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János Pauk

Bio: János Pauk is an academic researcher from Szent István University. The author has contributed to research in topics: Doubled haploidy & Microspore. The author has an hindex of 16, co-authored 52 publications receiving 579 citations.


Papers
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Journal ArticleDOI
TL;DR: Culture conditions for triticale (X Triticosecale Wittmack) androgenesis were studied using microspore culture and Adventitious embryogenesis was observed during in vitro development of triticalse microspores.
Abstract: Culture conditions for triticale (X Triticosecale Wittmack) androgenesis were studied using microspore culture Sporophytic development of isolated triticale microspores in culture is described in five winter hexaploid triticale genotypes Microspores were isolated using a microblendor, and embryogenesis was induced in modified 190-2 medium both in the presence and absence of growth regulators The highest induction of microspore embryogenesis was obtained in a growth regulator-free medium Adventitious embryogenesis was observed during in vitro development of triticale microspores Albino and green plantlets were regenerated from embryo-like structures More than 50% of regenerants were albino In total, 126 green plantlets were produced, transplanted and established in soil Cytological evidence revealed that 90% of the transplanted regenerants were haploid

61 citations

Journal ArticleDOI
TL;DR: In this study, the phenomenon of albinism and genotype dependency did not hinder the production of more than five thousand green plantlets each year and anther culture proved to be an efficient method in winter wheat breeding programmes with lower costs than alternative technologies.
Abstract: The efficiency of our anther culture protocol was tested with high- and low-responding genotypes, ‘Svilena’ and ‘Berengar’, and 93 F1 winter wheat crosses in 2010 and 2011. Based on data for these genotypes, the effect of genotype influenced the number of embryo-like structures, regenerated plantlets and green plantlets, while the number of albino plantlets was affected by genotype, year and environmental factors. Although genotype also influenced the production of green plantlets from breeding crosses, with green plantlets per 100 anthers ranging from 0.04 to 28.67, the average regeneration rate over all crosses was 5.3 green plantlets/100 anthers, which resulted in a total of 11 416 well-rooted green plantlets. The survival rate of green plantlets following acclimatization was 97.21% in 2010 and 96.34% in 2011. In this study, the phenomenon of albinism and genotype dependency did not hinder the production of more than five thousand green plantlets each year. In our experiments, anther culture proved to be an efficient method in winter wheat breeding programmes with lower costs than alternative technologies.

47 citations

Journal ArticleDOI
TL;DR: The anther culture protocol described in this study is an efficient tool for the production of microspore-derived green plantlets in triticale.
Abstract: Two haploid induction media (190-0 and W14mi) were tested in isolated microspore culture of two triticale (X Triticosecale Wittmack) genotypes. The W14mi medium proved superior for the production of green plantlets in both genotypes. This basic medium (W14) was used to compare two doubled haploid production methods (isolated microspore culture and anther culture) with the same genotypes. The induction of androgenesis was more effective in isolated microspore culture than in anther culture. The number of embryo-like structures was 9.2 times higher in microspore culture (511.0/100 anthers) compared to anther culture (55.5/100 anthers) and the number of regenerant plantlets was also 3.4 times higher (anther culture—20.15/100 anthers; isolated microspore culture—67.6/100 anthers). However, the regenerant plantlets from isolated microspore culture were mainly albinos while predominantly green plantlets were regenerated from anther culture. The production of green plantlets from anther culture (16.8/100 anthers) was 2.9 times higher than from isolated microspore culture (5.8/100 anthers). The efficiency of anther culture was tested with eight winter triticale genotypes. The phenomenon of albinism did not hinder the green plant production in anther culture. Mean green plantlet production was 10.87/100 anthers. This value was two times higher than the number of albinos (5.01/100 anthers) and higher than previously published reports. The anther culture protocol described in this study is an efficient tool for the production of microspore-derived green plantlets in triticale.

39 citations

Journal ArticleDOI
TL;DR: The data confirmed the existence of heterosis for RA and CI in F2 populations and demonstrated a new plant regeneration system, found to be significantly better than the C-17 in the number of responsive anthers (RA) and calli induced (CI) at the 1 % and 0.1 % level.
Abstract: The main goals of the wheat androgenesis experiment were to study the main phenomena of in vitro androgenesis in anther culture of F2 populations (10) and their parents (6), to compare the usage of P-4 and C-17 media for the formation of embryo/callus and to demonstrate a new plant regeneration system. The P-4 induction medium was found to be significantly better than the C-17 in the number of responsive anthers (RA) and calli induced (CI) at the 1 % and 0.1 % level, respectively. Genotypic effect was evident in both RA and CI. The yields of F2 populations in RA and CI were significantly higher than those of their parents regarding both media. The data confirmed the existence of heterosis for RA and CI in F2 populations. The ratio of green/albino plant regeneration was more favourable in the C-17 derived embryo/calli than in the P-4 derived ones. The frequency of plantlet regeneration was enhanced in the group of unresponsive calli by the application of the multiple-step regeneration system. In this system the calli lacking well developed morphogenic structure were transferred to a new regeneration medium, containing a higher concentration of the same cytokinin, other cytokinin or basic medium, before the occurrence of irreversible changes in their physiology.

38 citations

Journal ArticleDOI
TL;DR: Members of the aldo–keto reductase family including aldose reductases are involved in antioxidant defense by metabolizing a wide range of lipid peroxidation-derived cytotoxic compounds and these plants consequently exhibit 1.5–4.3 times higher detoxification activity for the aldehyde substrate.
Abstract: Members of the aldo–keto reductase family including aldose reductases are involved in antioxidant defense by metabolizing a wide range of lipid peroxidation-derived cytotoxic compounds. Therefore, we produced transgenic wheat genotypes over-expressing the cDNA of alfalfa aldose reductase gene. These plants consequently exhibit 1.5–4.3 times higher detoxification activity for the aldehyde substrate. Permanent drought stress was generated in the greenhouse by growing wheat plants in soil with 20 % water capacity. The control and stressed plants were monitored by a semi automatic phenotyping platform providing computer-controlled watering, digital and thermal imaging. Calculation of biomass values was based on the correlation (R 2 = 0.7556) between fresh weight and green pixel-based shoot surface area. The green biomass production by plants of the three transgenic lines was 12–26–41 % higher than the non-transgenic plants’ grown under water limitation. Thermal imaging of stressed non-transgenic plants indicated an elevation in the leaf temperature. The thermal status of transformants was similar at both normal and suboptimal water regime. In drought, the transgenic plants used more water during the growing season. The described phenotyping platform provided a comprehensive data set demonstrating the improved physiological condition of the drought stressed transgenic wheat plants in the vegetative growth phase. In soil with reduced water capacity two transgenic genotypes showed higher seed weight per plant than the control non-transgenic one. Limitation of greenhouse-based phenotyping in analysis of yield potential is discussed.

38 citations


Cited by
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Journal ArticleDOI
TL;DR: The technology of insect-resistant transgenic plants is expanding very rapidly, with considerable research activity in both the private and public sectors, but the use of resistance genes from other microorganisms and animals has so far been limited.

379 citations

Journal ArticleDOI
TL;DR: According to the results, the appearance of new isozyme bands under drought stress con - ditions may be used as a biochemical marker to differentiate drought tolerant cultivars under drought Stress.
Abstract: The study was undertaken to identify the responses of antioxidant enzyme activities and their isozyme patterns in seedlings of 10 oilseed rape ( Brassica napus L.) cultivars under drought stress conditions. Plants were grown under three irrigation regimes (FC; field capacity, 60% FC and 30% FC) in a greenhouse. Drought stress preferentially enhanced the activities of superoxide dismutase (SOD) and guaiacol peroxidase (POD) whereas it decreased catalase (CAT) activity. Licord with the highest level of enzyme activity under both optimum and limited irrigation regimes is reported as the most tolerant cultivar. Whereas Hyola 308 and Okapy, having the lowest enzymes activities, are mentioned as cultivars sensitive to drought stress. The native polyacrylamide gel electrophoresis (PAGE) analysis detected eight SOD isozymes. Oilseed rape leaves contained three isoforms of Mn-SOD and five isoforms of Cu/Zn-SOD. The expression of Mn-SOD was preferentially enhanced by drought stress. Five POD isoforms were detected in oilseed rape leaves. The intensities of POD-4 and -5 were enhanced under drought stress. According to the results, the appearance of new isozyme bands under drought stress con - ditions may be used as a biochemical marker to differentiate drought tolerant cultivars under drought stress.

294 citations

Journal ArticleDOI
TL;DR: It is concluded that leaf protein profiles could be useful marker in the studies of genetic variation and classification of adapted cultivars under control and stress conditions.
Abstract: With a view to understanding the traits which can be used as a quick criteria for drought tolerance, field and laboratory experiments were used to evaluate nine wheat (Triticum aestivum L.) genotypes; seven local varieties with two introduced genotypes from International Center for Agricultural Research in the Dry Areas (ICARDA). The field experiment was grown under two water regimes (stress and non stress treatments). The stress treatment induced by withholding irrigation after emergence and giving two supplementary irrigations, one after 60 days post-sowing and the other after 90 days post-sowing and non stress (well-watered). Combined analysis of variance over two seasons showed highly significant differences among wheat genotypes in all the studied traits and water stress decreased them significantly. The superior genotypes 1,2 and 6 which gave higher relative water content (RWC) accumulated more free proline (Pro) and had lower drought susceptibility index (S) values, whereas genotypes 3, 4 and 9 had the lowest RWC, Pro accumulation and had the highest S values. Indicating that accumulated Pro acts as a compatible solute regulating and reducing water loss from the cell during episodes of water deficit. High RWC and Pro over-accumulation were recognized as beneficial drought tolerance indicators and may be used as selection criteria in wheat breeding program. Effects of drought stress in laboratory experiment were induced by polyethylene glycol (PEG) (0, 15 and 25%, with three replicates) and applied on germination of wheat genotypes seeds. The PEG induced a drop in the shoot, root biomass and coleoptiles length which was the greatest in genotypes 3, 4 and 9, while the decrease in genotypes 1, 2 and 6 was little under the various levels from PEG. The variability of leafproteins was analyzed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). It is concluded that leaf protein profiles could be useful marker in the studies of genetic variation and classification of adapted cultivars under control and stress conditions.

245 citations

Journal ArticleDOI
TL;DR: An overview of the basic isolated microspore culture protocol is provided with an emphasis on recent progress in several crop species.
Abstract: An isolated microspore culture provides an excellent system for the study of microspore induction and embryogenesis, provides a platform for an ever-increasing array of molecular studies, and can produce doubled haploid (DH) plants, which are used to accelerate plant-breeding programs. Moreover, isolated microspore cultures have several advantages over anther culture, wherein presence of the anther walls can lead to the development of diploid, somatic calli and plants. Although protocols for isolated microspore culture vary from laboratory to laboratory, the basic steps of growing donor plants, harvesting floral organs, isolating microspores, culturing and inducing microspores, regenerating embryos, and doubling the chromosomes, remain the same. Over the past few years, a large proportion of the research reports on isolated microspore culture have focused on cereal and Brassica species. For some of these species, isolated microspore culture protocols are well established and routinely used in laboratories around the world for developing new varieties, as well as for basic research in areas such as genomics, gene expression, and genetic mapping. Although these species are considered highly responsive to microspore culture, improvements in efficiency are still being made. However, with many species, isolated microspore culture is simply not yet efficient enough at producing DH plants to be cost-effective for breeding programs. There has been a recent resurgence of haploidy research with response being reported in some species once considered recalcitrant. Future research programs aimed at elucidating pathways involved in microspore induction and embryogenesis will be of benefit, as will novel approaches to improve the efficiency of microspore culture for DH production. With many species, anther culture has proven to be more effective than isolated microspore culture, necessitating more research to clarify the contribution of the anther wall to embryogenesis. The development of molecular markers for use in determining the gametic origin of regenerated plants, irrespective of their ploidy, would also be beneficial. In this review, we aim to provide an overview of the basic isolated microspore culture protocol with an emphasis on recent progress in several crop species.

226 citations

Journal ArticleDOI
TL;DR: An overview of various stresses and mechanisms of action of these stresses in inducing microspore embryogenesis is given and whether these stresses are effective in a wider range of species is seen.
Abstract: Microspore embryogenesis is the most commonly used method to produce doubled haploids. It is based on the ability of a single haploid cell, the microspore, to de-differentiate and regenerate into a whole plant after being exposed to stresses, such as low or high temperatures, carbon starvation and colchicine. Some stresses such as temperature treatments and carbon starvation have been used with success in many plant species, whereas others such as colchicine had limited application in a few species. Reports on the application of whole plant treatments with feminizing agents on inflorescences and buds are scarce. Furthermore, the technical means to apply some stresses such as γ-irradiation are not readily available. Recently, novel stresses such as pH, inducer chemicals, carrageenan oligosaccharides and heavy metals were reported to induce microspore embryogenesis. It remains to be seen, however, whether these stresses are effective in a wider range of species. Finally, pretreatment of cultured cells with high concentrations of 2,4-D efficiently induces somatic embryogenesis in several species (carrot, alfalfa). However, reports on the use of this particular chemical stress are not available in microspore embryogenesis. The paper presented here gives an overview of various stresses and mechanisms of action of these stresses in inducing microspore embryogenesis.

192 citations