ORCID Profile
0000-0002-3666-7240
Current Organisations
University of Tasmania
,
University of Melbourne
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Publisher: Oxford University Press (OUP)
Date: 28-03-2023
Abstract: PHYTOCHROME KINASE SUBSTRATE (PKS) proteins are involved in light-modulated changes in growth orientation. They act downstream of phytochromes to control hypocotyl gravitropism in the light and act early in phototropin signaling. Despite their importance for plant development, little is known about their molecular mode of action, except that they belong to a protein complex comprising phototropins at the plasma membrane (PM). Identifying evolutionary conservation is one approach to revealing biologically important protein motifs. Here, we show that PKS sequences are restricted to seed plants and that these proteins share 6 motifs (A to F from the N to the C terminus). Motifs A and D are also present in BIG GRAIN, while the remaining 4 are specific to PKSs. We provide evidence that motif C is S-acylated on highly conserved cysteines, which mediates the association of PKS proteins with the PM. Motif C is also required for PKS4-mediated phototropism and light-regulated hypocotyl gravitropism. Finally, our data suggest that the mode of PKS4 association with the PM is important for its biological activity. Our work, therefore, identifies conserved cysteines contributing to PM association of PKS proteins and strongly suggests that this is their site of action to modulate environmentally regulated organ positioning.
Publisher: Wiley
Date: 25-08-2014
DOI: 10.1111/TPJ.12625
Abstract: In Arabidopsis, SEUSS (SEU) and SEUSS-LIKE 2 (SLK2) are components of the LEUNIG (LUG) repressor complex that coordinates various aspects of post-embryonic development. The complex also plays a critical role during embryogenesis, as seu slk2 double mutants have small, narrow cotyledons and lack a shoot apical meristem (SAM). Here we show that seu slk2 double mutant embryos exhibit delayed cotyledon outgrowth and that this is associated with altered PIN-FORMED1 (PIN1) expression and localisation during the early stages of embryogenesis. These observations suggest that SEU and SLK2 promote the transition to bilateral symmetry by modulating auxin distribution in the embryonic shoot. This study also shows that loss of SAM formation in seu slk2 mutants is associated with reduced expression of the class I KNOX (KNOXI) genes SHOOTMERISTEMLESS (STM), BREVIPEDICELLUS and KNAT2. Furthermore, elevating STM expression in seu slk2 mutant embryos was sufficient to restore SAM formation but not post-embryonic activity, while both SAM formation and activity were rescued when SLK2 expression was restored in either the cotyledons or boundary regions. These results demonstrate that SEU and SLK2 function redundantly to promote embryonic shoot development and likely act through a non-cell autonomous pathway to promote KNOXI activity.
Publisher: Oxford University Press (OUP)
Date: 07-03-2016
DOI: 10.1104/PP.15.01919
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.ENVRES.2022.113762
Abstract: Allergic rhinitis affects half a billion people globally, including a fifth of the Australian population. As the foremost outdoor allergen source, ambient grass pollen exposure is likely to be altered by climate change. The AusPollen Partnership aimed to standardize pollen monitoring and examine broad-scale biogeographical and meteorological factors influencing interannual variation in seasonality of grass pollen aerobiology in Australia. Daily airborne grass and other pollen concentrations in four eastern Australian cities separated by over 1700 km, were simultaneously monitored using Hirst-style s lers following the Australian Interim Pollen and Spore Monitoring Standard and Protocols over four seasons from 2016 to 2020. The grass seasonal pollen integral was determined. Gridded rainfall, temperature, and satellite-derived grassland sources up to 100 km from the monitoring site were analysed. The complexity of grass pollen seasons was related to latitude with multiple major summer-autumn peaks in Brisbane, major spring and minor summer peaks in Sydney and Canberra, and single major spring peaks occurring in Melbourne. The subtropical site of Brisbane showed a higher proportion of grass out of total pollen than more temperate sites. The magnitude of the grass seasonal pollen integral was correlated with pasture greenness, rainfall and number of days over 30 °C, preceding and within the season, up to 100 km radii from monitoring sites. Interannual fluctuations in Australian grass pollen season magnitude are strongly influenced by regional biogeography and both pre- and in-season weather. This first continental scale, Southern Hemisphere standardized aerobiology dataset forms the basis to track shifts in pollen seasonality, bio ersity and impacts on allergic respiratory diseases.
Publisher: Frontiers Media SA
Date: 25-05-2021
Abstract: Arabinogalactan-proteins (AGPs) are members of the hydroxyproline-rich glycoprotein (HRGP) superfamily, a group of highly erse proteoglycans that are present in the cell wall, plasma membrane as well as secretions of almost all plants, with important roles in many developmental processes. The role of GALT8 (At1g22015), a Glycosyltransferase-31 (GT31) family member of the Carbohydrate-Active Enzyme database (CAZy), was examined by biochemical characterization and phenotypic analysis of a galt8 mutant line. To characterize its catalytic function, GALT8 was heterologously expressed in tobacco leaves and its enzymatic activity tested. GALT8 was shown to be a β-(1,3)-galactosyltransferase (GalT) that catalyzes the synthesis of a β-(1,3)-galactan, similar to the in vitro activity of KNS4/UPEX1 (At1g33430), a homologous GT31 member previously shown to have this activity. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) confirmed the products were of 2-6 degree of polymerisation (DP). Previous reporter studies showed that GALT8 is expressed in the central and synergid cells, from whence the micropylar endosperm originates after the fertilization of the central cell of the ovule. Homozygous mutants have multiple seedling phenotypes including significantly shorter hypocotyls and smaller leaf area compared to wild type (WT) that are attributable to defects in female gametophyte and/or endosperm development. KNS4/UPEX1 was shown to partially complement the galt8 mutant phenotypes in genetic complementation assays suggesting a similar but not identical role compared to GALT8 in β-(1,3)-galactan biosynthesis. Taken together, these data add further evidence of the important roles GT31 β-(1,3)-GalTs play in elaborating type II AGs that decorate AGPs and pectins, thereby imparting functional consequences on plant growth and development.
Publisher: Elsevier BV
Date: 03-2021
Publisher: Public Library of Science (PLoS)
Date: 08-10-2013
Publisher: Oxford University Press (OUP)
Date: 22-02-2010
DOI: 10.1093/JXB/ERQ015
Publisher: Oxford University Press (OUP)
Date: 03-2015
Abstract: The current dogma for cell wall polysaccharide biosynthesis is that cellulose (and callose) is synthesized at the plasma membrane (PM), whereas matrix phase polysaccharides are assembled in the Golgi apparatus. We provide evidence that (1,3 ,4)-β-d-glucan (mixed-linkage glucan [MLG]) does not conform to this paradigm. We show in various grass (Poaceae) species that MLG-specific antibody labeling is present in the wall but absent over Golgi, suggesting it is assembled at the PM. Antibodies to the MLG synthases, cellulose synthase-like F6 (CSLF6) and CSLH1, located CSLF6 to the endoplasmic reticulum, Golgi, secretory vesicles, and the PM and CSLH1 to the same locations apart from the PM. This pattern was recreated upon expression of VENUS-tagged barley (Hordeum vulgare) CSLF6 and CSLH1 in Nicotiana benthamiana leaves and, consistent with our biochemical analyses of native grass tissues, shown to be catalytically active with CSLF6 and CSLH1 in PM-enriched and PM-depleted membrane fractions, respectively. These data support a PM location for the synthesis of MLG by CSLF6, the predominant enzymatically active isoform. A model is proposed to guide future experimental approaches to dissect the molecular mechanism(s) of MLG assembly.
Publisher: Wiley
Date: 25-03-2018
DOI: 10.1111/NPH.15090
Abstract: A plethora of developmental and physiological processes in land plants is influenced by auxin, to a large extent via alterations in gene expression by AUXIN RESPONSE FACTORs (ARFs). The canonical auxin transcriptional response system is a land plant innovation, however, charophycean algae possess orthologues of at least some classes of ARF and AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) genes, suggesting that elements of the canonical land plant system existed in an ancestral alga. We reconstructed the phylogenetic relationships between streptophyte ARF and AUX/IAA genes and functionally characterized the solitary class C ARF, MpARF3, in Marchantia polymorpha. Phylogenetic analyses indicate that multiple ARF classes, including class C ARFs, existed in an ancestral alga. Loss- and gain-of-function MpARF3 alleles result in pleiotropic effects in the gametophyte, with MpARF3 inhibiting differentiation and developmental transitions in multiple stages of the life cycle. Although loss-of-function Mparf3 and Mpmir160 alleles respond to exogenous auxin treatments, strong miR-resistant MpARF3 alleles are auxin-insensitive, suggesting that class C ARFs act in a context-dependent fashion. We conclude that two modules independently evolved to regulate a pre-existing ARF transcriptional network. Whereas the auxin-TIR1-AUX/IAA pathway evolved to repress class A/B ARF activity, miR160 evolved to repress class C ARFs in a dynamic fashion.
Publisher: Public Library of Science (PLoS)
Date: 12-04-2018
Publisher: Copernicus GmbH
Date: 15-02-2019
Publisher: Elsevier BV
Date: 10-2022
Publisher: Wiley
Date: 14-06-2012
Publisher: SAGE Publications
Date: 2021
DOI: 10.1177/21526567211010728
Abstract: The most severe thunderstorm asthma (TA) event occurred in Melbourne on the 21st November 2016 and during this period, daily pollen information was available and accessible on smart devices via an App. An integrated survey within the App allows users to self-report symptoms. To explore patterns of symptom survey results during the period when the TA event occurred. Symptom data from the Melbourne Pollen Count and Forecast App related to asthma history, hay fever symptoms, and medication use was explored. A one-week control period before and after the event was considered. Chi-square tests and logistic regression were used to assess associations between sex, age, symptoms, and medication use. Of the 28,655 responses, during the 2016 pollen season, younger (18 to 40 years) males, with no hay fever and no asthma were the most single and regular responders. During the TA event for new users, sex was only significantly associated with hay fever ( p = 0.008) of which 60.2% of females’ responses reported having hay fever, while 43% of males’ responses did not. Those with mild symptoms peaked during the TA event. Many in iduals completed the survey on the app for the first time during the TA event indicating the potential of digital technologies to be used as indicators of health risk among populations at risk of TA events.
Publisher: Elsevier BV
Date: 02-2018
Publisher: American Meteorological Society
Date: 02-2020
Abstract: In November 2016, an unprecedented epidemic thunderstorm asthma event in Victoria, Australia, resulted in many thousands of people developing breathing difficulties in a very short period of time, including 10 deaths, and created extreme demand across the Victorian health services. To better prepare for future events, a pilot forecasting system for epidemic thunderstorm asthma (ETSA) risk has been developed for Victoria. The system uses a categorical risk-based approach, combining operational forecasting of gusty winds in severe thunderstorms with statistical forecasts of high ambient grass pollen concentrations, which together generate the risk of epidemic thunderstorm asthma. This pilot system provides the first routine daily epidemic thunderstorm asthma risk forecasting service in the world that covers a wide area, and integrates into the health, ambulance, and emergency management sector. Epidemic thunderstorm asthma events have historically occurred infrequently, and no event of similar magnitude has impacted the Victorian health system since. However, during the first three years of the pilot, 2017–19, two high asthma presentation events and four moderate asthma presentation events were identified from public hospital emergency department records. The ETSA risk forecasts showed skill in discriminating between days with and without health impacts. However, even with hindsight of the actual weather and airborne grass pollen conditions, some high asthma presentation events occurred in districts that were assessed as low risk for ETSA, reflecting the challenge of predicting this unusual phenomenon.
Publisher: The Company of Biologists
Date: 2013
DOI: 10.1242/DEV.084582
Abstract: Floral organs are usually arranged in concentric whorls of sepals, petals, stamens and carpels. How founder cells of these organs are specified is unknown. In Arabidopsis, the PETAL LOSS (PTL) transcription factor functions in the sepal whorl, where it restricts the size of the inter-sepal zone. Genetic evidence suggests that PTL acts to support a petal initiation signal active in the adjacent whorl. Here we aimed to characterise the signal by identifying enhancers that disrupt initiation of the remaining petals in ptl mutants. One such enhancer encodes the auxin influx protein AUX1. We have established that auxin is a direct and mobile petal initiation signal by promoting its biosynthesis in the inter-sepal zone in ptl mutant plants and restoring nearby petal initiation. Consistent with this, loss of PTL function disrupts DR5 expression, an auxin-inducible indicator of petal-initiation sites. The signalling network was extended by demonstrating that: (1) loss of RABBIT EARS (RBE) function apparently disrupts the same auxin influx process as PTL (2) the action of AUX1 is supported by AXR4, its upstream partner in auxin influx (3) polar auxin transport, which is controlled by PINOID (PID) and PIN-FORMED1 (PIN1), functions downstream of PTL and (4) the action of pmd-1d, a dominant modifier of the ptl mutant phenotype, is dependent on auxin transport. Thus, loss of PTL function disrupts auxin dynamics, allowing the role of auxin in promoting petal initiation to be revealed.
Publisher: Cold Spring Harbor Laboratory
Date: 17-09-2023
Publisher: Public Library of Science (PLoS)
Date: 20-04-2015
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.SCITOTENV.2019.135147
Abstract: Allergic Rhinitis (AR) affects over half a billion people worldwide with an estimated prevalence of 1 in 5 in iduals in developed countries. Although ambient pollen exposure is a causal factor in AR, the symptom-exposure relationship is typically not studied in the broader community but in small, well-characterised cohorts drawn from clinical populations. To identify relationships between AR symptoms in the community and a range of environmental factors, we used a database containing over 96,000 symptom score reports collected over a 3-year period (2014-2016) through freely available smartphone apps released in two Australian cities, Melbourne and Canberra. Ambient pollen levels and symptom scores were strongly related, with grass pollen explaining most of the symptom variation. Other factors correlated with higher symptom scores included temperature (R > 0.73) and wind speed (R > 0.75). In general, worse symptom scores were reported by younger participants, women, and those who had taken medication for AR in the preceding 24 h. The strength of this relationship varied between the two cities. Smartphone-based symptom surveys offer a cost-effective means of studying real-world risk factors for AR in a broader 'extra-clinical' population.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-04-2022
Abstract: Atmospheric changes in pollen concentration may affect human health by triggering various allergic processes. We sought to assess if changes in pollen concentrations were associated with different acute coronary syndrome (ACS) subtype presentations and short‐term clinical outcomes. We analyzed data in consecutive patients presenting with ACS (unstable angina, non–ST‐segment–elevation myocardial infarction, and ST‐segment–elevation myocardial infarction) treated with percutaneous coronary intervention between January 2014 and December 2017 and enrolled in the VCOR (Victorian Cardiac Outcomes Registry). Baseline characteristics were compared among patients exposed to different grass and total pollen concentrations. The primary outcome was occurrence of ACS subtypes and 30‐day major adverse cardiac and cerebrovascular events (composite of mortality, myocardial infarction, stent thrombosis, target vessel revascularization, or stroke). Of 15 379 patients, 7122 (46.3%) presented with ST‐segment–elevation myocardial infarction, 6781 (44.1%) with non–ST‐segment–elevation myocardial infarction, and 1476 (9.6%) with unstable angina. The mean age was 62.5 years, with men comprising 76% of patients. No association was observed between daily or seasonal grass and total pollen concentrations with the frequency of ACS subtype presentation. However, grass and total pollen concentrations in the preceding days (2‐day average for grass pollen and 7‐day average for total pollen) correlated with in‐hospital mortality (odds ratio [OR], 2.17 [95% CI, 1.12–4.21] P =0.021 and OR, 2.78 [95% CI, 1.00–7.74] P =0.05), respectively, with a trend of 2‐day grass pollen for 30‐day major adverse cardiac and cerebrovascular events (OR, 1.50 [95% CI, 0.97–2.32] P =0.066). Increased pollen concentrations were not associated with differential ACS subtype presentation but were significantly related to in‐hospital mortality following percutaneous coronary intervention, underscoring a potential biologic link between pollen exposure and clinical outcomes.
Publisher: Frontiers Media SA
Date: 08-02-2017
Publisher: Wiley
Date: 09-2017
DOI: 10.1111/IMJ.56_13578
Publisher: The Company of Biologists
Date: 15-01-2018
DOI: 10.1242/JCS.207373
Abstract: Plant cells are surrounded by a strong polysaccharide-rich cell wall that aids in determining the overall form, growth and development of the plant body. Indeed, the unique shapes of the 40-odd cell types in plants are determined by their walls, as removal of the cell wall results in spherical protoplasts that are amorphic. Hence, assembly and remodeling of the wall is essential in plant development. Most plant cell walls are composed of a framework of cellulose microfibrils that are cross-linked to each other by heteropolysaccharides. The cell walls are highly dynamic and adapt to the changing requirements of the plant during growth. However, despite the importance of plant cell walls for plant growth and for applications that we use in our daily life such as food, feed and fuel, comparatively little is known about how they are synthesized and modified. In this Cell Science at a Glance article and accompanying poster, we aim to illustrate the underpinning cell biology of the synthesis of wall carbohydrates, and their incorporation into the wall, in the model plant Arabidopsis.
Publisher: MDPI AG
Date: 09-01-2021
Abstract: Adolescent asthma is still a major problem with poor adherence to treatment. Globally, adolescents are devoted users of smartphone technologies and app use in asthma self-management may improve adherence. The objective of this systematic review is to assess the feasibility and efficacy of mobile technology in improving asthma outcomes in adolescents. We conducted an extensive review of the peer-review literature of studies with populations consisting of children and adolescents under 18 years in seven bibliographic databases and Google Scholar. All study designs were considered. Quality assessment of included studies were independently assessed and reported. The search identified 291 articles of the 16 eligible full-text papers, 8 met the review criteria, reporting two interventional, two qualitative and four observational studies. S les ranged from 12 to 21 participants. Heterogeneity related to study design and the methods of the included studies prevented meta-analysis. Nevertheless, the intervention studies reported a positive effect of smartphone apps on asthma control, medication adherence and self-efficacy. Smartphone apps may be an effective asthma control tool especially among adolescents who are major users of smartphones however, conclusions are limited by a lack of controlled trials and adequate s le sizes.
Publisher: Oxford University Press (OUP)
Date: 15-06-2021
DOI: 10.1093/PCP/PCAB087
Abstract: Growth, development, structure as well as dynamic adaptations and remodeling processes in plants are largely controlled by properties of their cell walls. These intricate wall structures are mostly made up of different sugars connected through specific glycosidic linkages but also contain many glycosylated proteins. A key plant sugar that is present throughout the plantae, even before the ergence of the land plant lineage, but is not found in animals, is l-arabinose (l-Ara). Here, we summarize and discuss the processes and proteins involved in l-Ara de novo synthesis, l-Ara interconversion, and the assembly and recycling of l-Ara-containing cell wall polymers and proteins. We also discuss the biological function of l-Ara in a context-focused manner, mainly addressing cell wall–related functions that are conferred by the basic physical properties of arabinose-containing polymers/compounds. In this article we explore these processes with the goal of directing future research efforts to the many exciting yet unanswered questions in this research area.
Publisher: Oxford University Press (OUP)
Date: 25-09-2017
DOI: 10.1105/TPC.17.00309
Publisher: Oxford University Press (OUP)
Date: 09-11-2016
DOI: 10.1104/PP.16.01385
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.TPLANTS.2019.02.011
Abstract: Cellulose is an essential morphogenic polysaccharide that is central to the stability of plant cell walls and provides an important raw material for a range of plant-based fiber and fuel industries. The past decade has seen a substantial rise in the identification of cellulose synthesis-related components and in our understanding of how these components function. Much of this research has been conducted in Arabidopsis thaliana (arabidopsis) however, it has become increasingly evident that many of the components and their functions are conserved. We provide here an overview of cellulose synthesis 'core' components. The evolution and coexpression patterns of these components provide important insight into how cellulose synthesis evolved and the potential for the components to work as functional units during cellulose production.
Publisher: Copernicus GmbH
Date: 15-02-2019
DOI: 10.5194/GMD-2019-43
Abstract: Abstract. We present the first representation of grass pollen in a 3D dispersion model anywhere in Australia, tested using observations from eight counting sites in Victoria. The region's population has high rates of allergic rhinitis and asthma, and this has been linked to the high incidence of grass pollen allergy. Despite this, grass pollen dispersion in the Australian atmosphere has not been studied previously, and its source strength is untested. We describe ten pollen emission source methodologies examining the strengths of different immediate and seasonal timing functions, and spatial distribution of the sources. The timing function assumes a smooth seasonal term, modulated by an hourly meteorological function. A simple Gaussian representation of the pollen season worked well (average r = 0.54), but lacks the spatial and temporal variation that the satellite-derived Enhanced Vegetation Index (EVI) data can provide. However poor results were obtained using the EVI gradient (average r = 0.35), which gives the timing when grass turns from maximum greenness to a drying and flowering period this is due to the greater spatial and temporal variability from this combined spatial and seasonal term. Better results were obtained using statistical methods that combine elements of the EVI dataset, a smooth seasonal term and instantaneous variation based on historical grass pollen observations (average r = 0.69). The seasonal magnitude is inferred from the maximum winter-time EVI, while the timing of the peak of the season was based on the day of the year when the EVI falls to 0.05 below its winter maximum. Measurements are vital to monitor changes in the pollen season, and the new pollen measurement sites in the Victorian network should be maintained.
Publisher: Springer Science and Business Media LLC
Date: 09-06-2016
DOI: 10.1038/NCOMMS11656
Abstract: As the most abundant biopolymer on Earth, cellulose is a key structural component of the plant cell wall. Cellulose is produced at the plasma membrane by cellulose synthase (CesA) complexes (CSCs), which are assembled in the endomembrane system and trafficked to the plasma membrane. While several proteins that affect CesA activity have been identified, components that regulate CSC assembly and trafficking remain unknown. Here we show that STELLO1 and 2 are Golgi-localized proteins that can interact with CesAs and control cellulose quantity. In the absence of STELLO function, the spatial distribution within the Golgi, secretion and activity of the CSCs are impaired indicating a central role of the STELLO proteins in CSC assembly. Point mutations in the predicted catalytic domains of the STELLO proteins indicate that they are glycosyltransferases facing the Golgi lumen. Hence, we have uncovered proteins that regulate CSC assembly in the plant Golgi apparatus.
Publisher: Informa UK Limited
Date: 02-2016
Publisher: Cold Spring Harbor Laboratory
Date: 09-07-2022
DOI: 10.1101/2022.07.08.499325
Abstract: PHYTOCHROME KINASE SUBSTRATE (PKS) proteins are involved in light-regulated growth orientation responses. They act downstream of phytochromes to control hypocotyl gravitropism in the light and act early in phototropin signaling. Despite their importance for plant development, little is known about their molecular mode of action except that they belong to a protein complex comprising the phototropins at the plasma membrane. Identifying evolutionarily conservation is one approach to reveal biologically important protein motifs. Here, we show that PKS sequences are restricted to seed plants and that these proteins share 6 motifs (A to F from the N- to the C-terminus). While motif D is also found in BIG GRAIN proteins the remining domains are PKS specific. We provide evidence that motif C is S-acylated on highly conserved cysteines, which mediates PKS protein association with the plasma membrane. This motif is also required for PKS4-mediated phototropism and control of hypocotyl gravitropism in the light. Finally, our data suggests that the mode of PKS4 plasma membrane association is important for its biological activity. Our work identifies the mode of plasma membrane association of PKS proteins and strongly suggests that this is their site of action to modulate environmentally regulated organ positioning.
Publisher: Informa UK Limited
Date: 04-07-2018
Publisher: Springer Science and Business Media LLC
Date: 20-02-2019
DOI: 10.1038/S41467-019-08780-3
Abstract: Microtubules are filamentous structures necessary for cell ision, motility and morphology, with dynamics critically regulated by microtubule-associated proteins (MAPs). Here we outline the molecular mechanism by which the MAP, COMPANION OF CELLULOSE SYNTHASE1 (CC1), controls microtubule bundling and dynamics to sustain plant growth under salt stress. CC1 contains an intrinsically disordered N-terminus that links microtubules at evenly distributed points through four conserved hydrophobic regions. By NMR and live cell analyses we reveal that two neighboring residues in the first hydrophobic binding motif are crucial for the microtubule interaction. The microtubule-binding mechanism of CC1 is reminiscent to that of the prominent neuropathology-related protein Tau, indicating evolutionary convergence of MAP functions across animal and plant cells.
Publisher: Oxford University Press (OUP)
Date: 05-02-2016
DOI: 10.1104/PP.15.02005
Publisher: Proceedings of the National Academy of Sciences
Date: 08-03-2021
Abstract: Cellulose is the most abundant biopolymer on Earth and has many potential industrial applications, such as renewable energy and sustainable materials. Here we report the apo and UDP-glucose (UDP-Glc)–bound crystal structures of the catalytic domain of Arabidopsis thaliana CESA3. Our results offer a structural basis for how the substrate UDP-Glc and a metal ion, Mn 2+ , which is required for cellulose synthesis, are coordinated in plant CESAs. Furthermore, our structure reveals that CESAs may form homodimers through interactions between specific beta strands that likely aid in the early stages of CESA complex formation.
Publisher: Oxford University Press (OUP)
Date: 06-2021
DOI: 10.1038/S41438-021-00572-5
Abstract: Transfer RNAs (tRNA) are crucial adaptor molecules between messenger RNA (mRNA) and amino acids. Recent evidence in plants suggests that dicistronic tRNA-like structures also act as mobile signals for mRNA transcripts to move between distant tissues. Co-transcription is not a common feature in the plant nuclear genome and, in the few cases where polycistronic transcripts have been found, they include non-coding RNA species, such as small nucleolar RNAs and microRNAs. It is not known, however, the extent to which dicistronic transcripts of tRNA and mRNAs are expressed in field-grown plants, or the factors contributing to their expression. We analysed tRNA–mRNA dicistronic transcripts in the major horticultural crop grapevine ( Vitis vinifera ) using a novel pipeline developed to identify dicistronic transcripts from high-throughput RNA-sequencing data. We identified dicistronic tRNA–mRNA in leaf and berry s les from 22 commercial vineyards. Of the 124 tRNA genes that were expressed in both tissues, 18 tRNA were expressed forming part of 19 dicistronic tRNA–mRNAs. The presence and abundance of dicistronic molecules was tissue and geographic sub-region specific. In leaves, the expression patterns of dicistronic tRNA–mRNAs significantly correlated with tRNA expression, suggesting that their transcriptional regulation might be linked. We also found evidence of syntenic genomic arrangements of tRNAs and protein-coding genes between grapevine and Arabidopsis thaliana , and widespread prevalence of dicistronic tRNA–mRNA transcripts among vascular land plants but no evidence of these transcripts in non-vascular lineages. This suggests that the appearance of plant vasculature and tRNA–mRNA occurred concurrently during the evolution of land plants.
Publisher: Copernicus GmbH
Date: 04-06-2019
Abstract: Abstract. We present the first representation of grass pollen in a 3-D dispersion model in Australia, tested using observations from eight counting sites in Victoria. The region's population has high rates of allergic rhinitis and asthma, and this has been linked to the high incidence of grass pollen allergy. Despite this, grass pollen dispersion in the Australian atmosphere has not been studied previously, and its source strength is untested. We describe 10 pollen emission source methodologies examining the strengths of different immediate and seasonal timing functions, and the spatial distribution of the sources. The timing function assumes a smooth seasonal term, modulated by an hourly meteorological function. A simple Gaussian representation of the pollen season worked well (average r=0.54), but lacked the spatial and temporal variation that the satellite-derived enhanced vegetation index (EVI) can provide. However, poor results were obtained using the EVI gradient (average r=0.35), which provides the timing when grass turns from maximum greenness to a drying and flowering period this is due to noise in the spatial and temporal variability from this combined spatial and seasonal term. Better results were obtained using statistical methods that combine elements of the EVI dataset, a smooth seasonal term and instantaneous variation based on historical grass pollen observations (average r=0.69). The seasonal magnitude is inferred from the maximum winter-time EVI, whereas the timing of the season peak is based on the day of the year when the EVI falls to 0.05 below its winter maximum. Measurements are vital to monitor changes in the pollen season, and the new pollen measurement sites in the Victorian network should be maintained.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Springer Science and Business Media LLC
Date: 18-07-2019
No related grants have been discovered for Edwin Lampugnani.