E. F. Abd_Allah

Alleviation of salt-induced adverse impact via mycorrhizal fungi in Ephedra aphylla Forssk

The current investigation was carried out to examine the role of arbuscular mycorrhizal fungi (AMF) in alleviating adverse effects of salt stress in Ephedra aphylla. The plants were exposed to 75 and 150 mM sodium chloride (NaCl) stress with and without application of AMF. Salt stress caused significant decrease in chlorophyll and carotenoid contents; however, the application of AMF restored the pigments content in salt-affected plants. Proline, phenols, and lipid peroxidation were increased with increasing concentration of NaCl, but lower accumulation has been reported in plants treated with AMF. NaCl stress also showed increase in different antioxidant enzymes activities (catalase, ascorbate peroxidase, peroxidase, glutathione reductase, and superoxide dismutase), and further increase was observed in plants treated with AMF. The nutrient uptake, Na+ and Na/K ratio increased and potassium and phosphorus were decreased with increasing concentration of NaCl in the present study. However, the colonization with AMF significantly increased K+ and P and reduced Na+ uptake. It is concluded that presown soil treatment with AMF reduced severity of salt stress in E. aphylla through alterations in physiological parameters, antioxidants and uptake of nutrients.

Alleviation of cadmium stress in Solanum lycopersicum L. by arbuscular mycorrhizal fungi via induction of acquired systemic tolerance.

Experiments were conducted to evaluate cadmium (Cd) stress-induced changes in growth, antioxidants and lipid composition of Solanum lycopersicum with and without arbuscular mycorrhizal fungi (AMF). Cadmium stress (50 μM) caused significant changes in the growth and physio-biochemical attributes studied. AMF mitigated the deleterious impact of Cd on the parameters studied. Cadmium stress increased malonaldehyde and hydrogen peroxide production but AMF reduced these parameters by mitigating oxidative stress. The activity of antioxidant enzymes enhanced under Cd treatment and AMF inoculation further enhanced their activity, thus strengthening the plant’s defense system. Proline and phenol content increased in Cd-treated as well as AMF-inoculated plants providing efficient protection against Cd stress. Cadmium treatment resulted in great alterations in the main lipid classes leading to a marked change in their composition. Cadmium stress caused a significant reduction in polyunsaturated fatty acids resulting in enhanced membrane leakage. The present study supports the use of AMF as a biological means to ameliorate Cd stress-induced changes in tomato.

Quantitative proteomics analysis reveals that S-nitrosoglutathione reductase (GSNOR) and nitric oxide signaling enhance poplar defense against chilling stress

AbstractMain conclusionNO acts as the essential signal to enhance poplar tolerance to chilling stress via antioxidant enzyme activities and protein S-nitrosylation modification, NO signal is also strictly controlled by S-nitrosoglutathione reductase and nitrate reductase to avoid the over-accumulation of reactive nitrogen species. Poplar (Populus trichocarpa) are fast growing woody plants with both ecological and economic value; however, the mechanisms by which poplar adapts to environmental stress are poorly understood. In this study, we used isobaric tags for relative and absolute quantification proteomic approach to characterize the response of poplar exposed to cold stress. We identified 114 proteins that were differentially expressed in plants exposed to cold stress. In particular, some of the proteins are involved in reactive oxygen species (ROS) and reactive nitrogen species (RNS) metabolism. Further physiological analysis showed that nitric oxide (NO) signaling activated a series of downstream defense responses. We further demonstrated that NO activated antioxidant enzyme activities and S-nitrosoglutathione reductase (GSNOR) activities, which would reduce ROS and RNS toxicity and thereby enhance poplar tolerance to cold stress. Suppressing NO accumulation or GSNOR activity aggravated cold damage to poplar leaves. Moreover, our results showed that RNS can suppress the activities of GSNOR and NO nitrate reductase (NR) by S-nitrosylation to fine-tune the NO signal and modulate ROS levels by modulating the S-nitrosylation of ascorbate peroxidase protein. Hence, our data demonstrate that NO signaling activates multiple pathways that enhance poplar tolerances to cold stress, and that NO signaling is strictly controlled through protein post-translational modification by S-nitrosylation.

Alleviation of abiotic salt stress in Ochradenus baccatus (Del.) by Trichoderma hamatum (Bonord.) Bainier

The current study was taken up to examine the role of bioagent (Trichoderma hamatum) in mitigating the deleterious effects of NaCl stress in Ochradenus baccatus. Varying concentrations of salt (0, 75, and 150 mM) were used to observe the effect on growth, pigments, some key metabolic attributes, antioxidant enzymes, and elemental accumulation in O. baccatus. The results indicated significant decrease in seed germination, plant growth, pigment content, membrane stability index, tissue water content, and total lipid content with salt stress. Lipid peroxidation increases with the increasing concentration of NaCl. Moreover, salinity stimulated the biosynthesis of phenols, diacylglycerol, sterol esters, nonesterified fatty acids, and enzymatic antioxidants like superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, glutathione reductase. The Na+ content in shoot increases with elevated levels of NaCl concentration, accompanied with significant decreases in K+, Mg2+, and Ca2+. Application of bioagent (T. hamatum) has been observed to alleviate the antagonistic effect of salt stress on plant growth and metabolic processes. In absence and presence of salt stress, the bioagent stimulated the plant growth and alter the plant metabolism through the modification of the above parameters.

Exogenous Application of Selenium Mitigates Cadmium Toxicity in Brassica juncea L. (Czern & Cross) by Up-Regulating Antioxidative System and Secondary Metabolites

The main aim of the present study was to examine the role of selenium (Se) in ameliorating the toxic effect of cadmium (Cd) in mustard (Brassica juncea) plants. The plants exposed to elevated levels of Cd exhibited reduced biomass, pigment content, and relative water content (RWC). However, supplementation of Se restores the negative effect of Cd and increases biomass, pigment content, and RWC. Osmolyte (proline and glycine betaine) and sugar content were increased under Cd stress and further increase was observed with addition of Se. Cd decreased protein content and supplementation of Se increases it to appreciable levels. Cd also increased production of H2O2 and lipid peroxidation, electrolyte leakage, and the activities of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, and glutathione reductase. Supplementation of Se decreased accumulation of H2O2 and lipid peroxidation, increased the activities of antioxidant enzymes to greater levels, and regulates Cd accumulation in roots and shoots. Ascorbic acid (AsA) and flavonoids decreased with elevated concentrations of Cd; however, tocopherol and total phenols were increased with the same concentrations of Cd. Se application maintains AsA and flavonoid content, and further increase in tocopherol and total phenols were observed with Se in the present study. Overall the results confirm that exogenous application of Se mitigates the negative effects of Cd stress in mustard plants through the regulation of osmoprotectants, antioxidant enzymes, and secondary metabolites.

Effect of salinity on moisture content, pigment system, and lipid composition in Ephedra alata Decne

The present work was carried out to uncover the effect of salinity stress on shoot moisture percentage, pigment content and lipid composition of Ephedra alata Decne. The results suggested that salinity caused significant decrease in plant moisture content. The chl. a, b and carotenoids showed significant decrease with increasing concentration of salt. Total pigment content also showed decline at all salt stress levels. Salt stress caused significant decrease in total lipids (TL), triacylglycerol (TG) and sterol (S) accompanied with an increase in diacylglycerol (DG), sterol ester (SE), and non-esterified fatty acids (FAA) of E. alata. Moreover, saline stress caused significant decrease in all phospholipid fractions except phosphatidic acid which increases during salt stress. Salinity stress resulted in increase of saturated fatty acids and decreases the percentage of un-saturated fatty acids in E. alalta.

Bioremediation of adverse impact of cadmium toxicity on Cassia italica Mill by arbuscular mycorrhizal fungi.

Cassia italica Mill is an important medicinal plant within the family Fabaceae. Pot experiment was conducted to evaluate cadmium stress induced changes in physiological and biochemical attributes in C. italica with and without arbuscular mycorrhizal fungi (AMF). Cadmium stressed plant showed reduced chlorophyll pigment and protein content while AMF inoculation enhanced the chlorophyll and protein content considerably. AMF also ameliorated the cadmium stress induced reduction in total chlorophyll and protein contents by 19.30% and 38.29%, respectively. Cadmium stress enhanced lipid peroxidation while AMF inoculation reduced lipid peroxidation considerably. Increase in proline and phenol content was observed due to cadmium stress and AMF inoculation caused a further increase in proline and phenol content ensuring better growth under stressed conditions. AMF alone also enhanced proline and phenol content. Activity of antioxidant enzymes enhanced under cadmium treatment and AMF inoculation further enhanced their activity thereby strengthening the antioxidant system. Enhanced activities of antioxidants and increased accumulation of osmolytes help plants to avoid damaging impact of oxidative damage. The research has shown that AMF inoculation mitigated the negative impact of stress by reducing the lipid peroxidation and enhancing the antioxidant activity. The present study strongly supports employing AMF as the biological mean for enhancing the cadmium stress tolerance of C. italica.

Ethnomedicinal Evaluation of Medicinal Plants Used against Gastrointestinal Complaints

Aim of the present study was to document ethnomedicinal plants used against gastrointestinal complaints in five selected remote regions of Pakistan and to select potential medicinal plants for further in vitro and in vivo investigation. Data on ethnomedicinal plants and ethnographic profile of respondents was documented using semistructured questionnaires. The present study revealed utilization of 52 medicinal plants for the treatment of different gastrointestinal infections in studied regions. Apiaceae was the most dominant family reported to be used for the treatment of these infections (4 plants). Among all the plant parts fruit (24%), whole plants and leaves (23% each) were the most preferred plant parts used by the healers. Dosage of recipe was found to be related with the age of the patient. Highest degree of informant consensus was reported for vomiting, nausea (0.92 each), abdominal pain (0.9), and diarrhea (0.89). Withania coagulans scored highest FL value (86%) followed by Mentha longifolia and Melia azadirachta ranked second with FL value (75% each). Young generation was found to possess little traditional knowledge about utilizing plant recipes against these infections. Plants with high Fic and FL values should be subjected for further phytochemical and pharmacological investigation for scientific validation.

The role of nitric oxide signalling in response to salt stress in Chlamydomonas reinhardtii.

AbstractMain conclusionNitric oxide signal and GSNOR activity play an essential role forChlamydomonas reinhardtiiresponse to salt stress. The unicellular alga Chlamydomonas reinhardtii is one of the most important model organisms phylogenetically situated between higher plants and animals. In the present study, we used comparative proteomics and physiological approaches to study the mechanisms underlying the response to salt stress in C. reinhardtii. We identified 74 proteins that accumulated differentially after salt stress, including oxidative enzymes and enzymes associated with nitric oxide (NO) metabolism, cell damage, and cell autophagy processes. A set of antioxidant enzymes, as well as S-nitrosoglutathione reductase (GSNOR) activity, were induced to balance the cellular redox status during short-term salt stress. Enzymes involved in DNA repair and cell autophagy also contribute to adaptation to short-term salt stress. However, under long-term salt stress, antioxidant enzymes and GSNOR were gradually inactivated through protein S-nitrosylation, leading to oxidative damage and a reduction in cell viability. Modulating the protein S-nitrosylation levels by suppressing GSNOR activity or adding thioredoxin affected the plant’s adaptation to salt stress, through altering the redox status and DNA damage and autophagy levels. Based on these data, we propose that unicellular algae use multiple strategies to adapt to salt stress, and that, during this process, GSNOR activity and protein S-nitrosylation levels play important roles.

Induction of Osmoregulation and Modulation of Salt Stress in Acacia gerrardii Benth. by Arbuscular Mycorrhizal Fungi and Bacillus subtilis (BERA 71)

The role of soil microbiota in plant stress management, though speculated a lot, is still far from being completely understood. We conducted a greenhouse experiment to examine synergistic impact of plant growth promoting rhizobacterium, Bacillus subtilis (BERA 71), and arbuscular mycorrhizal fungi (AMF) (Claroideoglomus etunicatum; Rhizophagus intraradices; and Funneliformis mosseae) to induce acquired systemic resistance in Talh tree (Acacia gerrardii Benth.) against adverse impact of salt stress. Compared to the control, the BERA 71 treatment significantly enhanced root colonization intensity by AMF, in both presence and absence of salt. We also found positive synergistic interaction between B. subtilis and AMF vis-a-vis improvement in the nutritional value in terms of increase in total lipids, phenols, and fiber content. The AMF and BERA 71 inoculated plants showed increased content of osmoprotectants such as glycine, betaine, and proline, though lipid peroxidation was reduced probably as a mechanism of salt tolerance. Furthermore, the application of bioinoculants to Talh tree turned out to be potentially beneficial in ameliorating the deleterious impact of salinity on plant metabolism, probably by modulating the osmoregulatory system (glycine betaine, proline, and phenols) and antioxidant enzymes system (SOD, CAT, POD, GR, APX, DHAR, MDAHR, and GSNOR).