35 research outputs found
A comparative meta-proteomic pipeline for the identification of plasmodesmata proteins and regulatory conditions in diverse plant species
Background
A major route for cell-to-cell signalling in plants is mediated by cell wall-embedded pores termed plasmodesmata forming the symplasm. Plasmodesmata regulate the plant development and responses to the environment; however, our understanding of what factors or regulatory cues affect their structure and permeability is still limited. In this paper, a meta-analysis was carried out for the identification of conditions affecting plasmodesmata transport and for the in silico prediction of plasmodesmata proteins in species for which the plasmodesmata proteome has not been experimentally determined.
Results
Using the information obtained from experimental proteomes, an analysis pipeline (named plasmodesmata in silico proteome 1 or PIP1) was developed to rapidly generate candidate plasmodesmata proteomes for 22 plant species. Using the in silico proteomes to interrogate published transcriptomes, gene interaction networks were identified pointing to conditions likely affecting plasmodesmata transport capacity. High salinity, drought and osmotic stress regulate the expression of clusters enriched in genes encoding plasmodesmata proteins, including those involved in the metabolism of the cell wall polysaccharide callose. Experimental determinations showed restriction in the intercellular transport of the symplasmic reporter GFP and enhanced callose deposition in Arabidopsis roots exposed to 75-mM NaCl and 3% PEG (polyethylene glycol). Using PIP1 and transcriptome meta-analyses, candidate plasmodesmata proteins for the legume Medicago truncatula were generated, leading to the identification of Medtr1g073320, a novel receptor-like protein that localises at plasmodesmata. Expression of Medtr1g073320 affects callose deposition and the root response to infection with the soil-borne bacteria rhizobia in the presence of nitrate.
Conclusions
Our study shows that combining proteomic meta-analysis and transcriptomic data can be a valuable tool for the identification of new proteins and regulatory mechanisms affecting plasmodesmata function. We have created the freely accessible pipeline PIP1 as a resource for the screening of experimental proteomes and for the in silico prediction of PD proteins in diverse plant species
Formation of the Stomatal Outer Cuticular Ledge Requires a Guard Cell Wall Proline-Rich Protein
Stomata are formed by a pair of guard cells which have thickened, elastic cell walls to withstand the large increases in turgor pressure that have to be generated to open the pore that they surround. We have characterised FOCL1, a guard cell-expressed, secreted protein with homology to hydroxyproline-rich cell wall proteins. FOCL1-GFP localises to the guard cell outer cuticular ledge and plants lacking FOCL1 produce stomata without a cuticular ledge. Instead the majority of stomatal pores are entirely covered-over by a continuous fusion of the cuticle, and consequently plants have decreased levels of transpiration and display drought tolerance. The focl1 guard cells are larger and less able to reduce the aperture of their stomatal pore in response to closure signals suggesting that the flexibility of guard cell walls is impaired. FOCL1 is also expressed in lateral root initials where it aids lateral root emergence. We propose that FOCL1 acts in these highly specialised cells of the stomata and root to impart cell wall strength at high turgor and/or to facilitate interactions between the cell wall and the cuticle
Recombinant AAV-mediated HSVtk gene transfer with direct intratumoral injections and Tet-On regulation for implanted human breast cancer
BACKGROUND: HSVtk/ganciclovir (GCV) gene therapy has been extensively studied in tumors and relies largely on the gene expression of HSVtk. Most studies, however, have failed to demonstrate any significant benefit of a controlled gene expression strategy in cancer treatment. The Tet-On system is commonly used to regulate gene expression following Dox induction. We have evaluated the antitumor effect of HSVtk/ganciclovir gene therapy under Tet-On regulation by means of adeno-associated virus-2 (AAV-2)-mediated HSVtk gene transfer with direct intratumoral injections in mice bearing breast cancer tumors. METHODS: Recombinant adeno-associated virus-2 (rAAV) was constructed and transduced into MCF-7 cell line. GCV treatment to the rAAV infected MCF-7 cells was performed by MTT assay under the doxycycline (Dox) induction or without Dox induction at a vp (viral particle) number of ≥10(4 )/cell. The virus was administered intratumorally to nude mice that had also received GCV intraperitoneally. The antitumor effects were evaluated by measuring tumor regression and histological analysis. RESULTS: We have demonstrated that GCV treatment to the infected MCF-7 cells under the Dox induction was of more inhibited effects than those without Dox induction at ≥10(4 )vp/cell. In ex vivo experiments, tumor growth of BALB/C nude mice breast cancer was retarded after rAAV-2/HSVtk/Tet-On was injected into the tumors under the Dox induction. Infiltrating cells were also observed in tumors after Dox induction followed by GCV treatment and cells were profoundly damaged. The expression of HSVtk gene in MCF-7 cells and BALB/C nude mice tumors was up-regulated by Tet-On under Dox induction with reverse transcription-PCR (RT-PCR) analysis. CONCLUSION: The antitumor effect of rAAV-mediated HSVtk/GCV gene therapy under the Dox induction with direct intratumoral injections may be a useful treatment for breast cancer and other solid tumors
Ectopic callose deposition into woody biomass modulates the nano-architecture of macrofibrils
Plant biomass plays an increasingly important role in the circular bioeconomy, replacing non-renewable fossil resources. Genetic engineering of this lignocellulosic biomass could benefit biorefinery transformation chains by lowering economic and technological barriers to industrial processing. However, previous efforts have mostly targeted the major constituents of woody biomass: cellulose, hemicellulose and lignin. Here we report the engineering of wood structure through the introduction of callose, a polysaccharide novel to most secondary cell walls. Our multiscale analysis of genetically engineered poplar trees shows that callose deposition modulates cell wall porosity, water and lignin contents and increases the lignin–cellulose distance, ultimately resulting in substantially decreased biomass recalcitrance. We provide a model of the wood cell wall nano-architecture engineered to accommodate the hydrated callose inclusions. Ectopic polymer introduction into biomass manifests in new physico-chemical properties and offers new avenues when considering lignocellulose engineering
Recommended from our members
Fractures caused by north-south compression, eastern Llano Uplift, central Texas : a field guide
"Meeting Gulf Coast Association of Geological Societies, Austin, Texas, October 8, 1994."UT Librarie
Recommended from our members
Geology of Pinto Canyon area, Presidio County, Texas
Pinto Canyon area includes the southern Tierra Vieja Mountains and the northern Chinati Mountains. Lower and middle Permian siltstone, limestone, and chert underlie Comanche limestone and sandstone; Gulf rocks were deposited in the area but were eroded from the crest of a north-trending Laramide anticline. Normal faults that trend N30E cut the anticline before burial by silicic middle Tertiary volcanic strata from several sources. Emplacement of silicic intrusions that range from 1-inch dikes to a 27-square-mile granite-syenite complex followed. Large-scale Basin-and-Range normal faults that trend N5W and N85E displaced the volcanic strata to form the Tierra Vieja, Cuesta del Burro, and Presidio bolson. Gravel, sand, and clay deposited in the bolson are being dissected by tributaries to the Rio Grande. In ascending order the lithostratigraphic sequence comprises the Wolfcamp(?) Alta formation and the Leonard and lower Guadalupe Pinto Canyon formation (new name), both in the Permian system; the Yucca formation, Bluff formation (lower Albian), Cox formation, Finlay formation, Bienevides formation (middle Albian; new name), Loma Plata limestone (upper Albian; new name), Del Rio formation, and Buda formation (Cenomanian?), all in the Comanche series of the Cretaceous system; and the Jeff conglomerate, Vieja formation (basal Oligocene), Shely group (Oligocene?; new name), Moonstone rhyolite (new name), Petan trachyte (new name), and Chinati Mountain group (emended), all in the Tertiary system. Six terrace gravels were mapped in the dissected Presidio bolson, plus alluvium in present arroyos and the Rio Grande floodplain.Geological Science