Expression of a Chimeric Tobacco Peroxidase Gene in Transgenic Tomato Plants (original) (raw)
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Expression of the tobacco anionic peroxidase gene is tissue-specific and developmentally regulated
Plant Molecular Biology, 1998
Transcriptionally regulated expression of tobacco anionic peroxidase was investigated with regard to tissue specificity and developmental regulation. Two tobacco species, Nicotiana sylvestris and Nicotiana tabacum cv. Xanthi, were stably transformed with a gene chimera composed of 3 kb of the tobacco anionic peroxidase promoter, the Escherichia coli ae-glucuronidase (GUS) coding region and the nopaline synthase terminator. Gene expression was regulated spatially and developmentally in all organs, and generally increased with age and maturity of the plant, tissue or organ. In the aerial portions of the plant, GUS activity was strongly expressed in trichomes and epidermis at nearly all developmental stages. In later stages of development, activity was also detected in ground tissue and parenchyma cells associated with vascular tissues. Activity in roots was limited to cortical cells and vascular-associated parenchyma cells. In reproductive tissue, expression was observed in sepals and petals before anthesis, and in all floral organs after anthesis. Expression was never detected in vascular tissue and was poorly correlated with lignification except in the cells surrounding primary xylem and pericyclic fibers in N. sylvestris. These studies suggest that this peroxidase isoenzyme is only limitedly involved in lignification but may be important in plant defense, growth and development.
Characterization of Antisense Transformed Plants Deficient in the Tobacco Anionic Peroxidase
Plant physiology
On the basis of the biological compounds that they metabolize, plant peroxidases have long been implicated in plant growth, cell wall biogenesis, lignification, and host defenses. Transgenic tobacco (Nicotiana tabacum L.) plants that underexpress anionic peroxidase were generated using antisense RNA. The antisense RNA was found to be specific for the anionic isoenzyme and highly effective, reducing endogenous transcript levels and total peroxidase activity by as much as 1600-fold. Antisense-transformed plants appeared normal at initial observation; however, growth studies showed that plants with reduced peroxidase activity grow taller and flower sooner than control plants. In contrast, previously transformed plants overproducing anionic peroxidase were shorter and flowered later than controls. Axillary buds were more developed in antisensetransformed plants and less developed in plants overproducing this enzyme. It was found that the lignin content in leaf, stem, and root was unchanged in antisense-transformed plants, which does not support a role for anionic peroxidase in the lignification of secondary xylem vessels. However, studies of wounded tissue show some reduction in wound-induced deposition of lignin-like polymers. The data support a possible role for tobacco anionic peroxidase in host defenses but not without a reduction in growth potential.
Physiologia Plantarum, 1999
Tomato plants (Lycopersicon esculentum Mill. cv. Pera) were transgenic plants was similar to wild type, although under transformed via Agrobacterium tumefaciens with the binary stress, the plants appeared wilted and the new leaves had a vector pKYLX71 containing a tomato basic peroxidase (EC reduced area and were thicker than wild-type or older trans-1.11.1.7) gene, tpx1, under the control of the cauliflower genic leaves. The root system was underdeveloped in transmosaic virus (CaMV35S) promoter. Transgenic plants showed genic plants, but the rooting ability of the stem was not affected by the overexpression of peroxidase. Finally, the a 2-5-fold increase in the activity of the peroxidase ionically bound to the cell wall, whereas soluble peroxidase activity morphogenetic response of cotyledon and hypocotyl explants remained similar or even lower than wild-type plants. Isoelec-from transgenic plants was evaluated. In the case of cotyledons, the percentage of explants with shoot was not different tric focusing showed the presence of a new isoperoxidase of pI ca 9 in the ionically bound extract. Western blot also showed from wild-type plants. For hypocotyl, one of the transgenic lines showed a 30% reduction in the percentage of shoot the presence of a new band at 41 kDa that was absent in the organogenesis. The results are discussed in relation to the role wild-type extract. A 40-220% increment of lignin content of the leaf was found in transgenic plants. Shoot phenotype of of tpx1 in lignin synthesis.
Expression of a defence-related intercellular barley peroxidase in transgenic tobacco
Plant Science, 1997
(Nicotiuna benthamiana L.) have been transformed with a T-DNA vector construct carrying the cDNA pBH6-301, encoding the major pathogen induced leaf peroxidase (Prx8) of barley. under control of an enhanced CaMV 3% promoter. Progeny from three independent transformants were analyzed genetically. phenotypically and biochemically.
Plant and Cell Physiology, 1999
The Arabidopsis gene APX3 that encodes a putative peroxisomal membrane-bound ascorbate peroxidase was expressed in transgenic tobacco plants. /l.PA'J-expressing lines had substantial levels of APX3 mRNA and protein. The H2O2 can be converted to more reactive toxic molecules, e.g. 'OH, if it is not quickly removed from plant cells. The expression of APX3 in tobacco could protect leaves from oxidative stress damage caused by aminotriazole which inhibits catalase activity that is found mainly in glyoxysomes and peroxisomes and leads to accumulation of H 2 O 2 in those organelles. However, these plants did not show increased protection from oxidative damage caused by paraquat which leads to the production of reactive oxygen species in chloroplasts. Therefore, protection provided by the expression of APX3 seems to be specific against oxidative stress originated from peroxisomes, not from chloroplasts, which is consistent with the hypothesis that APX3 is a peroxisomal membrane-bound antioxidant enzyme.
Protoplasma, 2012
CrPrx and CrPrx1 are class III peroxidases previously cloned and characterized from Catharanthus roseus. CrPrx is known to be apoplastic in nature, while CrPrx1 is targeted to vacuoles. In order to study their role in planta, these two peroxidases were expressed in Nicotiana tabacum. The transformed plants exhibited increased peroxidase activity. Increased oxidative stress tolerance was also observed in transgenics when treated with H(2)O(2) under strong light conditions. However, differential tolerance to salt and dehydration stress was observed during germination of T1 transgenic seeds. Under these stresses, the seed germination of CrPrx-transformed plants and wild-type plants was clearly suppressed, whereas CrPrx1 transgenic lines showed improved germination. CrPrx-transformed lines exhibited better cold tolerance than CrPrx1-transformed lines. These results indicate that vacuolar peroxidase plays an important role in salt and dehydration stress over cell wall-targeted peroxidase, while cell wall-targeted peroxidase renders cold stress tolerance.
Plant Science, 2005
In order to determine the role of ascorbate peroxidase, an antioxidant enzyme, in the cellular responses to oxidative stress and pathogens, transgenic tobacco plants were generated, using the Capsicum annuum ascorbate peroxidase-like 1 gene (CAPOA1), under the control of the CaMV 35S promoter. High levels of CAPOA1 gene expression were observed in the transgenic plants, with a 2-fold increase in total peroxidase activity. The constitutive expression of CAPOA1 in the tobacco exhibited no morphological abnormalities, while significantly increased growth was observed in transgenic plants, as compared to control plants. The CAPOA1-overexpressed plants exhibited increased tolerance to methyl viologen-mediated oxidative stress, and also enhanced resistance to the oomycete pathogen, Phytophthora nicotianae. However, the transgenic plants were not found to be resistant to the bacterial pathogen, Pseudomonas syringae pv. tabaci, but were weakly resistant to Ralstonia solanacearum. Our results suggested that the overproduction of ascorbate peroxidase increased peroxidase activity that enhances active oxygen scavenging system, leading to oxidative stress tolerance and oomycete pathogen resistance.
Plant Science, 1998
In this study, we have investigated the effect of the expression of a cDNA (Shpx6a) encoding a pathogenesis-related peroxidase in the tropical forage legume Stylosanthes humilis on fungal disease resistance in transgenic tobacco and canola plants. Constitutive expression of Shpx6a cDNA was obtained using the 35S CaMV promoter in transgenic tobacco and canola plants and resulted in two to three fold increases in total peroxidase activity using guaiacol as a substrate. The peroxidase encoded by Shpx6a was shown to be located in the apoplast. Inoculation experiments using fungal pathogens Phytophthora parasitica var nicotianae (black shank disease of tobacco) and Leptosphaeria maculans (blackleg disease of canola) showed that expression of Shpx6a peroxidase resulted a small (20-30%) but statistically significant reduction in lesion development in the progeny of transgenic tobacco and canola lines. The enhanced level of tolerance to fungal diseases in both species appears to correlate with the level of peroxidase activity across several lines of transgenic plants. These results provide evidence for a role for the Shpx6a peroxidase in plant defence and suggest that it may be employed as a component of strategies aimed at the engineering of disease resistance.
Induction of a tomato peroxidase gene in vascular tissue
Febs Letters, 1994
Expression of a tomato peroxidase gene that is constitutively expressed only in roots was induced in stems and leaves as a result of mechanical wounding. However, wound-induction of TPXl transcript accumulation in leaves was limited to the mid-rib. No TPXl transcript was detected in the lamina of the leaf after wounding. Peroxidase isozyme studies indicated the presence of a unique basic isoform in stems after wounding.