UV-B radiation modifies the acclimation processes to drought or cadmium in wheat

Under natural conditions plants are often subjected to multiple stress factors. The main aim of the present work was to reveal how UV-B radiation affects acclimation to other abiotic stressors. Wheat seedlings grown under normal light conditions or normal light supplemented with UV-B radiation were exposed to drought or Cd stress and were screened for changes in the contents of salicylic acid and its putative precursor ortho-hydroxy-cinnamic acid, and in the activity of the key synthesis enzyme, phenylalanine ammonia lyase. Certain other protective mechanisms, such as antioxidant enzyme activities and polyamines, were also investigated. PEG treatment under UV-B radiation did not cause wilting, but resulted in more pronounced salicylic acid accumulation, which may provide protection against drought stress in wheat plants. In contrast, the high level of salicylic acid accumulation in Cd-treated plants was not further enhanced by UV-B stress, but resulted in pronounced oxidative stress and the activation of antioxidant systems and polyamine synthesis. Changes in the levels of phenolic compounds are accompanied by increased phenylalanine ammonia lyase activity in the roots, but not in the leaves. The similar pattern observed for stress-induced changes in salicylic acid and ortho-hydroxy-cinnamic acid contents suggested that salicylic acid may play a decisive role via ortho-hydroxy-cinnamic acid. The results indicated that UV-B radiation might have either a positive or negative impact under the same conditions in wheat, depending on the type of secondary abiotic stress factor. The protective or damaging effects observed may be related to changes in the levels of phenolic compounds

Modulation of gene expression in roots of lupine (Lupinus luteus) and soybean (Glycine max) seedlings exposed to cadmium and lead

Wydział Biologii: Instytut Biologii EksperymentalnejToksyczne czynniki środowiska, w tym metale ciężkie, wywołują w organizmach eukariotycznych szereg zmian morfologicznych, fizjologicznych i biochemicznych. Celem pracy było poznanie regulacji genów indukowanych w obecności metali ciężkich w korzeniach siewek dwóch gatunków roślin motylkowatychych: soi (Glycine max cv. Nawiko) i łubinu (Lupinus luteus cv. Juno) traktowanych przez 48 godzin jonami kadmu (0-25 mg/l) i ołowiu (0-350 mg/l). Badania obejmowały identyfikację białek metodą spektrometrii mas, analizę poziomu kodujących te białka mRNA metodą RT-PCR, analizę aktywności odpowiednich białek enzymatycznych lub pomiary zawartości odpowiednich metabolitów wtórnych. Badania pozwoliły na identyfikację licznych białek biorących udział w reakcji roślin na stres metali ciężkich, w tym: histonów H2B, H2AX, H4, syntazy sacharozowej, syntazy metioniny, syntazy chalkonowej, dehydrogenazy aldehydu-3-fosfoglicerynowego, białek HSP oraz helikazy. Uzyskane wyniki sugerują, że w odpowiedzi roślin na działanie jonów metali ciężkich biorą udział białka należące do różnych szlaków metabolicznych. Niektóre z tych procesów należy zaliczyć do uniwersalnej odpowiedzią roślin na stres, natomiast inne są specyficzne dla danego metalu. Ekspresja genów indukowana metalami cieżkimi podlega kontroli na poziomie transkrypcji jak i potranskrypcyjnie. Reakcja roślin na czynnik stresowy zależy od rodzaju metalu, dawki oraz gatunku rośliny. Uzyskane wyniki wskazują, że rośliną mogą przetrwać w środowisku zanieczyszczonym metalami ciężkimi dzięki skoordynowanej sieci procesów molekularnych, które są często specyficzne dla określonego gatunku .Heavy metals, such as cadmium and lead, have become a serious environmental problem leading to toxic effects in plants and dangerous health effects. The aim of this thesis was the identification of metal-induced proteins in two plant species: soybean (Glycine max cv. Nawiko) and yellow lupine (Lupinus luteus v. Juno) as well as the analysis of respective genes expression on the different level of their regulation. The stress responses to heavy metals were analyzed in plants treated for 48h with Pb2+ (0−350 mg/l) and Cd2+ (0−25 mg/l) ions. This research includes: the gel electrophoresis of protein extracts induced by Cd2+ or Pb2+ followed by mass spectrometry, the analysis of genes expression coding selected proteins on the level of transcription by RT-PCR and the analysis of either enzyme activity or respective metabolites content. Several metal-induced proteins such as histone proteins (H2B, H2AX, H4), sucrose synthase, methionine synthase chalcone synthase, glyceraldehyde-3-phosphate dehydrogenase, heat shock proteins and helicase were identified. The obtained data suggest that the events evoked by the heavy metals involved several proteins from various metabolic pathways. Some of these processes constitute a general plant stress response and are not solely specific to metals actions. The expression of genes induced by metals is controlled at transcriptional or posttranscriptional level. Furthermore, the specific plant reaction to stress factors depended on the metal ion, dose and plant species. It is concluded that a coordinated network of species-specific molecular processes allow plants to survive in metal-containing environments

Modulation of gene expression in roots of lupine (Lupinus luteus) and soybean (Glycine max) seedlings exposed to cadmium and lead

Wydział Biologii: Instytut Biologii EksperymentalnejToksyczne czynniki środowiska, w tym metale ciężkie, wywołują w organizmach eukariotycznych szereg zmian morfologicznych, fizjologicznych i biochemicznych. Celem pracy było poznanie regulacji genów indukowanych w obecności metali ciężkich w korzeniach siewek dwóch gatunków roślin motylkowatychych: soi (Glycine max cv. Nawiko) i łubinu (Lupinus luteus cv. Juno) traktowanych przez 48 godzin jonami kadmu (0-25 mg/l) i ołowiu (0-350 mg/l). Badania obejmowały identyfikację białek metodą spektrometrii mas, analizę poziomu kodujących te białka mRNA metodą RT-PCR, analizę aktywności odpowiednich białek enzymatycznych lub pomiary zawartości odpowiednich metabolitów wtórnych. Badania pozwoliły na identyfikację licznych białek biorących udział w reakcji roślin na stres metali ciężkich, w tym: histonów H2B, H2AX, H4, syntazy sacharozowej, syntazy metioniny, syntazy chalkonowej, dehydrogenazy aldehydu-3-fosfoglicerynowego, białek HSP oraz helikazy. Uzyskane wyniki sugerują, że w odpowiedzi roślin na działanie jonów metali ciężkich biorą udział białka należące do różnych szlaków metabolicznych. Niektóre z tych procesów należy zaliczyć do uniwersalnej odpowiedzią roślin na stres, natomiast inne są specyficzne dla danego metalu. Ekspresja genów indukowana metalami cieżkimi podlega kontroli na poziomie transkrypcji jak i potranskrypcyjnie. Reakcja roślin na czynnik stresowy zależy od rodzaju metalu, dawki oraz gatunku rośliny. Uzyskane wyniki wskazują, że rośliną mogą przetrwać w środowisku zanieczyszczonym metalami ciężkimi dzięki skoordynowanej sieci procesów molekularnych, które są często specyficzne dla określonego gatunku .Heavy metals, such as cadmium and lead, have become a serious environmental problem leading to toxic effects in plants and dangerous health effects. The aim of this thesis was the identification of metal-induced proteins in two plant species: soybean (Glycine max cv. Nawiko) and yellow lupine (Lupinus luteus v. Juno) as well as the analysis of respective genes expression on the different level of their regulation. The stress responses to heavy metals were analyzed in plants treated for 48h with Pb2+ (0−350 mg/l) and Cd2+ (0−25 mg/l) ions. This research includes: the gel electrophoresis of protein extracts induced by Cd2+ or Pb2+ followed by mass spectrometry, the analysis of genes expression coding selected proteins on the level of transcription by RT-PCR and the analysis of either enzyme activity or respective metabolites content. Several metal-induced proteins such as histone proteins (H2B, H2AX, H4), sucrose synthase, methionine synthase chalcone synthase, glyceraldehyde-3-phosphate dehydrogenase, heat shock proteins and helicase were identified. The obtained data suggest that the events evoked by the heavy metals involved several proteins from various metabolic pathways. Some of these processes constitute a general plant stress response and are not solely specific to metals actions. The expression of genes induced by metals is controlled at transcriptional or posttranscriptional level. Furthermore, the specific plant reaction to stress factors depended on the metal ion, dose and plant species. It is concluded that a coordinated network of species-specific molecular processes allow plants to survive in metal-containing environments

Activation of phenylpropanoid pathway in legume plants exposed to heavy metals. Part II. Profiling of isoflavonoids and their glycoconjugates induced in roots of lupine (lupinus luteus) seedlings treated with cadmium and lead

We examined changes in profiles of isoflavonoids in roots of lupine (Lupinus luteus L. cv. Juno) seedlings in response to treatment with two heavy metals: cadmium (at 10 mg/l) and lead (at 150 mg/l). Overall, 21 flavonoid conjugates were identified in root extracts, some of them with up to six positional isomers. The total amount of all isoflavonoids increased by about 15 % in cadmium-treated plants and by 46 % in lead-treated ones. Heavy metals markedly increased the content of two compounds: 2'-hydroxygenistein glucoside and 2'-hydroxygenistein 7-O-glucoside malonylated. Possible functions of the identified isoflavonoids in yellow lupine exposed to heavy metal stress are discussed

Light regulation of cadmium-induced cell death in Arabidopsis

Cadmium is an environmental pollutant with deleterious effects on both prokaryotic and eukaryotic organisms. In plants, the effects of cadmium toxicity are concentration dependent; lower doses destabilize many physiological processes and inhibit cell growth and multiplication, while higher doses evoke a more severe response that triggers activation of cell death. We recently investigated the effects of light on cadmium toxicity in Arabidopsis using a cell suspension culture system. Although not affecting the inhibitory effects on cell multiplication, we found that light is a powerful regulator of Cd-induced cell death. A very specific proteomic response, which was clearly controlled by light, preceded cell death. Here we discuss the implications of these findings and highlight similarities between the regulation of cell death triggered by Cd and fumonisin B1. We consider how both compounds could be useful tools in dissecting plant cell death signaling

Activation of phenylpropanoid pathway in legume plants exposed to heavy metals. Part I. Effects of cadmium and lead on phenylalanine ammonia-lyase gene expression, enzyme activity and lignin content

Species-specific changes in expression of phenylalanine ammonia-lyase (PAL) and lignin content were detected in roots of soybean (Glycine max L.) and lupine (Lupinus luteus L.) seedlings treated with different concentrations of cadmium (Cd2+, 0-25 mg/l) or lead (Pb2+, 0-350 mg/l). The stimulatory effect of both metals was observed in mRNA coding for PAL in soybean. In the case of lupine, changes of PAL mRNA level were dependent on the metal used: Cd2+ caused a decrease, whereas Pb2+ an increase of PAL transcript level. The activity of PAL was enhanced in both plant species at higher metal concentrations (15-25 mg/l of Cd2+ or 150-350 mg/l of Pb2+); however it was not directly correlated with PAL mRNA. This suggests a transcriptional and posttranscriptional control of PAL expression under heavy metals stress. In soybean, Cd2+ or Pb2+ treatment increased lignin content, while in lupine the effect was opposite. The decreased lignin accumulation in lupine roots in response to heavy metals, despite an increased PAL activity, suggests that the activated phenylpropanoid pathway was involved in the synthesis of secondary metabolites other than lignin