https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:47541 Wed 24 Jan 2024 14:39:30 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48013 Wed 15 Feb 2023 09:38:01 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:27948 Gossypium hirsutum) endoglucanase, GhKOR1, plays significant roles in endosperm and embryo development. RNA interference (RNAi)- and co-suppression-mediated down-regulation of GhKOR1 resulted in smaller filial tissue and reduced seed weight, which were characterized by disrupted endosperm cellularization and delayed embryo development, leading to a delayed germination and a weak growth of seedlings early in development. The transgenic seeds exhibited fewer and smaller endosperm cells with irregular and brittle cell walls, and their embryos developed only to the globular stage at 10 days post-anthesis (DPA) when the wild-type endosperm has become highly cellularized and the embryo has progressed to the heart stage. The transgenic seed also displayed a significant reduction of callose in the seed coat transfer cells and reduced cellulose content both in the seed coat and in mature fibres. These findings demonstrate that GhKOR1 is required for the developmental of both seed filial and maternal tissues and the establishment of seedling vigour.]]> Wed 11 Apr 2018 17:07:07 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:5536 Wed 11 Apr 2018 16:35:30 AEST ]]> https://nova.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://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:8254 Wed 11 Apr 2018 16:05:39 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:31530 Wed 11 Apr 2018 15:47:21 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:6933 Wed 11 Apr 2018 15:29:30 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:31556 GmCYP78A5, in transgenic soybean resulted in increased seed size and seed weight. Together, these analyses identified a large number of potential key regulators controlling soybean seed set, seed size, and, consequently, yield potential, thereby providing new insights into the molecular networks underlying soybean seed development.]]> Wed 11 Apr 2018 13:59:38 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:27813 Wed 11 Apr 2018 12:10:22 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:9646 Wed 11 Apr 2018 10:22:43 AEST ]]> https://nova.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://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:40858 Tue 19 Jul 2022 13:49:20 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48341 Thlaspi caerulescens, and in a cultivar-specific manner by water stress in Brassica. This latter observation provides an experimental platform to probe phi thickening function, and to identify genetic pathways responsible for their formation. These pathways might be expected to differ from those involved in secondary wall formation in xylem, since phi thickening deposition in not linked to programmed cell death.]]> Tue 14 Mar 2023 17:29:49 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51304 Thu 31 Aug 2023 14:21:03 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46517 Thu 24 Nov 2022 16:04:25 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46834 Thu 01 Dec 2022 14:40:34 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:1974 Sat 24 Mar 2018 08:33:16 AEDT ]]> https://nova.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://nova.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://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:18695 Mon 20 Jul 2015 17:48:33 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:51787 Mon 18 Sep 2023 15:18:36 AEST ]]> https://nova.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://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:50817 Fri 18 Aug 2023 11:09:34 AEST ]]>