https://novaprd-lb.newcastle.edu.au/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:41130 Wed 27 Jul 2022 10:35:19 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:171 Wed 22 Mar 2023 17:05:01 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:26914 cyt) of cells trans-differentiating to a transfer cell morphology was tested. This hypothesis was examined using Vicia faba cotyledons. On transferring cotyledons to culture, their adaxial epidermal cells synchronously trans-differentiate to epidermal transfer cells. A polarized and persistent Ca²⁺ signal, generated during epidermal cell trans-differentiation, was found to co-localize with the site of ingrowth wall formation. Dampening Ca²⁺ signal intensity, by withdrawing extracellular Ca²⁺ or blocking Ca²⁺ channel activity, inhibited formation of wall ingrowth papillae. Maintenance of Ca²⁺ signal polarity and persistence depended upon a rapid turnover (minutes) of cytosolic Ca²⁺ by co-operative functioning of plasma membrane Ca²⁺-permeable channels and Ca²⁺-ATPases. Viewed paradermally, and proximal to the cytosol-plasma membrane interface, the Ca²⁺ signal was organized into discrete patches that aligned spatially with clusters of Ca²⁺-permeable channels. Mathematical modelling demonstrated that these patches of cytosolic Ca²⁺ were consistent with inward-directed plumes of elevated [Ca²⁺]_cyt. Plume formation depended upon an alternating distribution of Ca²⁺-permeable channels and Ca²⁺-ATPase clusters. On further inward diffusion, the Ca²⁺ plumes coalesced into a uniform Ca²⁺ signal. Blocking or dispersing the Ca²⁺ plumes inhibited deposition of wall ingrowth papillae, while uniform wall formation remained unaltered. A working model envisages that cytosolic Ca²⁺ plumes define the loci at which wall ingrowth papillae are deposited.]]> Wed 11 Apr 2018 16:31:50 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:31530 Wed 11 Apr 2018 15:47:21 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:6933 Wed 11 Apr 2018 15:29:30 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:19866 Wed 11 Apr 2018 15:06:19 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:19754 Wed 11 Apr 2018 14:07:53 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:20020 Wed 11 Apr 2018 14:02:44 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:26903 Vicia faba cotyledons identified transfer cell specific transcriptomes associated with uniform wall and wall ingrowth deposition. All functional groups of genes examined were expressed before and following transition to a transfer cell fate. What changed were the isoform profiles of expressed genes within functional groups. Genes encoding ethylene and Ca²⁺ signal generation and transduction pathways were enriched during uniform wall construction. Auxin-and reactive oxygen species-related genes dominated during wall ingrowth formation and ABA genes were evenly expressed across ingrowth wall construction. Expression of genes encoding kinesins, formins and villins was consistent with reorganization of cytoskeletal components. Uniform wall and wall ingrowth specific expression of exocyst complex components and SNAREs suggested specific patterns of exocytosis while dynamin mediated endocytotic activity was consistent with establishing wall ingrowth loci. Key regulatory genes of biosynthetic pathways for sphingolipids and sterols were expressed across ingrowth wall construction. Transfer cell specific expression of cellulose synthases was absent. Rather xyloglucan, xylan and pectin biosynthetic genes were selectively expressed during uniform wall construction. More striking was expression of genes encoding enzymes for re-modelling/degradation of cellulose, xyloglucans, pectins and callose. Extensins dominated the cohort of expressed wall structural proteins and particularly so across wall ingrowth development. Ion transporters were selectively expressed throughout ingrowth wall development along with organic nitrogen transporters and a large group of ABC transporters. Sugar transporters were less represented. Conclusions: Pathways regulating signalling and intracellular organization were fine tuned whilst cell wall construction and membrane transporter profiles were altered substantially upon transiting to a transfer cell fate. Each phase of ingrowth wall construction was linked with unique cohorts of expressed genes.]]> Wed 11 Apr 2018 13:16:39 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:14751 Wed 11 Apr 2018 12:47:37 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:26902 2+ levels at loci where wall ingrowth papillae are deposited. The physiological significance of the depletion zones as a mechanism to accommodate the construction of wall ingrowth papillae without compromising maintenance of the plasma membrane-microtubule inter-relationship is discussed.]]> Wed 11 Apr 2018 12:43:42 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:27813 Wed 11 Apr 2018 12:10:22 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:28743 Wed 11 Apr 2018 09:14:14 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:47611 Vicia faba cotyledons. When these cotyledons are placed in culture, their adaxial epidermal cells trans-differentiate to a TC phenotype regulated by auxin, ethylene, extracellular hydrogen peroxide (_apoH₂O₂), and cytosolic Ca²⁺ ([Ca²⁺]_cyt) arranged in series. Staining cultured cotyledons with the sterol-specific dye, Filipin III, detected a polarized sterol-enriched domain in the plasma membrane of their trans-differentiating epidermal transfer cells (ETCs). Ethylene activated sterol biosynthesis while extracellular _apoH₂O₂ directed sterol-enriched vesicles to fuse with the outer periclinal region of the ETC plasma membrane. The sterol-enriched domain was essential for generating the [Ca²⁺]_cyt signal and orchestrating construction of both the uniform wall layer and wall ingrowth papillae. A model is presented outlining how the sterol-enriched plasma membrane domain forms and functions to regulate wall labyrinth assembly.]]> Tue 24 Jan 2023 11:28:41 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:52099 Thu 28 Sep 2023 14:50:07 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:55004 Thu 28 Mar 2024 13:31:01 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:508 Thu 25 Jul 2013 09:10:26 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:228 Thu 25 Jul 2013 09:09:23 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:33601 In planta studies of phloem unloading encounter substantial technical challenges in accessing phloem within a meshwork of vascular/ground tissues. Thus, current understanding of phloem-unloading mechanisms largely has been deduced from indirect experimental measures or modelling. Here we highlight recent advances in understanding phloem unloading mechanisms and identify where important knowledge gaps remain.]]> Thu 22 Nov 2018 16:43:25 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:33602 Sorghum bicolor SUTs SbSUT1 and SbSUT5 were characterized by determining their transport properties heterologously expressed in yeast or Xenopus laevis oocytes, and their in planta cellular and subcellular localization. The plasma membrane-localized SbSUT1 and SbSUT5 exhibited a strong selectivity for Suc and high Suc affinities in X. laevis oocytes at pH 5—SbSUT1, 6.3 ± 0.7 mm, and SbSUT5, 2.4 ± 0.5 mm Suc. The Suc affinity of SbSUT1 was dependent on membrane potential and pH. In contrast, SbSUT5 Suc affinity was independent of membrane potential and pH but supported high transport rates at neutral pH. Suc transport by the tonoplast localized SbSUT4 could not be detected using yeast or X. laevis oocytes. Across internode development, SUTs, other than SbSUT4, were immunolocalized to sieve elements, while for elongating and recently elongated internodes, SUTs also were detected in storage parenchyma cells. We conclude that apoplasmic Suc unloading from de-energized protophloem sieve elements in meristematic zones may be mediated by reversal of SbSUT1 and/or by uniporting SWEETs. Storage parenchyma localized SbSUT1 and SbSUT5 may accumulate Suc from the stem apoplasms of elongating and recently elongated internodes, whereas SbSUT4 may function to release Suc from vacuoles. Transiting from an apoplasmic to symplasmic unloading pathway as the stem matures, SbSUT1 and SbSUT5 increasingly function in Suc retrieval into metaphloem sieve elements to maintain a high turgor to drive symplasmic unloading by bulk flow.]]> Thu 22 Nov 2018 16:43:24 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:31279 Sorghum bicolor, was evaluated during different stages of internode development. Transcript levels and functional properties of selected key transporters were measured, with both cellular and subcellular localization determined.]]> Thu 22 Nov 2018 16:23:38 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:9443 Sat 24 Mar 2018 08:41:33 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:6985 Sat 24 Mar 2018 08:37:50 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:1974 Sat 24 Mar 2018 08:33:16 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:1116 Sat 24 Mar 2018 08:32:07 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:1676 (fructose ≈ glucose)] and hexoses competed with sucrose. Concentration-dependent influxes of all three sugars by excised seed coats could be described by a simple directly proportional relationship between concentration ([S]) and uptake rate (v) in the physiological range of sugar concentrations (v ≈ A.[S]). Alternatively, with the exception of fructose influx by Vicia, all could be fitted to a Michaelis-Menten relationship, as could sucrose uptake by Vicia protoplasts. Apparent K{subscript m} values were high (≈ 100–500 mM) compared with those reported for other systems. Sucrose transport was distinct from glucose and fructose transport in both species. Sugar influx was decreased by p-chloromercuribenzenesulfonic acid, carbonylcyanide m-chlorophenylhydrazone and erythrosin B. These responses are consistent with sugar/H⁺ symport acting to retrieve photoassimilates leaked to the apoplasm during post-sieve element transport within seed coats.]]> Sat 24 Mar 2018 08:30:26 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:1677 Sat 24 Mar 2018 08:30:25 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:1435 Sat 24 Mar 2018 08:28:04 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:1434 Sat 24 Mar 2018 08:28:04 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:16038 Sat 24 Mar 2018 08:21:17 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:13244 Sat 24 Mar 2018 08:16:01 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:11226 Sat 24 Mar 2018 08:11:14 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:10715 Sat 24 Mar 2018 08:08:27 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:20779 Sat 24 Mar 2018 08:05:51 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:19094 Sat 24 Mar 2018 08:05:24 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:19081 Sat 24 Mar 2018 08:05:20 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:21472 Fragaria vesca) and tomato (Solanum lycopersicum) genomes have added to the existing crop databases, and new models are starting to be used in fruit and seed set studies.]]> Sat 24 Mar 2018 08:03:41 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:21810 trans-differentiation events leading to formation of TC ingrowth walls are poorly understood. Vicia faba cotyledons offer a robust experimental model to examine TC induction as, when placed into culture, their adaxial epidermal cells rapidly (h) and synchronously form polarized ingrowth walls accessible for experimental observations. Using this model, we recently reported findings consistent with extracellular hydrogen peroxide, produced through a respiratory burst oxidase homolog/superoxide dismutase pathway, initiating cell wall biosynthetic activity and providing directional information guiding deposition of the polarized uniform wall. Our conclusions rested on observations derived from pharmacological manipulations of hydrogen peroxide production and correlative gene expression data sets. A series of additional studies were undertaken, the results of which verify that extracellular hydrogen peroxide contributes to regulating ingrowth wall formation and is generated by a respiratory burst oxidase homolog/superoxide dismutase pathway.]]> Sat 24 Mar 2018 07:59:23 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:19630 Sat 24 Mar 2018 07:58:15 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:21736 Sat 24 Mar 2018 07:51:52 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:21516 Sat 24 Mar 2018 07:50:28 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:5447 Sat 24 Mar 2018 07:48:13 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:25281 Sat 24 Mar 2018 07:38:13 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:26365 Sorghum bicolor(L.) Moench were deduced from histochemical determinations of cell wall composition and from the relative radial mobilities of fluorescent tracer dyes exiting vascular pipelines. The cell walls of small vascular bundles in source leaves, the predicted site of phloem loading, contained minimal quantities of lignin and suberin. A phloem-loaded symplasmic tracer, carboxyfluorescein, was retained within the collection phloem, indicating symplasmic isolation. Together, these findings suggested that phloem loading in source leaves occurs apoplasmically. Lignin was restricted to the walls of protoxylem elements located in meristematic, elongating and recently elongated regions of the stem. The apoplasmic tracer, 8-hydroxypyrene-1,3,6-trisulfonic acid, moved radially from the transpiration stream, consistent with phloem and storage parenchyma cells being interconnected by an apoplasmic pathway. The major phase of sucrose accumulation in mature stems coincided with heavy lignification and suberisation of sclerenchyma sheath cell walls restricting apoplasmic tracer movement from the phloem to storage parenchyma apoplasms. Phloem unloading at this stage of stem development followed a symplasmic route linking sieve elements and storage parenchyma cells, as confirmed by the phloem-delivered symplasmic tracer, 8-hydroxypyrene-1,3,6-trisulfonic acid, moving radially from the stem phloem.]]> Sat 24 Mar 2018 07:33:08 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:26905 Sat 24 Mar 2018 07:23:35 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:22245 Solanum lycopersicum L.) lines subjected to normal (control) and heat stress temperatures. At the control temperature of 25/20 °C (day/night) the HT line exhibited higher cell wall invertase (CWIN) activity in flowers and young fruits and partitioned more sucrose to fruits but less to vegetative tissues as compared to the HS line, independent of leaf photosynthetic capacity. Upon 2-, 4-, or 24-h exposure to day or night temperatures of 5 °C or more above 25/20 °C, cell wall (CWIN) and vacuolar invertases (VIN), but not sucrose synthase (SuSy), activities in young fruit of the HT line were significantly higher than those of the HS line. The HT line had a higher level of transcript of a CWIN gene, Lin7, in 5-day fruit than the HS line under control and heat stress temperatures. Interestingly, heat induced transcription of an invertase inhibitor gene, INVINH1, but reduced its protein abundance. Transcript levels of LePLDa1, encoding phospholipase D, which degrades cell membranes, was less in the HT line than in the HS line after exposure to heat stress. The data indicate that high invertase activity of, and increased sucrose import into, young tomato fruit could contribute to their heat tolerance through increasing sink strength and sugar signalling activities, possibly regulating a programmed cell death pathway.]]> Sat 24 Mar 2018 07:17:34 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:22243 Vigna unguiculata ssp. sesquipedialis) differing in pod wall and seed growth rates. Pod growth dominates over seed growth in genotype ‘Zhijiang 121’ but not in ‘Zhijiang 282’ in which a ‘bulging pod’ phenotype is apparent from 8 d post-anthesis (dpa) onward. Methods: Seed and pod wall growth rates and degree of pod-bulging were measured in the two genotypes together with assays of activities of sucrose-degrading enzymes and sugar content in pod wall and seed and evaluation of cellular pathways of phloem unloading in seed coat using a symplasmic fluorescent dye, 5(6)-carboxyfluorescein (CF). Key Results: Activities of cell wall, cytoplasmic and vacuolar invertases (CWIN, CIN and VIN) were significantly smaller in pod walls of ‘282’ than in ‘121’ at 10 dpa onwards. Low INV activities were associated with weak pod wall growth of ‘282’. In seed coats, CF was confined within the vasculature in ‘282’ but moved beyond the vasculature in ‘121’, indicating apoplasmic and symplasmic phloem unloading, respectively. Higher CWIN activity in ‘282’ seed coats at 6–8 dpa correlated with high hexose concentration in embryos and enhanced early seed growth. However, CWIN activity in ‘282’ decreased significantly compared with ‘121’ from 10 dpa onwards, coinciding with earlier commencement of nuclei endoreduplication in their embryos. Conclusions: The study shows genotypic differences between ‘bulging pod’ and ‘non-bulging’ phenotypes of asparagus bean in sucrose metabolism in relation to the pathway of phloem unloading in developing seed coats, and to pod and seed growth. Low INV activity in pod wall corresponds to its shortened and weak growth period; by contrast, the apoplasmic path in the seed coat is associated with high CWIN activity and strong early seed growth.]]> Sat 24 Mar 2018 07:17:31 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:23879 Sat 24 Mar 2018 07:13:41 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:24087 Corymbia maculata. The higher rate of fertilizer addition improved seedling establishment of Mimosaceae and the survival of Myrtaceae species. High nutrient treatments increased weed and grass densities, which may have reduced the nutrient benefit for native species. In conclusion, biosolids and the high rate of fertilizer application ameliorated the nitrogen and phosphorus deficiency of spoil to support growth and survival of reintroduced native species. However, potential benefits were attenuated by competition from accompanying weed growth that could be managed by implementing a control program.]]> Sat 24 Mar 2018 07:11:47 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:24712 Sat 24 Mar 2018 07:11:04 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:32463 2+ regulates wall labyrinth assembly. To identify gene cohorts regulated by each signal, a RNA- sequencing study was undertaken using Vicia faba cotyledons. When cotyledons are placed in culture, their adaxial epidermal cells spontaneously undergo trans-differentiation to epidermal TCs (ETCs). Expressed genes encoding proteins central to wall labyrinth formation (signaling, intracellular organization, cell wall) and TC function of nutrient transport were assembled. Transcriptional profiles identified 9,742 annotated ETC-specific differentially expressed genes (DEGs; Log₂fold change > 1; FDR p ≤ 0.05) of which 1,371 belonged to signaling (50%), intracellular organization (27%), cell wall (15%) and nutrient transporters (9%) functional categories. Expression levels of 941 ETC-specific DEGs were found to be sensitive to the known signals regulating ETC trans-differentiation. Significantly, signals acting alone, or in various combinations, impacted similar numbers of ETC-specific DEGs across the four functional gene categories. Amongst the signals acting alone, H₂O₂ exerted most influence affecting expression levels of 56% of the ETC-specific DEGs followed by Ca²⁺ (21%), auxin (18%) and ethylene (5%). The dominance by H₂O₂ was evident across all functional categories, but became more attenuated once trans-differentiation transitioned into WI papillae formation. Amongst the eleven signal combinations, H₂O₂/Ca²⁺ elicited the greatest impact across all functional categories accounting for 20% of the ETC-specific DEG cohort. The relative influence of the other signals acting alone, or in various combinations, varied across the four functional categories and two phases of wall labyrinth construction. These transcriptome data provide a powerful information platform from which to examine signal transduction pathways and how these regulate expression of genes encoding proteins engaged in intracellular organization, cell wall construction and nutrient transport.]]> Mon 23 Sep 2019 12:07:21 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:32294 Vicia faba cotyledon culture system. On transfer of cotyledons to culture, their adaxial epidermal cells spontaneously trans-differentiate to a reticulate architecture comparable to their abaxial epidermal transfer cell counterparts formed in planta. Uniform wall layer construction commenced once adaxial epidermal cell expansion had ceased to overlay the original outer periclinal wall on its inner surface. In contrast to the dense ring-like lattice of cellulose microfibrils in the original primary wall, the uniform wall layer was characterized by a sparsely dispersed array of linear cellulose microfibrils. A re-modeled cortical microtubule array exerted no influence on uniform wall layer formation or on its cellulose microfibril organization. Surprisingly, formation of the uniform wall layer was not dependent upon depositing a cellulose scaffold. In contrast, uniform wall cellulose microfibrils were essential precursors for constructing wall ingrowth papillae. On converging to form wall ingrowth papillae, the cellulose microfibril diameters increased 3-fold. This event correlated with up-regulated differential, and transfer-cell specific, expression of VfCesA3B while transcript levels of other cellulose biosynthetic-related genes linked with primary wall construction were substantially down-regulated.]]> Mon 23 Sep 2019 11:50:11 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:32466 2+ define loci at which WI papillae form in developing adaxial epidermal transfer cells of Vicia faba cotyledons that are induced to trans-differentiate when the cotyledons are placed on culture medium. We evaluated the hypothesis that vesicle trafficking along a Ca²⁺-regulated remodelled actin network is the mechanism that underpins this outcome. Polarized to the outer periclinal cytoplasm, a Ca²⁺-dependent remodelling of long actin bundles into short, thin bundles was found to be essential for assembling WI papillae but not the underlying uniform wall layer. The remodelled actin network directed polarized vesicle trafficking to sites of WI papillae construction, and a pharmacological study indicated that both exo- and endocytosis contributed to assembly of the papillae. Potential candidates responsible for the Ca²⁺-dependent actin remodelling, along with those underpinning polarized exo- and endocyotosis, were identified in a transcriptome RNAseq database generated from the trans-differentiating epidermal cells. Of most significance, endocytosis was controlled by up-regulated expression of a dynamin-like isoform. How a cycle of localized exo- and endocytosis, regulated by Ca²⁺-dependent actin remodelling, assembles WI papillae is discussed.]]> Mon 23 Sep 2019 10:09:31 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:18045 Mon 22 Jun 2015 10:02:57 AEST ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:46193 Vicia faba cotyledons, when placed in culture, undergo a rapid (hours) trans-differentiation to a functional epidermal transfer cell (ETC) phenotype. The trans-differentiation event is controlled by a signalling cascade comprising auxin, ethylene, apoplasmic reactive oxygen species (_apoROS), and cytosolic Ca²⁺. Apoplasmic hydrogen peroxide (_apoH₂O₂) was confirmed as the _apoROS regulating UWL and WI papillae formation. Informed by an ETC-specific transcriptome, a pharmacological approach identified a temporally changing cohort of H₂O₂ biosynthetic enzymes. The cohort contained a respiratory burst oxidase homologue, polyamine oxidase, copper amine oxidase, and a suite of class III peroxidases. Collectively these generated two consecutive bursts in _apoH₂O₂ production. Spatial organization of biosynthetic/catabolic enzymes was deduced from responses to pharmacologically blocking their activities on the cellular and subcellular distribution of _apoH₂O₂. The findings were consistent with catalase activity constraining the _apoH₂O₂ signal to the outer periclinal wall of the ETCs. Strategic positioning of class III peroxidases in this outer domain shaped subcellular _apoH₂O₂ signatures that differed during assembly of the UWL and WI papillae.]]> Mon 14 Nov 2022 11:15:50 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/manager/Repository/uon:41582 Fri 05 Aug 2022 14:51:28 AEST ]]>