Ottó Toldi - Academia.edu (original) (raw)

Papers by Ottó Toldi

vokSaatavana tekijältä MTT:n puutarhatuotannon tutkimuslaitokselt

Plant Cell Reports, Dec 9, 2005

In this paper we describe the first procedure for Agrobacterium tumefaciens-mediated genetic tran... more In this paper we describe the first procedure for Agrobacterium tumefaciens-mediated genetic transformation of the desiccation tolerant plant Ramonda myconi (L.) Rchb. Previously, we reported the establishment of a reliable and effective tissue culture system based on the integrated optimisation of antioxidant and growth regulator composition and the stabilisation of the pH of the culture media by means of a potassium phosphate buffer. This efficient plant regeneration via callus phase provided a basis for the optimisation of the genetic transformation in R. myconi. For gene delivery, both a standard (method A) and a modified protocol (method B) have been applied. Since the latter has previously resulted in successful transformation of another resurrection plant, Craterostigma plantagineum, an identical protocol was utilized in transformation of R. myconi, as this method may prove general for dicotyledonous resurrection plants. On this basis, physical and biochemical key variables in transformation were evaluated such as mechanical microwounding of plant explants and in vitro preinduction of vir genes. While the physical enhancement of bacterial penetration was proved to be essential for successful genetic transformation of R. myconi, an additional two-fold increase in the transformation frequency was obtained when the above physical and biochemical treatments were applied in combination. All R0 and R1 transgenic plants were fertile, and no morphological abnormalities were observed on the whole-plant level.

Journal of the American Society for Horticultural Science, Nov 1, 1997

Plant Science, Jul 1, 1995

... et Giggs) Agnes Bakosa, Miklos Farib, otto Toldib, Miklos Lados*a &amp;quot;Institute... more ... et Giggs) Agnes Bakosa, Miklos Farib, otto Toldib, Miklos Lados*a &amp;quot;Institute for Molecular Genetics, Agricultural Biotechnology Center, H2101 Godollo, PO Box 411, Hungary bInstitute for Plant Sciences, Agricultural Biotechnology Center, H2101 ... [151 SG Strickland, JW Nichol ...

Acta horticulturae, Nov 1, 2006

In recent years, after a short period of stagnation, the importance of plants as a source of phar... more In recent years, after a short period of stagnation, the importance of plants as a source of pharmaceuticals has undergone a resurgence. The reason for this renaissance of plants as a fountain of health and beauty is a sum of many distinct factors. One of these elements is the economic upswing of the Asian countries that has again drawn our attention to the botanical drug market. Traditionally, China is a country where botanical pharma-and nutraceuticals are consumed on a large scale and where these products are fully approved and prescribed, as is also done in many other Asian countries, including Japan and India. A more significant factor contributing to the interest in obtaining new pharmaceuticals from plants is the rapid advancement of molecular technologies. Especially the development of gene transfer methods has facilitated the use of plants as a potential alternative source in the production of pharmaceutical proteins. Recombinant proteins, including vaccines, antibodies, enzymes and regulatory proteins, belong to the rapidly growing sectors in the pharmaceutical industry. The production and expression systems of biologically competitive products should, first of all, be safe and inexpensive to produce. Compared to human and animal cell cultures, plants have several advantages: they are highly scalable, capable of producing biologically active compounds, and free of mammalian viral vectors and pathogens.

Acta Biologica Szegediensis, Sep 5, 2002

We have started to elaborate a general transformation and plant regeneration system for Beta vulg... more We have started to elaborate a general transformation and plant regeneration system for Beta vulgaris L. using combined gene transfer procedure. Three methods were tested: particle bombardment with pure wolfram micro-carriers prior to Agrobacterium treatment, vortexing and infiltration of explants in Agrobacterium suspension, halving of explants. The histochemical analysis of transient and stabile gus-gene expression showed the beneficial effect of explant halving and infiltration in Agrobacterium suspension.

Springer eBooks, Jul 11, 2005

Membranes less attractive to embryos were tested as a replacement for nylon screens to prevent ad... more Membranes less attractive to embryos were tested as a replacement for nylon screens to prevent adherence of somatic embryos, cell clusters and cells to different sites of the bioreactor, a feature considered undesirable in plant cell suspension cultures. The results showed that the loss of embryogenic cell-mass could be halved by using silicone or track membranes. For aeration purposes, these membranes are as satisfactory as nylon screens conventionally used in cell lift impellers.

Acta Agronomica Hungarica, Jun 1, 2006

The fact that production is often unsuccessful even when resistant varieties are selected on the ... more The fact that production is often unsuccessful even when resistant varieties are selected on the basis of the hypersensitive reaction can be attributed to the lack of adequate knowledge on plant disease resistance. In addition to specific plant responses to pathogen species, plants also possess an aspecific defense reaction which, instead of causing rapid tissue destruction, is based on the opposite strategy, protecting the plant against attack by microbes through tissue compaction achieved by cell enlargement and cell division. Genetic analyses carried out in pepper revealed that the general defense reaction was inherited as a monogenic recessive trait (gds). Pathophysiological observations indicate that the stimulus threshold is lower and the reaction rate faster than for specific defense reactions. Biochemical analyses suggest that, unlike plants exhibiting rapid tissue destruction, plants containing the gds gene do not require an oxidative burst elicited by hydrogen peroxide to stimulate the defense m...

Acta Agronomica Hungarica, Mar 1, 2007

The purpose of this work was to further investigate the regulatory interplay between pyrophosphat... more The purpose of this work was to further investigate the regulatory interplay between pyrophosphate:fructose 6-phosphate 1-phosphotransferase (PFP) and its positive effector, fructose 2,6-bisphosphate (Fru-2,6-P2), in the storage organs of cold- and drought-stressed plants. Since there is no detectable cytoplasmic fructose-1,6-bisphosphatase (cytFBPase) activity in the taproots of carrot plants, PFP is the only enzyme that can replace its function when stored starch is converted to transportable sucrose. The working hypothesis was that PFP is likely to be involved in the mobilisation of energy reserves and might have a special role in storage organs such as carrot taproots upon stress. Both cold and drought stress resulted in a marked increase in the endogenous Fru-2,6-P2levels. It is suggested that the significant changes in photosynthate allocation are the direct results of the stimulation of PFP activity by elevated Fru-2,6-P2levels. PFP stimulated by Fru-2,6-P2operated in the gluconeogenic direction in the taproots of stressed carrot plants, whereas the glycolytic direction was dominant in the non-stressed controls. This suggests that the metabolic status determining the net activity of PFP depends on the physiological stress situation, making PFP an important sensor of environmental changes. The experimental data indicated that PFP is involved in the mobilisation of energy reserves during unfavourable environmental changes by promoting the re-synthesis of transportable sucrose in taproots.

Acta Biologica Szegediensis, 2006

The purpose of this work was to further investigate the regulatory interplay between pyrophosphat... more The purpose of this work was to further investigate the regulatory interplay between pyrophosphate:fructose 6-phosphate 1-phosphotransferase (PFP) and its positive effector fuctose 2,6-bisphosphate (Fru-2,6-P 2) in heterotrophic tissues. Transformation of carrot plants (Daucus carota L. cv. Nantes Duke) with mutated mammalian 6-phosphofructo-2-kinase / fructose 2,6-bisphosphatase gene (6-PF-2-K/ Fru 2,6-P 2 ase) produced carrot taproots which possessed between 163% and 410% of the Fru-2,6-P 2 levels observed in wild-type taproots. Besides Fru-2,6-P 2 , the levels of 3-phosphoglycerate (3PGA) and hexose phosphates (hexose-P) showed the most significant alterations. Transgenic taproots possessed a marked increase in PFP activity that was accompanied by high 3PGA / hexose-P ratios under normal physiological conditions. Interestingly, 3PGA / hexose-P ratios became significantly lower in taproots exposed to drough or cold without any decrease in PFP activity. We suggested that changes in 3PGA / hexose-P ratios are a direct result of stimulation of PFP activity by the elevated Fru-2,6-P 2 levels. The Fru-2,6-P 2-stimulated PFP operates in the glyconeogenic direction in the taproots of stressed carrot plants, whereas the glycolytic direction dominates in the non-stressed controls. This suggests that the metabolic status determining the net activity of PFP depends on the physiological stress situations and such, PFP is an important sensor of the environmental changes. Likely that PFP is also involved in mobilisation of energy reserves upon unfavourable environmental changes by promoting the re-synthesis of transportable sucrose through gluconeogenesis from accumulated starch in taproots.

Romanian Biotechnological Letters, Mar 1, 2010

A majority of plants possess stages in their life cycle at which specific tissues, mainly compone... more A majority of plants possess stages in their life cycle at which specific tissues, mainly components of reproductive organs (mature pollen, seed) and dormant buds, can survive severe water loss. What is remarkable about resurrection plants is the ability of vegetative tissues (root, shoot, stem, leaves) to tolerate dehydration of the tissues and then return as functional units on rehydration. This phenomenon made resurrection plants exciting targets for molecular analysis of the poikilohydric ability and drought tolerance. Large-scale isolation of drought stress associated genes with unknown biological roles requires thorough functional analysis. Despite of the genetic and physiological complexity of desiccation tolerance, there are already examples where outcomes of targeted studies in resurrection plants are going to be directly utilized to engineer crop plants genetically. Here we show that conventional genetic transformation techniques, via in vitro plant regeneration systems, still represent an unavoidable part of the high-throughput technology chain of molecular breeding.

Plant Growth Regulation, Sep 1, 2005

The purpose of this study was to search for physiological parameters that provide an early indica... more The purpose of this study was to search for physiological parameters that provide an early indication of the morphogenetic response of leaf disc explants to different tissue culture-level manipulations in order to design an accelerated optimisation process for this technology. Tobacco (Nicotiana tabacum L. cv. Samsun) was chosen as model in our studies, because this is still one of the

Plant Cell Reports, Jul 1, 2002

Procedures previously established for plant regeneration and Agrobacterium tumefaciens-mediated g... more Procedures previously established for plant regeneration and Agrobacterium tumefaciens-mediated genetic transformation of the desiccation-tolerant plant, Craterostigma plantagineum, have been further developed. A highly effective tissue culture system was established based on the integrated optimisation of antioxidant and growth regulator composition and the stabilisation of the pH of the culture media by means of a potassium phosphate buffer. The undesirable hyperhydricity

vokSaatavana tekijältä MTT:n puutarhatuotannon tutkimuslaitokselt

Plant Cell Reports, Dec 9, 2005

Journal of the American Society for Horticultural Science, Nov 1, 1997

Plant Science, Jul 1, 1995

Acta horticulturae, Nov 1, 2006

Acta Biologica Szegediensis, Sep 5, 2002

Springer eBooks, Jul 11, 2005

Acta Agronomica Hungarica, Jun 1, 2006

Acta Agronomica Hungarica, Mar 1, 2007

Acta Biologica Szegediensis, 2006

The purpose of this work was to further investigate the regulatory interplay between pyrophosphat... more The purpose of this work was to further investigate the regulatory interplay between pyrophosphate:fructose 6-phosphate 1-phosphotransferase (PFP) and its positive effector fuctose 2,6-bisphosphate (Fru-2,6-P 2) in heterotrophic tissues. Transformation of carrot plants (Daucus carota L. cv. Nantes Duke) with mutated mammalian 6-phosphofructo-2-kinase / fructose 2,6-bisphosphatase gene (6-PF-2-K/ Fru 2,6-P 2 ase) produced carrot taproots which possessed between 163% and 410% of the Fru-2,6-P 2 levels observed in wild-type taproots. Besides Fru-2,6-P 2 , the levels of 3-phosphoglycerate (3PGA) and hexose phosphates (hexose-P) showed the most significant alterations. Transgenic taproots possessed a marked increase in PFP activity that was accompanied by high 3PGA / hexose-P ratios under normal physiological conditions. Interestingly, 3PGA / hexose-P ratios became significantly lower in taproots exposed to drough or cold without any decrease in PFP activity. We suggested that changes in 3PGA / hexose-P ratios are a direct result of stimulation of PFP activity by the elevated Fru-2,6-P 2 levels. The Fru-2,6-P 2-stimulated PFP operates in the glyconeogenic direction in the taproots of stressed carrot plants, whereas the glycolytic direction dominates in the non-stressed controls. This suggests that the metabolic status determining the net activity of PFP depends on the physiological stress situations and such, PFP is an important sensor of the environmental changes. Likely that PFP is also involved in mobilisation of energy reserves upon unfavourable environmental changes by promoting the re-synthesis of transportable sucrose through gluconeogenesis from accumulated starch in taproots.

Romanian Biotechnological Letters, Mar 1, 2010

Plant Growth Regulation, Sep 1, 2005

Plant Cell Reports, Jul 1, 2002

O.Toldi, S.Sorvari, K.Tóth-Lencsés, L.Kovács, A.Kerekes, Á.Mendel, Zs.Tóth, G.Gyulai: Life Histor... more O.Toldi, S.Sorvari, K.Tóth-Lencsés, L.Kovács, A.Kerekes, Á.Mendel, Zs.Tóth, G.Gyulai: Life History Barcoding of Daucus carota. In: M.Ajmal Ali, G.Gyulai, F.Al-Hemaid (eds) Plant DNA Barcoding and Phylogenetics, Lambert Academic Publishing, Saarbrücken, Germany, pp. 227-240.

Over the last few years there have been major advances in applying the use of plant tissue cultur... more Over the last few years there have been major advances in applying the use of plant tissue culture to the study of poikilohydric or resurrection plants. The three main species (Craterostigma plantagineum, Haberlea rhodopensis and Ramonda myconi) which have been studied as model resurrection plants have now been introduced into tissue culture and two of them (C. plantagineum and R. myconi) were successfully transformed with marker genes , Tóth et al. 2005. A large number of genes have been identified which may play a role in underpinning the ability of the plant tissues to survive severe tissue water loss. There have been a number of elegant experiments which have used tissue culture to study metabolism in resurrection plants. The time is now ripe for the large scale molecular analysis of the poikilohydric ability of these plants using tissue culture as a major tool to drive research forward. Large-scale isolation of drought stress associated genes with unknown biological roles requires functional analysis. Here we show that conventional genetic transformation techniques, via in vitro plant regeneration systems, still represent an unavoidable part of the high-throughput functional genetics analyses. Similarities and differences in tissue culturing and genetic transformation of these resurrection plants, as a consequence of their common physiological specialisation, are summarized, and future prospects of advances in this area of research are discussed.

In contrast to most tropical orchids the European temperate orchids have proven to be very diffic... more In contrast to most tropical orchids the European temperate orchids have proven to be very difficult to grow in soil and in tissue culture. The plants can be grown in tissue culture and then can be transferred to soil but require up to 5 years to attain a flowering size. In addition there are no propagation methods for many species of these orchids. This long time investment has meant commercial growing of these plants is very rare. In this work we report the tissue culturing of the green winged orchid and the transfer to soil. Once in soil experiments have been performed on the plants whereby the nutrients and growth regulators used in tissue culture have been applied in the soil. Using the optimized methods quoted in this work it has been possible to accelerate growth in the plants such that they flower within 2 years of sowing seeds and in addition can be forced to propagate. This work could provide a powerful tool for orchid conservation and for the commercialization of these rare and unusual plants.

isBn 978-963-269-200-5 tipográfia és nyomdai előkészítés:

"Competitiveness is how a nation manages the totality of its resources and competencies to increa... more "Competitiveness is how a nation manages the totality of its resources and competencies to increase the prosperity of its people." (2008, Professor Stéphane Garelli, IMD World Competitiveness Yearbook) "A nation-state is energy secure to the degree that fuel and energy services are available to ensure: a) survival of the nation, b) protection of national welfare, and c) minimization of risks associated with supply and use of fuel and energy services. The five dimensions of energy security include energy supply, economic, technological, environmental, social and cultural, and military/security dimensions."

co-author Under the United Nations Framework, Convention on Climate Change, Ministry of Nationa... more co-author

Under the United Nations Framework, Convention on Climate Change, Ministry of National Development, Department for Climate Policy

Impresszum megjelenés éve: 2012 Kiadó: Nemzeti Fejlesztési minisztérium Készült: 600 példányban G... more Impresszum megjelenés éve: 2012 Kiadó: Nemzeti Fejlesztési minisztérium Készült: 600 példányban Grafikai tervezés: Lounge Design Nyomda:prospektus Nyomda az mVm zrt támogatásával IsBN 978-963-89328-1-5 Nemzeti energiastratégia 2030 Nemzeti Fejlesztési minisztérium A képek az mVm-tôl származnak. 5 4 "A versenyképesség a nemzet azon képessége, ahogy forrásainak és szakértelmének összességét kezeli az állampolgárai boldogulása érdekében."