12 research outputs found
Role of some N-containing compounds in chilling tolerance of maize
The paper reports on the effect of low temperature on the synthesis of a number of N-containing compounds in five inbred maize lines with different degrees of chilling tolerance. The compounds analysed are used as stress markers on the basis of their response to abiotic stress factors. The aim of the experiments was to obtain a better understanding of the role of these compounds in maize chilling tolerance. The results indicate that changes of various magnitudes occur in the quantities of putrescine, agmatine, glycine-betain and proline as the result of chilling treatment. The quantitative changes are correlated with the chilling tolerance of the given inbred maize lines. The alternative pathway of polyamine synthesis plays a substantial role in the development of the defence mechanism against low temperature
Effect of salt stress on the endogenous salicylic acid content in maize (Zea mays L.) plants
Two-week-old maize plants were treated with 50 or 100 mM NaCl for seven days. Leaves and roots were collected for measurements on salicylic acid and antioxidant enzyme activity on the 1st, 3rd and 7th days of treatment and after four days of recovery. The quantum yield of photosystem II decreased after 7 days in maize plants treated with 100 mM NaCl. There were no changes in the catalase and ascorbate peroxidase activity. The glutathione-S-transferase, glutathione reductase and guaiacol peroxidase activities increased. There were no changes in the level of endogenous free and bound salicylic acid. The free o-hydroxy-cinnamic acid (oHCA) content increased after 7 days in the leaves, while the bound oHCA level increased after 4 days of recovery. It has been concluded that oHCA may play an important role in stress processes
Alacsony hőmérsékleti stressztolerancia és antioxidáns aktivitás közti kapcsolat vizsgálata gabonaféléknél = Investigation of the connection between tolerance to low temperature stress and antioxidant activity in cereals
A kutatási munka cĂ©lja a gabonafĂ©lĂ©k stressztűrĹ‘ kĂ©pessĂ©gĂ©nek kialakĂtásában szerepet játszĂł szabályozási folyamatok jobb megismerĂ©se volt, kĂĽlönös tekintettel a reaktĂv oxigĂ©nformák mennyisĂ©gĂ©nek szabályozását vĂ©gzĹ‘ antioxidáns rendszerekre. Több gazdasági növĂ©ny, elsĹ‘sorban kukorica Ă©s bĂşza esetĂ©ben jellemeztĂĽk az antioxidáns enzimrendszerek hozzájárulását abiotikus stresszfaktorok elleni vĂ©delemben. Kimutattuk, hogy a kĂĽlönbözĹ‘ gabonafajok eltĂ©rĹ‘ stratĂ©giákat dolgoztak ki a reaktĂv oxigĂ©nformák mennyisĂ©gĂ©nek szabályozásához. Igazoltuk a fĂ©ny szerepĂ©t a bĂşza maximális fagyállĂłságának kialakulásában. Ehhez kapcsolĂłdĂłan bemutattuk a ciklikus elektrontranszportlánc, egyes antioxidánsok, a szalicilsav-metabolizmus, valamint a membránlipidek alakulását eltĂ©rĹ‘ fĂ©nyviszonyok melletti alacsony hĹ‘mĂ©rsĂ©kleti edzĂ©s során. EredmĂ©nyeink azt mutatják, hogy a szalicilsavfĂĽggĹ‘ jelátviteli utak szerepĂ©nek tanulmányozásakor nemcsak magára a szalicilsavra, hanem egyes prekurzorainak a változásaira is figyelemmel kell lenni. Mindemellett bizonyĂtottuk, hogy intakt levelekben az egy elektronátmenetet megengedĹ‘ fĂ©nyfelvillanás általi gerjesztĂ©s egy összetett termolumineszcencia sávot eredmĂ©nyez, melynek magasabb hĹ‘mĂ©rsĂ©kleti (40 °C körĂĽli) komponense egy AG-sáv. JellemeztĂĽk az AG termolumineszcencia sávot, Ă©s bemutattuk alkalmazását gazdasági növĂ©nyek stressztűrĹ‘ kĂ©pessĂ©gĂ©nek vizsgálatában. | The research aimed to obtain a better insight into the regulatory processes involved in the development of stress tolerance in cereals, with special regard to antioxidant systems that regulate the quantity of reactive oxygen species (ROS). The contribution of antioxidant enzyme systems to defence against abiotic stress factors was investigated in several crops, particularly maize and wheat. Different cereal species were found to have elaborated diverse strategies for the regulation of ROS quantities. Light was proved to play a role in the achievement of maximum frost resistance in wheat. In this connection, changes occurring in the cyclic electron transport chain, in various antioxidants, in the salicylic acid metabolism and in membrane lipids during low temperature hardening were investigated under varying light conditions. It was found that when studying the role of salicylic acid-dependent signal transduction pathways it is important to consider not only salicylic acid itself, but also changes in its precursors. In addition it was demonstrated that in intact leaves a single turnover flash resulted in a complex thermoluminescence band, the high temperature (~ 40°C) component of which is an AG band. The latter was analysed, and its application in determining the stress tolerance of crops was discussed
Az abiotikus és a biotikus stressz és stresszellenállóság kapcsolata növényekben = Abiotic and biotic stress interactions and the cross-tolerance phenomena in plants
EredmĂ©nyeinkbĹ‘l egyrĂ©szt jĂłl látszik az, hogy a növĂ©nyt Ă©rt abiotikus stressz kĂ©pes toleranciát elĹ‘idĂ©zni egy következĹ‘ abiotikus stressz, vagy oxidatĂv stresszt okozĂł kĂ©miai kezelĂ©s kedvezĹ‘tlen hatásaival szemben (dohány alacsonyhĹ‘mĂ©rsĂ©kleti stressz, gabonafĂ©lĂ©k paraquat Ă©s hidrogĂ©n-peroxid kezelĂ©ses). Ez a fajta vĂ©delem azonban növĂ©nyi kĂłrokozĂłk fertĹ‘zĂ©sĂ©vel szemben nem, vagy csak nagyon korlátozott mĂ©rtĂ©kben hatásos, valĂłszĂnűleg ha a kĂłrokozĂł iránt a növĂ©ny fogĂ©kony (enyhe ozmotikus stressz csökkentette fogĂ©kony Bezosztaja-1 bĂşzafajta Ă©rzĂ©kenysĂ©gĂ©t a Drechslera tritici-repentis gomba fertĹ‘zĂ©sĂ©vel szemben). Rezisztens kapcsolatok esetĂ©ben viszont az elĹ‘zetesen alkalmazott abiotikus stressz csökkentette a növĂ©ny ellenállĂłságát (ozmotikus stressz hatása rezisztens M-3 bĂşzagenotĂpus Dreschlera tritici-repentis, alacsony hĹ‘mĂ©rsĂ©klet hatása rezisztens Marshall bĂşzafajta levĂ©lrozsda Ă©s alacsony hĹ‘mĂ©rsĂ©klet hatása inkompatibilis Xanthi-nc dohány TMV ellenállĂłságára). Arabidopsis thaliana-ban a NADPH-oxidázokat kĂłdolĂł rboh gĂ©nek, illetve az AtNOS1 (AtNOA1) gĂ©n közvetlenĂĽl vagy közvetve rĂ©szt vesznek a ROF, Ă©s az NO kĂ©pzĹ‘dĂ©sĂ©ben. Mi olyan Arabidopsis mutánsokkal, Ă©s kettĹ‘s mutánsokkal dolgoztunk, amikben az emlĂtett gĂ©nek nem fejezĹ‘dnek ki. Kimutattuk, hogy az AtNOS1 mutáns növĂ©nyek fejlĹ‘dĂ©sĂ©t jobban lelassĂtja tartĂłs hidegkezelĂ©s (5 °C), mint a vad tĂpusĂş növĂ©nyekĂ©t, illetve ha idĹ‘sebb korban helyezzĂĽk Ĺ‘ket alacsony hĹ‘mĂ©rsĂ©kletre, akkor kevesebb antocián vegyĂĽletet halmoznak fel. | Our results strongly support the view, that an abiotic stress can induce tolerance in plants against the harmful effect of an other abiotic or chemically induced oxidative stress (low temperature stress of tobacco, paraquat or H2O2 treatment of cereals). This type of defense is not or only partly effective against plant pathogens, probably when the plant is susceptible to the pathogen (slight osmotic stress decreased sensitivity of the susceptible Bezosztaja-1 wheat to infection by Drechslera tritici-repentis). However, in the case of resistant interactions, the previously applied abiotic stress decreased resistance of plant (effect of osmotic stress on the resistant M-3 wheat genotype to Drechslera tritici-repentis, effect of low temperature on resistance of wheat Marshall to leaf rust and on resistance of incompatible Xanthi-nc tobacco to TMV). In Arabidopsis thaliana rboh genes encoding NADPH-oxidase, or the gene AtNOS1 (AtNOA1) directly or indirectly participate in production of ROS and NO. By using single or double mutants of A. thaliana not expressing the above genes we could demonstrate that development of AtNOS1 mutant plants was slowed down more by long-term cold treatment (5 °C) than of wild type plants, and at older age at low temperature they accumulate less anthocyanins
Természetes vegyület, az S-metilmetionin hatásának vizsgálata a paradicsom és a kukorica fiziológiai sajátságaira, biotikus és abiotikus stressztoleranciájára = Effect of the natural compound S-methylmethionine on the physiological characteristics, biotic and abiotic stress tolerance of tomato and maize
Az S-metilmetionin (SMM) stresszvĂ©delemben betöltött szerepĂ©t vizsgáltuk. MegállapĂtottuk, hogy ez a termĂ©szetes, nem proteinogĂ©n aminosav jelentĹ‘s szerepet játszik a vizsgált növĂ©nyek abiotikus Ă©s biotikus stresszorokkal szembeni vĂ©dekezĹ‘kĂ©pessĂ©gĂ©nek kialakĂtásában, a stressztolerancia növelĂ©sĂ©ben. KözvetlenĂĽl szerepel a kĂ©nanyagcsere alapvetĹ‘ folyamataiban, befolyásolja poliaminok bioszintĂ©zisĂ©t, mint az S-adenozilmetionin prekurzora Ă©s mint aminopropil-donor vegyĂĽlet membránvĂ©dĹ‘, stabilizálĂł hatásĂş. TranszkripciĂł szinten elĹ‘segĂti a hidegstressz elleni vĂ©delemben központi szabályozĂłkĂ©nt működĹ‘, számos gĂ©n kifejezĹ‘dĂ©sĂ©t egyĂĽtt szabályozĂł CBF transzkripciĂłs faktorok expressziĂłját. Növeli az ugyancsak sokoldalĂş szabályozĂł Ă©s stresszvĂ©dĹ‘ poliaminok, valamint az általános stresszvĂ©delemben jelentĹ‘s fenilpropanoidok (fenoloidok, antociánok) szintĂ©zisĂ©Ă©rt felelĹ‘s gĂ©nek expressziĂłját. Mindezek következmĂ©nyekĂ©nt a metabolomikai szinten bekövetkezĹ‘ változások jelentĹ‘s fiziolĂłgiai választ eredmĂ©nyeznek. Fontos szerepe van egy- Ă©s kĂ©tszikű növĂ©nyek vĂrusok elleni vĂ©delmĂ©ben is, csökkentve a vĂruskoncentráciĂłt, lassĂtva a vĂrusok terjedĂ©sĂ©t Ă©s szaporodását a gazdanövĂ©nyekben, amihez hozzájárulhat, hogy fokozza a hormonok Ă©s a stresszvĂ©dĹ‘ kĂ©nvegyĂĽletek kĂ©pzĂ©sĂ©ben fontos szerepet betöltĹ‘ S-adenozilmetionin szintĂ©zisĂ©Ă©rt felelĹ‘s gĂ©n expressziĂłját. Az SMM hatására jellemzĹ‘ a priming hatás, ami elĹ‘kĂ©szĂti a növĂ©nyt a stresszre Ă©s lehetĹ‘vĂ© teszi a gyorsabb Ă©s hatĂ©konyabb stresszválaszt. | The present work aimed to reveal the multiple role of SMM in protection against biotic and abiotic stressors. We proved that this non–proteinogenic amino acid has an important function in the development of defence potential and in the improvement of stress and disease tolerance of examined plants. At the level of transcription SMM exerts its effect via central regulatory factor CBF, which influences the expression of number of genes during cold stress as a coordinator. The effect of SMM is chiefly manifested in its influence on the expression of CBFs that act as central coordinator in the regulation of number of genes during cold stress. In addition, SMM enhances the expression of regulatory and stress protecting polyamines and the expression of genes coding for proteins with beneficial influence in defence compound phenolics, for instance anthocyanins. The changes of gene expression result in changes of metabolomic and physiological processes of plants. SMM has an important role in biotic stress protection against both of TSWV virus of tomato and the MDMV virus of maize, decreasing the virus concentrations and moderating their replication in plant. This beneficial influence may be due to its effect in increasing the expression of gene responsible for S-adenosylmethionine synthesis, which is important in the synthesis of stress protecting compounds. We found that SMM characteristically affects due to a priming effect, resulting in faster and improved stress response
Abiotikus stressztényezők hatása a kukorica (Zea mays L.) anyagcseréjére és egyedfejlődésére = Effect of abiotic stress factors on maize (Zea mays L.) metabolism and plant development
Kutatásunk során a kĂ©nanyagcsere egyik meghatározĂł intermedierjĂ©nek, az S-metil-metioninnak (SMM) alacsony hĹ‘mĂ©rsĂ©kleti stresszt csökkentĹ‘ hatását tanulmányoztuk elsĹ‘sorban kukoricában. BizonyĂtottuk az SMM-indukált poliaminszintĂ©zis tĂ©nyĂ©t nemcsak kukoricában, hanem más gazdasági növĂ©nyekben is. MegállapĂtottuk, hogy a hidegre Ă©rzĂ©keny beltenyĂ©sztett kukoricavonalakban nagyobb mennyisĂ©gben szintetetizálĂłdik SMM hatására spermidin, mint a toleráns genotĂpusokban. Az SMM-indukált spermidin nemcsak a kukoricában, hanem más gazdasági növĂ©nyekben (Ĺ‘szi bĂşza, borsĂł, szĂłja) is csökkenti a membránok károsodását, Ă©s ezen keresztĂĽl az ionkiáramlás mĂ©rtĂ©kĂ©t. Igazoltuk az SMM fotoszintĂ©zisre gyakorolt pozitĂv hatását is, mert megnöveli a PSII hatĂ©konyságát jellemzĹ‘ Fv/Fm hányadost, Ă©s megemeli az össz-klorofill mennyisĂ©gĂ©t a kukorica genotĂpusok leveleiben szuboptimális (6-10°C) hĹ‘mĂ©rsĂ©kleteken. BizonyĂtottuk, hogy alacsony hĹ‘mĂ©rsĂ©kleti stressz során az SMM egyes antioxidáns enzimek aktivitását serkenti, Ăgy csökkentve közvetve a reaktĂv oxigĂ©nformák káros hatását. RĂ©szletesen tanulmányoztuk a poliaminszintĂ©zis kulcsenzimeinek (ADC, ODC, SAMDC) gĂ©nexpressziĂłját 24 Ăłrás SMM, illetve SMM+hidegkezelĂ©s hatására. MegállapĂtottuk, hogy a legnagyobb változás az ADC expressziĂłjában volt kimutathatĂł. Igazoltuk, hogy mind a hideg, mind az SMM hatására már az elsĹ‘ ĂłrátĂłl kezdve gyorsan emelkedett a CBF faktor expressziĂłja is. | Investigations were made on the ability of S-methyl-methionine (SMM), an important intermediary compound in the sulphur metabolism, to reduce low temperature stress, especially in maize. The existence of SMM-induced polyamine synthesis was confirmed not only in maize, but also in other crops. It was found that larger quantities of spermidine were synthesised in response to SMM treatment in chilling-sensitive inbred maize lines than in tolerant genotypes. The SMM-induced spermidine reduced membrane damage, and consequently the extent of electrolyte leakage, not only in maize, but also in other crops (winter wheat, pea, soybeans). SMM was also demonstrated to have a positive effect on photosynthesis, since it increased the Fv/Fm quotient indicative of the efficiency of PSII and induced a rise in the total chlorophyll content in the leaves of maize genotypes at suboptimal (6?10°C) temperatures. In the course of low temperature stress SMM was shown to stimulate the activity of certain antioxidant enzymes, thus indirectly reducing the damaging effect of reactive oxygen species. Detailed studies were made on the gene expression of key enzymes in polyamine synthesis (ADC, ODC, SAMDC) as the result of 24-h treatment with SMM or SMM + chilling. The greatest change was detected in the ADC expression. Both chilling and SMM led to a rapid increase in the expression of the CBF factor within an hour of treatment.
szalai.indd
ABSTRACT Two-week-old maize plants were treated with 50 or 100 mM NaCl for seven days. Leaves and roots were collected for measurements on salicylic acid and antioxidant enzyme activity on the 1 st , 3 rd and 7 th days of treatment and after four days of recovery. The quantum yield of photosystem II decreased after 7 days in maize plants treated with 100 mM NaCl. There were no changes in the catalase and ascorbate peroxidase activity. The glutathione-S-transferase, glutathione reductase and guaiacol peroxidase activities increased. There were no changes in the level of endogenous free and bound salicylic acid. The free o-hydroxy-cinnamic acid (oHCA) content increased after 7 days in the leaves, while the bound oHCA level increased after 4 days of recovery. It has been concluded that oHCA may play an important role in stress processes
Antioxidant activity and chilling tolerance of young maize inbred lines and their hybrids
Six maize hybrids and their parental inbred lines, grown under controlled conditions, were tested for chilling tolerance using the chlorophyll fluorescence induction technique. The genotypes were ranked based on the decrease in the F
v
/F
m
parameter after chilling stress at 5°C. The activities of enzymes playing a role in stress defence mechanisms (catalase, glutathione reductase, ascorbate peroxidase, guaiacol peroxidase and glutathione-S-transferase) were determined in control plants and after 1 day of cold treatment. The results suggest that although there are differences between the genotypes in the activities of almost all the antioxidant enzymes, these differences do not reflect the differences in the chilling tolerance