without H3K27me3 marks. The Brassica genus comprises important vegetables and oil seed crops grown across the world. B. rapa is a diploid (AA genome) thought to be one of the ancestral species of both B. juncea (AABB genome) and B. napus (AACC) through genome merging (allotetrapolyploidization). Complex genome restructuring and epigenetic alterations are thought to be involved in these allotetrapolyploidization events. Comparison of lncRNAs between B. rapa and B. nigra, B. oleracea, B. juncea, and B. napus showed the highest conservation with B. oleracea. This study presents a comprehensive analysis of the epigenome structure of B. rapa at multi-epigenetic levels (siRNAs, DNA methylation, H3K27me3, and lncRNAs) and identified a suite of candidate lncRNAs that may be epigenetically regulated in the Brassica genus.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0242530PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8011741PMC
August 2021

Genome Triplication Leads to Transcriptional Divergence of Genes During Vernalization in the Genus .

Front Plant Sci 2020 9;11:619417. Epub 2021 Feb 9.

Graduate School of Agricultural Science, Kobe University, Kobe, Japan.

The genus includes oil crops, vegetables, condiments, fodder crops, and ornamental plants. species underwent a whole genome triplication event after speciation between ancestral species of and closely related genera including . Diploid species such as and have three copies of genes orthologous to each gene, although deletion in one or two of the three homologs has occurred in some genes. The floral transition is one of the crucial events in a plant's life history, and time of flowering is an important agricultural trait. There is a variation in flowering time within species of the genus , and this variation is largely dependent on a difference in vernalization requirements. In , like in , the key gene of vernalization is (). In species, the vernalization response including the repression of expression by cold treatment and the enrichment of the repressive histone modification tri-methylated histone H3 lysine 27 (H3K27me3) at the locus is similar to . and each have four paralogs of , and the allotetraploid species, , has nine paralogs. The increased number of paralogs makes the role of in vernalization more complicated; in a single plant, paralogs vary in the expression level of before and after vernalization. There is also variation in expression levels between accessions. In this review, we focus on the regulatory circuits of the vernalization response of expression in the genus .
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http://dx.doi.org/10.3389/fpls.2020.619417DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7900002PMC
February 2021

The transcriptional response to salicylic acid plays a role in Fusarium yellows resistance in Brassica rapa L.

Plant Cell Rep 2021 Apr 18;40(4):605-619. Epub 2021 Jan 18.

Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe, 657-8501, Japan.

Key Message: Fusarium yellows resistant and susceptible lines in Brassica rapa showed different salicylic acid responses; the resistant line showed a similar response to previous reports, but the susceptible line differed. Fusarium yellows caused by Fusarium oxysporum f. sp. conglutinans (Foc) is an important disease. Previous studies showed that genes related to salicylic acid (SA) response were more highly induced following Foc infection in Brassica rapa Fusarium yellows resistant lines than susceptible lines. However, SA-induced genes have not been identified at the whole genome level and it was unclear whether they were up-regulated by Foc inoculation. Transcriptome analysis with and without SA treatment in the B. rapa Fusarium yellows susceptible line 'Misugi' and the resistant line 'Nanane' was performed to obtain insights into the relationship between SA sensitivity/response and Fusarium yellows resistance. 'Nanane's up-regulated genes were related to SA response and down-regulated genes were related to jasmonic acid (JA) or ethylene (ET) response, but differentially expressed genes in 'Misugi' were not. This result suggests that Fusarium yellows resistant and susceptible lines have a different SA response and that an antagonistic transcription between SA and JA/ET responses was found only in a Fusarium yellows resistant line. SA-responsive genes were induced by Foc inoculation in Fusarium yellows resistant (RJKB-T23) and susceptible lines (RJKB-T24). By contrast, 39 SA-induced genes specific to RJKB-T23 might function in the defense response to Foc. In this study, SA-induced genes were identified at the whole genome level, and the possibility, the defense response to Foc observed in a resistant line could be mediated by SA-induced genes, is suggested. These results will be useful for future research concerning the SA importance in Foc or other diseases resistance in B. rapa.
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http://dx.doi.org/10.1007/s00299-020-02658-1DOI Listing
April 2021

Arabidopsis Col/Ler and Ws/Ler hybrids and Hybrid Mimics produce seed yield heterosis through increased height, inflorescence branch and silique number.

Planta 2020 Aug 26;252(3):40. Epub 2020 Aug 26.

Faculty of Science, University of Technology, Sydney, NSW, 2007, Australia.

Main Conclusion: The seed yield increase of the hybrids and their derived Mimics compared to parents is associated with increased plant height and inflorescence branch number which are correlated with decreased expression of FT, SOC1 and FUL. In Arabidopsis, plant size has been extensively investigated, but few studies have been carried out on seed yield heterosis. In hybrids between Columbia (Col) and Landsberg erecta (Ler), and Wassilewskija (Ws) and Ler, there was significant seed yield heterosis. F6/F7 Hybrid Mimics derived from hybrids of each of the two systems had seed yield increases similar to that of the F1 hybrid (approximately 50-70% greater than the average of the parents). Increased seed yield of the Hybrid Mimics was accompanied by changes of plant architecture with increased plant height and increased inflorescence branch number relative to the parents. Three of the Hybrid Mimic lines derived from the Ws/Ler system had 20% increase in seed yield relative to the F1 hybrid. Genes which repress flowering were up-regulated and the expression levels of flowering -promoting genes including FLOWERING LOCUS T (FT), SUPPRESSOR OF OVEREXPRESSION OF CO 1 (SOC1) and FRUITFULL (FUL) were negatively correlated with the increase in seed yield in both hybrids and F7 Mimics of both systems.
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http://dx.doi.org/10.1007/s00425-020-03444-9DOI Listing
August 2020

Trichomes at the Base of the Petal Are Regulated by the Same Transcription Factors as Cotton Seed Fibers.

Plant Cell Physiol 2020 Sep;61(9):1590-1599

CSIRO Agriculture and Food, Canberra, ACT 2601, Australia.

Many polypetalous plants have a constriction at the base of the petal that leaves a small gap that can provide entry into the young flower bud before the reproductive organs are fully developed. In cotton (Gossypium hirsutum L.), this gap is occluded by tufts of short unicellular trichomes superficially resembling the fibers found on cotton seeds. We are just beginning to understand the developmental regulation of the seed fibers and have previously characterized several MIXTA-like MYB transcription factors (TFs) that are critical for correct seed fiber development but know little about the molecular regulation of other types of cotton trichomes. Here, using RNAi or dominant suppression transgenic cotton lines and natural fiber mutants, we investigated the development and regulation of the petal base trichomes. Petal base trichomes and seed trichomes were also examined across several different species within and outside of the Malvoideae. We found that the petal base trichomes are regulated by the same MYB TFs as cotton seed fibers and, since they are more widely distributed across different taxa than the seed fibers, could have preceded them in the evolution of these important textile fibers produced by some cotton species.
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http://dx.doi.org/10.1093/pcp/pcaa082DOI Listing
September 2020

In Heterosis Level Varies among Individuals in an F Hybrid Population.

Plants (Basel) 2020 Mar 27;9(4). Epub 2020 Mar 27.

Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan.

Heterosis or hybrid vigour is a phenomenon in which hybrid progeny exhibit superior yield and biomass to parental lines and has been used to breed F hybrid cultivars in many crops. A similar level of heterosis in all F individuals is expected as they are genetically identical. However, we found variation in rosette size in individual F plants from a cross between C24 and Columbia-0 accessions of . Big-sized F plants had 26.1% larger leaf area in the first and second leaves than medium-sized F plants at 14 days after sowing in spite of the identical genetic background. We identified differentially expressed genes between big- and medium-sized F plants by microarray; genes involved in the category of stress response were overrepresented. We made transgenic plants overexpressing 21 genes, which were differentially expressed between the two size classes, and some lines had increased plant size at 14 or 21 days after sowing but not at all time points during development. Change of expression levels in stress-responsive genes among individual F plants could generate the variation in plant size of individual F plants in .
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http://dx.doi.org/10.3390/plants9040414DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7238264PMC
March 2020

Early Establishment of Photosynthesis and Auxin Biosynthesis Plays a Key Role in Early Biomass Heterosis in Brassica napus (Canola) Hybrids.

Plant Cell Physiol 2020 Jun;61(6):1134-1143

Agriculture and Food, Commonwealth Scientific and Industrial Research Organization, Canberra, Australian Capital Territory 2600, Australia.

Heterosis or hybrid vigor has been used widely for more than a decade in Canola (Brassica napus) production. Canola hybrids show heterosis in a variety of traits compared to parents, including increased biomass at the early stages of seedling establishment, which is a critical developmental step that impacts future plant growth and seed yield. In this study, we examined transcriptomes of two parental lines, Garnet (Gar) and NX0052 (0052), and their reciprocal hybrids, Gar/0052, at 4 and 8 days after sowing (DAS). In hybrids, early seedling biomass heterosis is correlated with earlier expression of genes in photosynthesis pathways relative to parents. The hybrids also showed early expression of genes in the auxin biosynthesis pathway, consistent with the higher auxin concentrations detected in hybrid seedlings at 4 DAS. Auxin is a key phytohormone that regulates plant development promoting cell expansion and cell proliferation. Consistent with the increased levels of auxin, hybrids have larger and more palisade cells than the parents at the same time point. We propose a possible mechanism of early biomass heterosis through the early establishment of photosynthesis and auxin biosynthesis, providing insights into how transcriptional changes in hybrids are translated into phenotypical heterosis. This finding could be utilized in future Canola breeding to identify hybrid combinations with the superior early seedling establishment and strong levels of hybrid vigor in later plant development.
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http://dx.doi.org/10.1093/pcp/pcaa038DOI Listing
June 2020

Leaf growth in early development is key to biomass heterosis in Arabidopsis.

J Exp Bot 2020 04;71(8):2439-2450

Agriculture and Food, Commonwealth Scientific and Industry Research Organisation, Canberra, ACT, Australia.

Arabidopsis thaliana hybrids have similar properties to hybrid crops, with greater biomass relative to the parents. We asked whether the greater biomass was due to increased photosynthetic efficiency per unit leaf area or to overall increased leaf area and increased total photosynthate per plant. We found that photosynthetic parameters (electron transport rate, CO2 assimilation rate, chlorophyll content, and chloroplast number) were unchanged on a leaf unit area and unit fresh weight basis between parents and hybrids, indicating that heterosis is not a result of increased photosynthetic efficiency. To investigate the possibility of increased leaf area producing more photosynthate per plant, we studied C24×Landsberg erecta (Ler) hybrids in detail. These hybrids have earlier germination and leaf growth than the parents, leading to a larger leaf area at any point in development of the plant. The developing leaves of the hybrids are significantly larger than those of the parents, with consequent greater production of photosynthate and an increased contribution to heterosis. The set of leaves contributing to heterosis changes as the plant develops; the four most recently emerged leaves make the greatest contribution. As a leaf matures, its contribution to heterosis attenuates. While photosynthesis per unit leaf area is unchanged at any stage of development in the hybrid, leaf area is greater and the amount of photosynthate per plant is increased.
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http://dx.doi.org/10.1093/jxb/eraa006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7178430PMC
April 2020

In Arabidopsis hybrids and Hybrid Mimics, up-regulation of cell wall biogenesis is associated with the increased plant size.

Plant Direct 2019 Nov 6;3(11):e00174. Epub 2019 Nov 6.

Faculty of Science University of Technology Sydney NSW Australia.

Hybrid breeding is of economic importance in agriculture for increasing yield, yet the basis of heterosis is not well understood. In Arabidopsis, crosses between different accessions produce hybrids with different levels of heterosis relative to parental phenotypes in biomass. In all hybrids, the advantage of the F1 hybrid in both phenotypic uniformity and yield gain is lost in the heterogeneous F2. F5/F6 Hybrid Mimics generated from a cross between C24 and Landsberg (L) ecotypes demonstrated that the large plant phenotype of the F1 hybrids can be stabilized. Hybrid Mimic selection was applied to Wassilewskija (Ws)/L and Col/L hybrids. The two hybrids show different levels of heterosis. The Col/L hybrid generated F7 Hybrid Mimics with rosette diameter and fresh weight equivalent to the F1 hybrid at 30 DAS; F7 Ws/L Hybrid Mimics outperformed the F1 hybrid in both the rosette size and biomass. Transcriptome analysis revealed up-regulation of cell wall biosynthesis, and cell wall expansion genes could be a common pathway in increased size in the Arabidopsis hybrids and Hybrid Mimics. Intercross of two independent Hybrid Mimic lines can further increase the biomass gain. Our results encourage the use of Hybrid Mimics for breeding and for investigating the molecular basis of heterosis.
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http://dx.doi.org/10.1002/pld3.174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6834268PMC
November 2019

The histone modification H3 lysine 27 tri-methylation has conserved gene regulatory roles in the triplicated genome of Brassica rapa L.

DNA Res 2019 Oct;26(5):433-443

Graduate School of Agricultural Science, Kobe University, Kobe, Japan.

Brassica rapa L. is an important vegetable and oilseed crop. We investigated the distribution of the histone mark tri-methylation of H3K27 (H3K27me3) in B. rapa and its role in the control of gene expression at two stages of development (2-day cotyledons and 14-day leaves) and among paralogs in the triplicated genome. H3K27me3 has a similar distribution in two inbred lines, while there was variation of H3K27me3 sites between tissues. Sites that are specific to 2-day cotyledons have increased transcriptional activity, and low levels of H3K27me3 in the gene body region. In 14-day leaves, levels of H3K27me3 were associated with decreased gene expression. In the triplicated genome, H3K27me3 is associated with paralogs that have tissue-specific expression. Even though B. rapa and Arabidopsis thaliana are not closely related within the Brassicaceae, there is conservation of H3K27me3-marked sites in the two species. Both B. rapa and A. thaliana require vernalization for floral initiation with FLC being the major controlling locus. In all four BrFLC paralogs, low-temperature treatment increases H3K27me3 at the proximal nucleation site reducing BrFLC expression. Following return to normal temperature growth conditions, H3K27me3 spreads along all four BrFLC paralogs providing stable repression of the gene.
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http://dx.doi.org/10.1093/dnares/dsz021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6796510PMC
October 2019

The role of FRIGIDA and FLOWERING LOCUS C genes in flowering time of Brassica rapa leafy vegetables.

Sci Rep 2019 09 25;9(1):13843. Epub 2019 Sep 25.

Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe, 657-8501, Japan.

There is a wide variation of flowering time among lines of Brassica rapa L. Most B. rapa leafy (Chinese cabbage etc.) or root (turnip) vegetables require prolonged cold exposure for flowering, known as vernalization. Premature bolting caused by low temperature leads to a reduction in the yield/quality of these B. rapa vegetables. Therefore, high bolting resistance is an important breeding trait, and understanding the molecular mechanism of vernalization is necessary to achieve this goal. In this study, we demonstrated that BrFRIb functions as an activator of BrFLC in B. rapa. We showed a positive correlation between the steady state expression levels of the sum of the BrFLC paralogs and the days to flowering after four weeks of cold treatment, suggesting that this is an indicator of the vernalization requirement. We indicate that BrFLCs are repressed by the accumulation of H3K27me3 and that the spreading of H3K27me3 promotes stable FLC repression. However, there was no clear relationship between the level of H3K27me3 in the BrFLC and the vernalization requirement. We also showed that if there was a high vernalization requirement, the rate of repression of BrFLC1 expression following prolonged cold treatments was lower.
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http://dx.doi.org/10.1038/s41598-019-50122-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6761103PMC
September 2019

Long noncoding RNAs in Brassica rapa L. following vernalization.

Sci Rep 2019 06 26;9(1):9302. Epub 2019 Jun 26.

Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe, 657-8501, Japan.

Brassica rapa L. is an important agricultural crop that requires a period of prolonged cold for flowering. This process is known as vernalization. Studies have shown that long noncoding RNAs (lncRNAs) play important roles in abiotic stress responses and several cold-responsive noncoding RNAs have been suggested to be involved in vernalization. We examined the transcriptome of the Chinese cabbage inbred line (B. rapa L. var. pekinensis) RJKB-T24, and identified 1,444 long intergenic noncoding RNAs (lincRNAs), 551 natural antisense transcripts (NATs), and 93 intronic noncoding RNAs (incRNAs); 549 of the 2,088 lncRNAs significantly altered their expression in response to four weeks of cold treatment. Most differentially expressed lncRNAs did not lead to a change of expression levels in mRNAs covering or near lncRNAs, suggesting that the transcriptional responses to four weeks of cold treatment in lncRNA and mRNA are independent. However, some differentially expressed mRNAs had NATs with expression altered in the same direction. These genes were categorized as having an abiotic stress response, suggesting that the paired-expression may play a role in the transcriptional response to vernalization or cold treatment. We also identified short-term cold treatment induced NATs in BrFLC and BrMAF genes, which are involved in vernalization. The lncRNAs we identified differed from those reported in Arabidopsis thaliana, suggesting the role of lncRNAs in vernalization differ between these two species.
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http://dx.doi.org/10.1038/s41598-019-45650-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6594933PMC
June 2019

plays a role in DNA demethylation and disease response in somatic tissues of Arabidopsis.

Epigenetics 2019 11 19;14(11):1074-1087. Epub 2019 Jun 19.

CSIRO Agriculture and Food , Acton , Australia.

DNA demethylases function in conjunction with DNA methyltransferases to modulate genomic DNA methylation levels in plants. The Arabidopsis genome contains four DNA demethylase genes, ( () also known as ( and . While and were shown to function in disease response in somatic tissues, has been thought to function only in reproductive tissues to maintain the maternal-specific expression pattern of a subset of imprinted genes. Here we used promoter:β-glucuronidase (GUS) fusion constructs to show that is constitutively expressed throughout the plant, and that and have tissue-specific expression patterns. Loss-of-function mutations in cause seed abortion and therefore viable mutants are not available for gene function analysis. We knocked down expression in a triple () mutant background using green tissue-specific expression of a hairpin RNA transgene (RNAi), generating a viable 'quadruple' demethylase mutant line. We show that this RNAi line has enhanced disease susceptibility to infection compared to the triple mutant. Furthermore, several defence-related genes, previously shown to be repressed in , were further repressed in the RNAi plants. DNA methylation analysis of two of these genes revealed increased differential promoter DNA methylation in RNAi plants compared to WT, beyond the difference observed in the parental plants. These results indicate that contributes to DNA demethylase activity and disease response in somatic tissues.
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http://dx.doi.org/10.1080/15592294.2019.1631113DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6773409PMC
November 2019

Ankle Injuries in Dancers.

J Am Acad Orthop Surg 2019 Aug;27(16):582-589

From the Department of Orthopaedic Surgery (Dr. Vosseller and Dr. Dennis), Columbia University Medical Center, and The ADAM Center (Dr. Bronner), The Alvin Ailey American Dance Theater, New York city, NY.

The term dance encompasses a broad range of different styles; much of the orthopaedic literature has focused on ballet dancers. Injury is common in dancers at all levels, and many serious dancers sustain multiple injuries as they progress through their career. Foot and ankle injuries are among the most common injuries experienced by dancers. These injuries include those that are specific to dancers because of the unique physical maneuvers required to effectively perform, but they can also include common injuries that may require relatively different treatment because of the physical demands of the dancer. Os trigonum syndrome and flexor hallucis longus tenosynovitis generally fall into the former category as they are injuries that are more prevalent in dancers due to the extreme plantarflexion involved in dancing, especially ballet, and the relative demand placed on the toe flexors, most notably the flexor hallucis longus. On the other hand, anterior ankle impingement occurs both in dancers and in the general public. In many cases, a team approach to treatment with knowledgeable physical therapists can obviate the need for surgical treatment. If surgical treatment proves necessary, good results can be achieved with sound surgical technique and a well thought-out rehabilitation program.
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http://dx.doi.org/10.5435/JAAOS-D-18-00596DOI Listing
August 2019

Senescence and Defense Pathways Contribute to Heterosis.

Plant Physiol 2019 05 1;180(1):240-252. Epub 2019 Feb 1.

CSIRO Agriculture and Food, Canberra, Australian Capital Territory 2601, Australia

Hybrids are used extensively in agriculture due to their superior performance in seed yield and plant growth, yet the molecular mechanisms underpinning hybrid performance are not well understood. Recent evidence has suggested that a decrease in basal defense response gene expression regulated by reduced levels of salicylic acid (SA) may be important for vigor in certain hybrid combinations. Decreasing levels of SA in the Arabidopsis () accession C24 through the introduction of the SA catabolic enzyme salicylate1 hydroxylase (NahG) increases plant size, phenocopying the large-sized C24/Landsberg (L) F1 hybrids. C24♀ × L♂ F1 hybrids and C24 NahG lines shared differentially expressed genes and pathways associated with plant defense and leaf senescence including decreased expression of SA biosynthetic genes and SA response genes. The expression of , a key regulator in resource allocation between growth and defense, was decreased in both the F1 hybrid and the C24 NahG lines, which may promote growth. Both C24 NahG lines and the F1 hybrids showed decreased expression of the key senescence-associated transcription factors , -, and with a delayed onset of senescence compared to C24 plants. The delay in senescence resulted in an extension of the photosynthetic period in the leaves of F1 hybrids compared to the parental lines, potentially allowing each leaf to contribute more resources toward growth.
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http://dx.doi.org/10.1104/pp.18.01205DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6501064PMC
May 2019

Treatment of Adhesive Capsulitis of the Shoulder.

J Am Acad Orthop Surg 2019 Jun;27(12):e544-e554

From the Columbia University Medical Center, Department of Orthopedics, Center for Shoulder Elbow and Sports Medicine, New York, NY.

Adhesive capsulitis presents clinically as limited, active and passive range of motion caused by the formation of adhesions of the glenohumeral joint capsule. Radiographically, it is thickening of the capsule and rotator interval. The pathology of the disease, and its classification, relates to inflammation and formation of extensive scar tissue. Risk factors include diabetes, hyperthyroidism, and previous cervical spine surgery. Nonsurgical management includes physical therapy, corticosteroid injections, extracorporeal shock wave therapy, calcitonin, ultrasonography-guided hydrodissection, and hyaluronic acid injections. Most patients will see complete resolution of symptoms with nonsurgical management, and there appears to be a role of early corticosteroid injection in shortening the overall duration of symptoms. Surgical intervention, including manipulation under anesthesia, arthroscopic capsular release both limited and circumferential, and the authors' technique are described in this article. Complications include fracture, glenoid and labral injuries, neurapraxia, and rotator cuff pathology. Postoperative care should always include early physical therapy.
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http://dx.doi.org/10.5435/JAAOS-D-17-00606DOI Listing
June 2019

Cotyledons contribute to plant growth and hybrid vigor in Arabidopsis.

Planta 2019 Apr 14;249(4):1107-1118. Epub 2018 Dec 14.

Faculty of Science, University of Technology, Sydney, NSW, 2007, Australia.

Main Conclusion: In hybrids of Arabidopsis, cotyledons influence the amount and proportion of hybrid vigor in total plant growth. We found Arabidopsis cotyledons are essential for plant growth and in some hybrids for hybrid vigor. In hybrids between C24 and Landsberg erecta (Ler), biomass vigor (heterosis) occurs in the first few days after sowing (DAS), with hybrid cotyledons being larger than those of their parents. C24xLer hybrids are ahead of their parents in activating photosynthesis and auxin pathway genes in cotyledons at 3-4 DAS. "Earliness" is also present in newly emerged C24xLer hybrid leaves. We showed cotyledon removal at 4 DAS caused significant biomass reduction in later growth in hybrids and parental lines. The biomass decrease caused by cotyledon removal can be partially rescued by exogenous sucrose or auxin with different genotypes responding to sucrose and/or auxin differently. Cotyledon removal has different effects on heterosis in different hybrids. After cotyledon removal, in C24xLer hybrids, both growth and heterosis were reduced in similar proportions, but the level of hybrid vigor was reduced as a proportion of growth in C24xColumbia (Col) and ColxLer hybrids. The removal of cotyledons at 4 DAS markedly decreased the level of growth and eliminated the heterotic phenotype of Wassilewskija (Ws)/Ler hybrids. In mutant Ws/Ler hybrids which had a reduced level of photosynthesis in the cotyledons, there was a reduction in plant growth and loss of heterosis. The variation in contribution of cotyledons to heterosis in different hybrids indicates there are multiple pathways to achieve heterotic phenotypes.
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http://dx.doi.org/10.1007/s00425-018-3068-6DOI Listing
April 2019

Genome-wide characterization of DNA methylation, small RNA expression, and histone H3 lysine nine di-methylation in Brassica rapa L.

DNA Res 2018 Oct;25(5):511-520

Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe, Japan.

Epigenetic gene regulation is crucial to plant life and can involve dynamic interactions between various histone modifications, DNA methylation, and small RNAs. Detailed analysis of epigenome information is anticipated to reveal how the DNA sequence of the genome is translated into the plant's phenotype. The aim of this study was to map the DNA methylation state at the whole genome level and to clarify the relationship between DNA methylation and transcription, small RNA expression, and histone H3 lysine 9 di-methylation (H3K9me2) in Brassica rapa. We performed whole genome bisulfite sequencing, small RNA sequencing, and chromatin immunoprecipitation sequencing using H3K9me2 antibody in a Chinese cabbage inbred line, RJKB-T24, and examined the impact of epigenetic states on transcription. Cytosine methylation in DNA was analysed in different sequence contexts (CG, CHG, and CHH) (where H could be A, C, or T) and position (promoter, exon, intron, terminator, interspersed repeat regions), and the H3K9me2 and 24 nucleotide small interfering RNAs (24 nt-siRNA) were overlaid onto the B. rapa reference genome. The epigenome was compared with that of Arabidopsis thaliana and the relationship between the position of DNA methylation and gene expression, and the involvement of 24 nt siRNAs and H3K9me2 are discussed.
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http://dx.doi.org/10.1093/dnares/dsy021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6191303PMC
October 2018

Recent research on the mechanism of heterosis is important for crop and vegetable breeding systems.

Breed Sci 2018 Mar 12;68(2):145-158. Epub 2018 Apr 12.

CSIRO Agriculture and Food, Canberra, ACT 2601, Australia.

Heterosis or hybrid vigor is a phenomenon where hybrid progeny have superior performance compared to their parental inbred lines. This is important in the use of F hybrid cultivars in many crops and vegetables. However, the molecular mechanism of heterosis is not clearly understood. Gene interactions between the two genomes such as dominance, overdominance, and epistasis have been suggested to explain the increased biomass and yield. Genetic analyses of F hybrids in maize, rice, and canola have defined a large number of quantitative trait loci, which may contribute to heterosis. Recent molecular analyses of transcriptomes together with reference to the epigenome of the parents and hybrids have begun to uncover new facts about the generation of heterosis. These include the identification of gene expression changes in hybrids, which may be important for heterosis, the role of epigenetic processes in heterosis, and the development of stable high yielding lines.
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http://dx.doi.org/10.1270/jsbbs.17155DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5982191PMC
March 2018

Determining glenoid component version after total shoulder arthroplasty.

J Shoulder Elbow Surg 2018 Sep 11;27(9):1588-1595. Epub 2018 May 11.

Department of Orthopaedic Surgery, Columbia University Medical Center, New York, NY, USA. Electronic address:

Background: Glenoid component loosening after total shoulder arthroplasty (TSA) may occur if retroversion is not corrected to <10°. However, accurately measuring postoperative glenoid component version has been difficult without postoperative computed tomography (CT), adding cost and radiation exposure outside of the standard radiographic follow-up. We present a new method to assess glenoid component version after TSA using only routine preoperative CT and postoperative radiographs (x-rays).

Methods: Preoperative glenoid version was measured using established methods with an axillary x-ray, 2-dimensional CT, and Glenosys software (Imascap, Plouzané, France). Postoperative glenoid component version and inclination were measured for 61 TSA patients using Mimics software (Materialise, Leuven, Belgium) with preoperative CT and postoperative x-rays. Four patients also had postoperative CTs. Glenoid implantation and imaging were performed on 14 cadavers, allowing validation of results against the gold standard postoperative CT glenoid retroversion measurement.

Results: Compared with the gold standard, retroversion and inclination measurement error was 2° ± 1° and 2° ± 1°, respectively. Average postoperative version correction was 6° ± 7°, with 35 of 61 patients (57%) corrected to <10° of retroversion. Correlation between preoperative version measurement methods was good to very good, except on the axillary x-ray. Patients not corrected to <10° of retroversion had significantly higher preoperative retroversion (14° ± 6°) than those corrected to <10° (6° ± 7°; P < .00001).

Conclusions: Glenoid component retroversion after TSA can be accurately measured with a method using only routine preoperative CT and postoperative x-rays, validated to within 1.9° of the gold standard postoperative CT measurement. Future studies using this method may correlate glenoid retroversion correction with glenoid component longevity to help optimize shoulder arthroplasty outcomes.
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http://dx.doi.org/10.1016/j.jse.2018.03.003DOI Listing
September 2018

Correction to: Tissue and cell-specific transcriptomes in cotton reveal the subtleties of gene regulation underlying the diversity of plant secondary cell walls.

BMC Genomics 2018 04 17;19(1):261. Epub 2018 Apr 17.

CSIRO Agriculture and Food, PO Box 1700, Canberra, ACT 2601, Australia.

Upon publication of the original article [1], the authors had flagged that Fig. 1 had been published twice, as both Fig. 1 and Additional file 3.
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http://dx.doi.org/10.1186/s12864-018-4634-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5902885PMC
April 2018

Anisometry of Medial Patellofemoral Ligament Reconstruction in the Setting of Increased Tibial Tubercle-Trochlear Groove Distance and Patella Alta.

Arthroscopy 2018 02;34(2):502-510

Sports Medicine and Shoulder Service, Hospital for Special Surgery, New York, New York; Department of Orthopedic Surgery, Weill Cornell Medical College, New York, New York.

Purpose: To assess the impact elevated tibial tubercle-trochlear groove (TT-TG) distance and patella height, as measured by the Caton-Deschamps Index (CDI), have on the isometry of a reconstructed medial patellofemoral ligament (MPFL).

Methods: Nine fresh-frozen cadaveric knees were placed on a custom testing fixture, with a fixed femur and a mobile tibia. A suture fixed to the MPFL origin on the patella and free to move at the Schöttle point on the femur represented a reconstructed MPFL. A local coordinate system was established, and retroreflective markers attached to the suture quantified MPFL length changes by use of a 3-dimensional motion capture system. The tubercle was transferred to create TT-TG distances of 20 mm and 25 mm and CDIs of 1.2 and 1.4 (patella alta). Recordings of the MPFL suture length change as the knee was brought through a range of motion were made using all combinations of tubercle anatomy in a randomized order for each specimen. A generalized estimating equation modeling technique was used to analyze and control for the clustered nature of the data.

Results: Knees with native tibial tubercle anatomy showed MPFL isometry through 20° to 70° range of motion. Tibial tubercle lateralization (increased TT-TG distance) significantly altered MPFL isometry with a TT-TG distance of 20 mm (P < .0001). Patella alta significantly altered MPFL isometry with a CDI of 1.2 (P = .0182). The interaction of tibial tubercle lateralization combined with patella alta significantly increased the amount of anisometry seen in the reconstructed MPFL (P < .001).

Conclusions: Increased tibial tubercle lateralization and patella alta produce anisometry in an MPFL reconstruction using currently recommended landmarks, leading to potentially increased graft tension and potential failure.

Clinical Relevance: Tibial tubercle transfer should be considered when performing an MPFL reconstruction for recurrent patellofemoral instability in the setting of significant patella alta and an elevated TT-TG distance-especially when both are present-because an isolated MPFL reconstruction will be prone to failure given the anisometry shown in this study.
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http://dx.doi.org/10.1016/j.arthro.2017.08.256DOI Listing
February 2018

Comparison of transcriptome profiles by Fusarium oxysporum inoculation between Fusarium yellows resistant and susceptible lines in Brassica rapa L.

Plant Cell Rep 2017 Dec 17;36(12):1841-1854. Epub 2017 Aug 17.

Graduate School of Science and Technology, Niigata University, Ikarashi-ninocho, Niigata, 950-2181, Japan.

Key Message: Resistant and susceptible lines in Brassica rapa have different immune responses against Fusarium oxysporum inoculation. Fusarium yellows caused by Fusarium oxysporum f. sp. conglutinans (Foc) is an important disease of Brassicaceae; however, the mechanism of how host plants respond to Foc is still unknown. By comparing with and without Foc inoculation in both resistant and susceptible lines of Chinese cabbage (Brassica rapa var. pekinensis), we identified differentially expressed genes (DEGs) between the bulked inoculated (6, 12, 24, and 72 h after inoculation (HAI)) and non-inoculated samples. Most of the DEGs were up-regulated by Foc inoculation. Quantitative real-time RT-PCR showed that most up-regulated genes increased their expression levels from 24 HAI. An independent transcriptome analysis at 24 and 72 HAI was performed in resistant and susceptible lines. GO analysis using up-regulated genes at 24 HAI indicated that Foc inoculation activated systemic acquired resistance (SAR) in resistant lines and tryptophan biosynthetic process and responses to chitin and ethylene in susceptible lines. By contrast, GO analysis using up-regulated genes at 72 HAI showed the overrepresentation of some categories for the defense response in susceptible lines but not in the resistant lines. We also compared DEGs between B. rapa and Arabidopsis thaliana after F. oxysporum inoculation at the same time point, and identified genes related to defense response that were up-regulated in the resistant lines of Chinese cabbage and A. thaliana. Particular genes that changed expression levels overlapped between the two species, suggesting that they are candidates for genes involved in the resistance mechanisms against F. oxysporum.
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http://dx.doi.org/10.1007/s00299-017-2198-9DOI Listing
December 2017

Analysis of Argonaute 4-Associated Long Non-Coding RNA in Arabidopsis thaliana Sheds Novel Insights into Gene Regulation through RNA-Directed DNA Methylation.

Genes (Basel) 2017 Aug 7;8(8). Epub 2017 Aug 7.

Commonwealth Scientific and Industrial Research Organisation Agriculture, Canberra, Australian Capital Territory 2601, Australia.

RNA-directed DNA methylation (RdDM) is a plant-specific de novo DNA methylation mechanism that requires long noncoding RNA (lncRNA) as scaffold to define target genomic loci. While the role of RdDM in maintaining genome stability is well established, how it regulates protein-coding genes remains poorly understood and few RdDM target genes have been identified. In this study, we obtained sequences of RdDM-associated lncRNAs using nuclear RNA immunoprecipitation against ARGONAUTE 4 (AGO4), a key component of RdDM that binds specifically with the lncRNA. Comparison of these lncRNAs with gene expression data of RdDM mutants identified novel RdDM target genes. Surprisingly, a large proportion of these target genes were repressed in RdDM mutants suggesting that they are normally activated by RdDM. These RdDM-activated genes are more enriched for gene body lncRNA than the RdDM-repressed genes. Histone modification and RNA analyses of several RdDM-activated stress response genes detected increased levels of active histone mark and short RNA transcript in the lncRNA-overlapping gene body regions in the mutant despite the repressed expression of these genes. These results suggest that RdDM, or AGO4, may play a role in maintaining or activating stress response gene expression by directing gene body chromatin modification preventing cryptic transcription.
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http://dx.doi.org/10.3390/genes8080198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5575662PMC
August 2017

Tissue and cell-specific transcriptomes in cotton reveal the subtleties of gene regulation underlying the diversity of plant secondary cell walls.

BMC Genomics 2017 07 18;18(1):539. Epub 2017 Jul 18.

CSIRO Agriculture and Food, PO Box 1700, Canberra, ACT, 2601, Australia.

Background: Knowledge of plant secondary cell wall (SCW) regulation and deposition is mainly based on the Arabidopsis model of a 'typical' lignocellulosic SCW. However, SCWs in other plants can vary from this. The SCW of mature cotton seed fibres is highly cellulosic and lacks lignification whereas xylem SCWs are lignocellulosic. We used cotton as a model to study different SCWs and the expression of the genes involved in their formation via RNA deep sequencing and chemical analysis of stem and seed fibre.

Results: Transcriptome comparisons from cotton xylem and pith as well as from a developmental series of seed fibres revealed tissue-specific and developmentally regulated expression of several NAC transcription factors some of which are likely to be important as top tier regulators of SCW formation in xylem and/or seed fibre. A so far undescribed hierarchy was identified between the top tier NAC transcription factors SND1-like and NST1/2 in cotton. Key SCW MYB transcription factors, homologs of Arabidopsis MYB46/83, were practically absent in cotton stem xylem. Lack of expression of other lignin-specific MYBs in seed fibre relative to xylem could account for the lack of lignin deposition in seed fibre. Expression of a MYB103 homolog correlated with temporal expression of SCW CesAs and cellulose synthesis in seed fibres. FLAs were highly expressed and may be important structural components of seed fibre SCWs. Finally, we made the unexpected observation that cell walls in the pith of cotton stems contained lignin and had a higher S:G ratio than in xylem, despite that tissue's lacking many of the gene transcripts normally associated with lignin biosynthesis.

Conclusions: Our study in cotton confirmed some features of the currently accepted gene regulatory cascade for 'typical' plant SCWs, but also revealed substantial differences, especially with key downstream NACs and MYBs. The lignocellulosic SCW of cotton xylem appears to be achieved differently from that in Arabidopsis. Pith cell walls in cotton stems are compositionally very different from that reported for other plant species, including Arabidopsis. The current definition of a 'typical' primary or secondary cell wall might not be applicable to all cell types in all plant species.
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http://dx.doi.org/10.1186/s12864-017-3902-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5516393PMC
July 2017
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