ORCID Profile
0000-0002-9940-5926
Current Organisations
La Trobe University
,
Australian Government Department of Agriculture Fisheries and Forestry
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Publisher: Springer Science and Business Media LLC
Date: 02-2004
Publisher: Wiley
Date: 17-11-2011
DOI: 10.1111/J.1365-3040.2011.02452.X
Abstract: Water deficit affects tree growth and limits wood production. In an attempt to identify the molecular triggers of adaptation mechanisms to water deficit in Eucalyptus, we investigated protein expression patterns of two ecophysiologically contrasted Eucalyptus genotypes. They were grown in the field in either natural conditions or irrigated for 7 weeks during the dry season in the Republic of Congo. At the phenotypic level, genotype (G), treatment (T) and/or G × T interaction effects were observed for above- and below-ground biomass-related traits. At the molecular level, changes in protein abundance were recorded in leaves (acidic pH 4-7, and basic pH 7-11, proteomes) and stems (acidic proteome) using two-dimensional gel electrophoresis (2-DE). One third of the detected protein spots displayed significant G, T and/or G × T effects, and 158 of them were identified by tandem mass spectrometry (LC-MS/MS) analysis. Thus, several proteins whose molecular plasticity was genetically controlled (i.e. G × T effect) were revealed, highlighting adaptive mechanisms to water deficit specific to each genotype, namely cell wall modification, cell detoxification and osmoregulation. Transcript abundances corresponding to G × T proteins were also investigated by quantitative RT-PCR. These proteins represent relevant targets to improve drought resistance in this ecologically and economically important forest tree genus.
Publisher: Oxford University Press (OUP)
Date: 19-09-2008
DOI: 10.1093/JXB/ERN234
Publisher: Frontiers Media SA
Date: 27-10-2015
Publisher: Cold Spring Harbor Laboratory
Date: 29-03-2020
DOI: 10.1101/2020.03.27.011973
Abstract: Legumes form a symbiosis with rhizobia that convert atmospheric nitrogen (N 2 ) to ammonia which they provide to the plant in return for a carbon and nutrient supply. Nodules, developed as part of the symbiosis, harbor rhizobia which are enclosed in the plant-derived symbiosome membrane (SM), to form a symbiosome. In the mature nodule all exchanges between the symbionts occur across the SM. Here we characterize GmYSL7, a member of Yellow stripe-like family which is localized to the SM in soybean nodules. It is expressed specifically in nodule infected cells with expression peaking soon after nitrogenase becomes active. Although most members of the family transport metal complexed with phytosiderophores, GmYSL7 does not. It transports oligopeptides of between four and 12 amino acids. Silencing of GmYSL7 reduces nitrogenase activity and blocks development when symbiosomes contain a single bacteroid. RNAseq of nodules in which GmYSL7 is silenced suggests that the plant initiates a defense response against the rhizobia. There is some evidence that metal transport in the nodules is dysregulated, with upregulation of genes encoding ferritin and vacuolar iron transporter family and downregulation of a gene encoding nicotianamine synthase. However, it is not clear whether the changes are a result of the reduction of nitrogen fixation and the requirement to store excess iron or an indication of a role of GmYSL7 in regulation of metal transport in the nodules. Further work to identify the physiological substrate for GmYSL7 will allow clarification of this role. GmYSL7 is a symbiosome membrane peptide transporter that is essential for symbiotic nitrogen fixation that when silenced blocks symbiosome development.
Publisher: Frontiers Media SA
Date: 03-12-2019
Publisher: OMICS Publishing Group
Date: 2013
Publisher: Springer Science and Business Media LLC
Date: 14-03-2009
DOI: 10.1007/S00299-009-0688-0
Abstract: The enzyme Cinnamyl Alcohol Dehydrogenase (CAD) catalyses the last step of lignin monomer synthesis, and is considered as a molecular marker of cell wall lignification in different plants species. Here, we report the isolation and analysis of 5' flanking genomic DNA regions upstream to the CAD gene, from two conifers, i.e. white spruce (Picea glauca (Moench) Voss) and loblolly pine (Pinus taeda L.). Sequence comparisons with available CAD gene promoters from angiosperms highlighted the conservation of cis-elements matching MYB, WRKY and bHLH binding sites. Functional characterization of the P. glauca CAD promoter used P. glauca seedlings stably transformed with a DNA fragment of 1,163 base pairs (PgCAD) fused to the beta-glucuronidase (GUS) gene. Histochemical observations of different vegetative organs of the transgenic trees showed that this sequence was sufficient to drive GUS expression in lignifying tissues, and more specifically in differentiating xylem cells. Quantitative RT-PCR experiments also indicated that the native CAD gene was preferentially expressed in differentiating xylem both in stems and roots. In addition, GUS expression driven by the PgCAD promoter was wound-inducible which was consistent with the accumulation of CAD mRNA in response to jasmonate application and mechanical wounding. The spruce CAD promoter represents a valuable tool for research and biotechnology applications related to xylem and wood.
Publisher: Wiley
Date: 12-2008
DOI: 10.1111/J.1469-8137.2008.02615.X
Abstract: One approach for investigating the molecular basis of wood formation is to integrate microarray profiling data sets and sequence analyses, comparing tree species with model plants such as Arabidopsis. Conifers may be included in comparative studies thanks to large-scale expressed sequence tag (EST) analyses, which enable the development of cDNA microarrays with very significant genome coverage. A microarray of 10,400 low-redundancy sequences was designed starting from white spruce (Picea glauca (Moench.) Voss) cDNAs. Computational procedures that were developed to ensure broad transcriptome coverage and efficient PCR lification were used to select cDNA clones, which were re-sequenced in the microarray manufacture process. White spruce transcript profiling experiments that compared secondary xylem to phloem and needles identified 360 xylem-preferential gene sequences. The functional annotations of all differentially expressed sequences were highly consistent with the results of similar analyses carried out in angiosperm trees and herbaceous plants. Computational analyses comparing the spruce microarray sequences and core xylem gene sets from Arabidopsis identified 31 transcripts that were highly conserved in angiosperms and gymnosperms, in terms of both sequence and xylem expression. Several other spruce sequences have not previously been linked to xylem differentiation (including genes encoding TUBBY-like domain proteins (TLPs) and a gibberellin insensitive (gai) gene sequence) or were shown to encode proteins of unknown function encompassing erse conserved domains of unknown function.
Publisher: Frontiers Media SA
Date: 05-2014
Publisher: Future Science Ltd
Date: 2013
DOI: 10.2144/000113969
Abstract: Here we present a quick and low-cost method to separate the different layers of tissue from the ovules and young seeds of cotton (Gossypium hirsutum L.) for use in high- and low-throughput molecular applications. This method is performed at room temperature using standard laboratory equipment and does not require embedding of the s les, time-consuming fixation, or micro-sectioning procedures. We show that the three main tissues can be efficiently separated from isolated ovules collected on the day of anthesis. RNA and genomic DNA extracted from tissues separated by this method are of good quality and suitable for a variety of molecular applications to study the early stages of cotton seed and fiber development.
Publisher: Cold Spring Harbor Laboratory
Date: 05-03-2020
DOI: 10.1101/2020.03.03.975805
Abstract: Legumes establish symbiotic relationships with soil bacteria (rhizobia), housed in nodules on plant roots. The plant supplies carbon substrates and other nutrients to the bacteria in exchange for fixed nitrogen. The exchange occurs across a plant-derived symbiosome membrane (SM), which encloses rhizobia to form a symbiosome. Iron supplied by the plant is crucial for the rhizobial enzyme nitrogenase that catalyses N 2 fixation, but the SM iron transporter has not been identified. We use complementation of yeast and plant mutants, real-time PCR, hairy root transformation, microscopy and proteomics to demonstrate the role of soybean GmVTL1 and 2. Both are members of the vacuolar iron transporter family and homologous to Lotus japonicus SEN1 (LjSEN1), previously shown to be essential for N 2 fixation. GmVTL1 expression is enhanced in nodule infected cells and both proteins are localised to the SM. GmVTL1 and 2 transport iron in yeast and GmVTL1 restores N 2 fixation when expressed in the Ljsen1 mutant. Three GmVTL1 amino acid substitutions that reduce iron transport in yeast also block N 2 fixation in Ljsen1 plants. We conclude GmVTL1 is responsible for transport of iron across the SM to bacteroids and plays a crucial role in the N 2 -fixing symbiosis.
Publisher: CABI Publishing
Date: 2011
Abstract: Lignin, the second most abundant plant polymer on earth, has always been of great interest for research with regard to its biological roles and potential for useful modification. Over the last few decades, numerous studies have considerably enriched our knowledge of lignin biosynthesis. In the first part, a revision of lignin composition and synthesis is described, highlighting the key genes shown to be implicated in the lignification process occurring during secondary cell wall (SCW) formation in plants. Availability of genome sequencing data has brought about useful information concerning the different gene families of the lignin biosynthesis pathway. These data can be exploited to isolate the members that are more specific to the SCW formation process through combination of sequence homology or specific transcript-profiling techniques. This review also summarizes our current knowledge on the transcriptional regulation of lignin biosynthesis, particularly the R2R3-MYB and NAC transcription factor (TF) families. Strategies of lignin modification for the production of second-generation biofuels are also discussed.
Publisher: Frontiers Media SA
Date: 25-04-2022
Publisher: Wiley
Date: 16-06-2014
Abstract: Differential expression of soluble proteins was explored in roots of metallicolous (M) and non-M (NM) plants of Agrostis capillaris L. exposed to increasing Cu to partially identify molecular mechanisms underlying higher Cu tolerance in M plants. Plants were cultivated for 2 months on perlite with a CuSO4 (1-30 μM) spiked-nutrient solution. Soluble proteins extracted by the trichloroacetic acid/acetone procedure were separated with 2DE (linear 4-7 pH gradient). After Coomassie Blue staining and image analysis, 19 proteins differentially expressed were identified using LC-MS/MS and Expressed Sequence Tag (ESTs) databases. At supra-optimal Cu exposure (15-30 μM), glycolysis was likely altered in NM roots with increased production of glycerone-P and methylglyoxal based on overexpression of triosephosphate isomerase and fructose bisphosphate aldolase. Changes in tubulins and higher expressions of 5-methyltetrahydropteroyltriglutamatehomocysteine methyltransferase and S-adenosylmethionine synthase underpinned impacts on the cytoskeleton and stimulation of ethylene metabolism. Increased l-methionine and S-adenosylmethionine amounts may also facilitate production of nicotianamine, which complexes Cu, and of l-cysteine, needed for metallothioneins and GSH. In M roots, the increase of [Cu/Zn] superoxide dismutase suggested a better detoxification of superoxide, when Cu exposure rose. Higher Cu-tolerance of M plants would rather result from simultaneous cooperation of various processes than from a specific mechanism.
Publisher: Oxford University Press (OUP)
Date: 23-08-2010
DOI: 10.1093/JXB/ERQ196
Publisher: Springer Science and Business Media LLC
Date: 08-06-2011
Publisher: MDPI AG
Date: 10-01-2022
DOI: 10.3390/IJMS23020713
Abstract: Bread wheat is the most widely cultivated crop worldwide, used in the production of food products and a feed source for animals. Selection tools that can be applied early in the breeding cycle are needed to accelerate genetic gain for increased wheat production while maintaining or improving grain quality if demand from human population growth is to be fulfilled. Proteomics screening assays of wheat flour can assist breeders to select the best performing breeding lines and discard the worst lines. In this study, we optimised a robust LC–MS shotgun quantitative proteomics method to screen thousands of wheat genotypes. Using 6 cultivars and 4 replicates, we tested 3 resuspension ratios (50, 25, and 17 µL/mg), 2 extraction buffers (with urea or guanidine-hydrochloride), 3 sets of proteases (chymotrypsin, Glu-C, and trypsin/Lys-C), and multiple LC settings. Protein identifications by LC–MS/MS were used to select the best parameters. A total 8738 wheat proteins were identified. The best method was validated on an independent set of 96 cultivars and peptides quantities were normalised using s le weights, an internal standard, and quality controls. Data mining tools found particularly useful to explore the flour proteome are presented (UniProt Retrieve/ID mapping tool, KEGG, AgriGO, REVIGO, and Pathway Tools).
Publisher: Springer Science and Business Media LLC
Date: 30-03-2007
Abstract: Several members of the R2R3-MYB family of transcription factors act as regulators of lignin and phenylpropanoid metabolism during wood formation in angiosperm and gymnosperm plants. The angiosperm Arabidopsis has over one hundred R2R3-MYBs genes however, only a few members of this family have been discovered in gymnosperms. We isolated and characterised full-length cDNAs encoding R2R3-MYB genes from the gymnosperms white spruce, Picea glauca (13 sequences), and loblolly pine, Pinus taeda L. (five sequences). Sequence similarities and phylogenetic analyses placed the spruce and pine sequences in erse subgroups of the large R2R3-MYB family, although several of the sequences clustered closely together. We searched the highly variable C-terminal region of erse plant MYBs for conserved amino acid sequences and identified 20 motifs in the spruce MYBs, nine of which have not previously been reported and three of which are specific to conifers. The number and length of the introns in spruce MYB genes varied significantly, but their positions were well conserved relative to angiosperm MYB genes. Quantitative RTPCR of MYB genes transcript abundance in root and stem tissues revealed erse expression patterns three MYB genes were preferentially expressed in secondary xylem, whereas others were preferentially expressed in phloem or were ubiquitous. The MYB genes expressed in xylem, and three others, were up-regulated in the compression wood of leaning trees within 76 hours of induction. Our survey of 18 conifer R2R3-MYB genes clearly showed a gene family structure similar to that of Arabidopsis. Three of the sequences are likely to play a role in lignin metabolism and/or wood formation in gymnosperm trees, including a close homolog of the loblolly pine PtMYB4 , shown to regulate lignin biosynthesis in transgenic tobacco.
Publisher: Oxford University Press (OUP)
Date: 05-02-2021
Abstract: Legumes form a symbiosis with rhizobia that convert atmospheric nitrogen (N2) to ammonia and provide it to the plant in return for a carbon and nutrient supply. Nodules, developed as part of the symbiosis, harbor rhizobia that are enclosed in a plant-derived symbiosome membrane (SM) to form an organelle-like structure called the symbiosome. In mature nodules exchanges between the symbionts occur across the SM. Here we characterize Yellow Stripe-like 7 (GmYSL7), a Yellow stripe-like family member localized on the SM in soybean (Glycine max) nodules. It is expressed specifically in infected cells with expression peaking soon after nitrogenase becomes active. Unlike most YSL family members, GmYSL7 does not transport metals complexed with phytosiderophores. Rather, it transports oligopeptides of between four and 12 amino acids. Silencing GmYSL7 reduces nitrogenase activity and blocks infected cell development so that symbiosomes contain only a single bacteroid. This indicates the substrate of YSL7 is required for proper nodule development, either by promoting symbiosome development directly or by preventing inhibition of development by the plant. RNAseq of nodules where GmYSL7 was silenced suggests that the plant initiates a defense response against rhizobia with genes encoding proteins involved in amino acid export downregulated and some transcripts associated with metal homeostasis altered. These changes may result from the decrease in nitrogen fixation upon GmYSL7 silencing and suggest that the peptide(s) transported by GmYSL7 monitor the functional state of the bacteroids and regulate nodule metabolism and transport processes accordingly. Further work to identify the physiological substrate for GmYSL7 will allow clarification of this role.
Publisher: Springer Science and Business Media LLC
Date: 12-2019
DOI: 10.1186/S12870-019-2158-3
Abstract: Melatonin ( N -acetyl-5-methoxytryptamine) in plants, regulates shoot and root growth and alleviates environmental stresses. Melatonin and the phyto-hormone auxin are tryptophan-derived compounds. However, it largely remains controversial as to whether melatonin and auxin act through similar or overlapping signalling and regulatory pathways. Here, we have used a promoter-activation study to demonstrate that, unlike auxin (1-naphthalene acetic acid, NAA), melatonin neither induces Direct repeat 5 DR5 expression in Arabidopsis thaliana roots under normal growth conditions nor suppresses the induction of Alternative oxidase 1a AOX1a in leaves upon Antimycin A treatment, both of which are the hallmarks of auxin action. Additionally, comparative global transcriptome analysis conducted on Arabidopsis treated with melatonin or NAA revealed differences in the number and types of differentially expressed genes. Auxin (4.5 μM) altered the expression of a erse and large number of genes whereas melatonin at 5 μM had no significant effect but melatonin at 100 μM had a modest effect on transcriptome compared to solvent-treated control. Interestingly, the prominent category of genes differentially expressed upon exposure to melatonin trended towards biotic stress defence pathways while downregulation of key genes related to photosynthesis was observed. Together these findings indicate that though they are both indolic compounds, melatonin and auxin act through different pathways to alter gene expression in Arabidopsis thaliana . Furthermore, it appears that effects of melatonin enable Arabidopsis thaliana to prioritize biotic stress defence signalling rather than growth. These findings clear the current confusion in the literature regarding the relationship of melatonin and auxin and also have greater implications of utilizing melatonin for improved plant protection.
Publisher: Wiley
Date: 12-07-2020
DOI: 10.1111/NPH.16734
Abstract: Legumes establish symbiotic relationships with soil bacteria (rhizobia), housed in nodules on roots. The plant supplies carbon substrates and other nutrients to the bacteria in exchange for fixed nitrogen. The exchange occurs across a plant‐derived symbiosome membrane (SM), which encloses rhizobia to form a symbiosome. Iron supplied by the plant is crucial for rhizobial enzyme nitrogenase that catalyses nitrogen fixation, but the SM iron transporter has not been identified. We use yeast complementation, real‐time PCR and proteomics to study putative soybean ( Glycine max ) iron transporters GmVTL1a and GmVTL1b and have characterized the role of GmVTL1a using complementation in plant mutants, hairy root transformation and microscopy. GmVTL1a and GmVTL1b are members of the vacuolar iron transporter family and homologous to Lotus japonicus SEN1 (LjSEN1), which is essential for nitrogen fixation. GmVTL1a expression is enhanced in nodule infected cells and both proteins are localized to the SM. GmVTL1a transports iron in yeast and restores nitrogen fixation when expressed in the Ljsen1 mutant. Three GmVTL1a amino acid substitutions that block nitrogen fixation in Ljsen1 plants reduce iron transport in yeast. We conclude GmVTL1a is responsible for transport of iron across the SM to bacteroids and plays a crucial role in the nitrogen‐fixing symbiosis.
Publisher: Elsevier BV
Date: 2011
DOI: 10.1016/J.PLAPHY.2010.09.020
Abstract: Eucalyptus globulus (Labill.) is used for pulp and paper production worldwide. In this report we studied changes in protein expression in one osmotically stressed elite clone widely used in industrial plantations in Spain. High molecular weight polyethylene glycol (PEG) was used as an osmoticum in the growing medium. Roots of rooted cuttings were s led after 3 and 36 h of treatment. Water potential and abscissic acid content were measured in shoot and root apices to characterize the physiological states of the plants. Total soluble proteins from roots were extracted and separated using two-dimensional gel electrophoresis (2-DE). Gels were stained with Coomassie brillant blue for quantitative analysis of protein accumulation. From a total of 406 reproducible spots, 34 were found to be differentially expressed depending on treatment (osmotic versus control condition) and/or stress duration (3 h versus 36 h), and were further characterized by tandem mass spectrometry. Several proteins were reliably identified including adenosine kinase, actin, stress-related proteins as well as proteins associated to cellular processes, among which some residents of the endoplasmic reticulum. This study constitutes the first investigation of the root proteome in this important forest tree genus.
Publisher: Cold Spring Harbor Laboratory
Date: 29-05-2019
DOI: 10.1101/652388
Abstract: An extensive body of evidence from this last decade indicates that melatonin enhances plant resistance to several biotic and abiotic stressors. This has led to an interest in the use of melatonin in agriculture to reduce negative physiological effects from environmental stresses that affect yield and crop quality. However, there are no reports regarding the effects of melatonin on soil microbial communities under abiotic stress, despite the importance of microbes for plant root health and function. Three agricultural soils associated with different land usage histories (pasture, canola or wheat) were placed under abiotic stress by cadmium (100 or 280 mg/kg) or salt (4 or 7 g/kg) and treated with melatonin (0.2 and 4 mg/kg). Automated Ribosomal Intergenic Spacer Analysis (ARISA) was used to generate Operational Taxonomic Units (OTU) for microbial community analysis in each soil. Significant differences in richness (α ersity) and community structures (β ersity) were observed between bacterial and fungal assemblages across all three soils, demonstrating the effect of melatonin on soil microbial communities under abiotic stress. The analysis also indicated that the microbial response to melatonin is governed by the type of soil and history. The effects of melatonin on soil microbes needs to be regarded in potential future agricultural applications.
Location: Australia
Location: Australia
Location: Australia
No related grants have been discovered for Frank Bedon.