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Wilt of chickpea caused by Fusarium oxysporum f. sp ciceri (FOC) is one of the most important soil borne pathogen of chickpea worldwide. Twelve indigenous isolate of Trichoderma asperellum were identified and characterized on the basis of their cultural, morphological and molecular (ITS4/6) from pulses rhizosphere of Bundelkhand region. They were evaluated against Foc for their antagonistic and growth promotion potential. Among which, two isolates (IIPRTas-1 and IIPRTas-2) were identified most promising and showed highest inhibition of mycelial growth of test pathogen (76.58 and 73.29% respectively). The isolate IIPRTas-1 was identified as multi-trait isolate for its growth promotion along with antagonistic activity. The identified multi-trait indigenous T. asperellum isolates (IIPRTas-1) from pulses rhizosphere of Bundelkhand region would be effectively utilized to minimize the crop losses through wilt disease and get incremental yield through plant growth promotion in chickpea.

Trichoderma spp. are widely used as beneficial fungi for disease management, plant growth promotion, induced resistance, and abiotic stress management. Henceforth, plays a pivotal role in sustainable agriculture around the world. The study aimed to identify a promising biocontrol agent with multi-trait properties wherein isolates of Trichoderma spp. were identified on the basis of their morphological and molecular characteristics for species-level determination. Twelve Trichoderma isolates tested in-vitro against Fusarium solani and their biochemical responses concerning defense enzymes, growth enzymes, and lytic enzymes were also assessed, further validated under pot culture conditions. Under thein-vitro study, the highest percent inhibition, specific activity of defense enzymes (PO, PPO, and SOD) and lytic enzymes (cellulase, Xylanase, CMCase, and Chitinase) production were recorded with T. asperellum (TGD-I and TSH-I) and T. harzianum (MTB-I). These three isolates exhibited growth hormones ranging from 0.01 to 0.42 μl/ml (IAA) and 0.2–0.5 μl/ml (GA3) and also showed the highest root and shoot growth promotion. This study proves that T. asperellum and T. harzianum initially isolated from hot humid tropical climate may be used as bio inoculants in subtropical areas of India for biotic stress management and plant growth promotion in vegetable crops.

This study was carried out to identify and characterize Trichoderma species isolated from rhizospheric soil of Uttar Pradesh, India, by using single spore technique. Morphological, cultural and molecular characterization were done with sequence analysis of the internal transcribed spacer (ITS) region. The classes were compared with morphological identification and rDNA sequence data for every class of all Trichoderma strains were of the same identity. These strains belonged to T. harzianum (Th azad), T. viride (01PP), T. asperellum (Tasp/CSAU), T. Koningii [TK (CSAU)], T. atroviride (71L), T. longibrachiatum (21PP), T. virens [Tvi (CSAU)], T. reesei [Tr (CSAU)], T. aggressivum [T.agg(CSAU)], T. aureoviride [T. avi (CSAU)], T. citrinoviride [T. cvi (CSAU)], T. erinaceum [T. eri (CSAU)], T. koningiopsis [T. kop (CSAU)], T. tomentosum [T. tos (CSAU)], T. mintisporum [T. mip (CSAU)], T. pubscenes [T. sce (CSAU)], T. saturnisporum [T. ssp (CSAU)], T. spirale [T. sp. (CSAU)]. Morphological studies were based on the colony appearance, growth rate and microscopic features such as branching patterns of conidiophores, the arrangement of phialospores and their shape, size and color. The 5.8S-ITS regions of the Trichoderma strains were amplified using ITS1 and ITS4 primers. The rRNA based analysis is a central method used not only to explore microbial diversity but also to identify new strains. Validations of ITS marker with 18 Trichoderma sp. were done and their sequences were deposited at NCBI GenBank their permanent accession no. were allotted.

The role of Trichoderma harzianum, Bacillus subtilis and Pseudomonas fluorescens (alone and in combination) in inducing systemic resistance in chickpea exposed to Fusarium oxysporum ciceris was investigated. Chickpea seed (var. Radhey) treatment with Trichoderma harzianum, Bacillus subtilis and Pseudomonas fluorescens alone and in combination on the germination, wilt incidence, plant growth promotion, yield, production of chlorophyll, protein, peroxidase, polyphenol oxidase and total phenol content was recorded. The results of in vitro studies revealed better performances of treatment T6 (Seed treatment with 1% Trichoderma harzianum + 2% Pseudomonas fluorescens + 2% Bacillus subtilis in combination). This treatment significantly reduced wilt incidence and increased germination, root length, shoot length, and yield as compared to untreated control. Treatment T6 also induced 1.4 per cent increase in peroxidase, 1.6 in polyphenol oxidase and 2.3 in total phenol in chickpea during pathogenesis by F. oxysporum ciceris f. sp. Similarly, 1.9% increase in chlorophyll and protein was recorded with the treatment T6 as compared to control. Present investigations will be helpful in formulating novel bioformulations using fungal and bacterial bioagents to control wilt in chickpea.

PurposeTo overcome the need of seasonal fruit ber, consumers prefer to use fruits in such a form that can be prepared easily or consumed instantly. By transforming them into powders, they can be effortlessly attained as well as preserved, stored and processed.Design/methodology/approachTo optimize the spray drying conditions for development of ber fruit powder, response surface methodology was used. The experimental design consisted of 13 runs. The levels of independent variables, i.e. inlet air temperature, varied from 153.79ºC to 196.21ºC and maltodextrin concentration, from 4.17 to 9.83 per cent. The responses were moisture content, bulk density, solubility, vitamin C, ΔE and L value.FindingsThe second-order polynomial model fitted for moisture content, bulk density, solubility, vitamin C, ΔE and L value was highly significant (p< 0.001) for each response. The inlet air temperature showed maximum influence on moisture content, bulk density, solubility and vitamin C, whereas the maltodextrin concentration showed maximum influence on bulk density, solubility, ΔE and L value. The predicted values were attained as moisture 4.90 per cent, bulk density 0.35g/ml, solubility 89.11 per cent, vitamin C 91.06mg/100g, ΔE 31.03 and L 87.78. The recommended optimum spray drying conditions were inlet air temperature and maltodextrin concentration of 166.64°C and 9.26 per cent, respectively.Originality/valueSpray drying of the underused Indian fruit ber has enhanced its utility. Ber powder can further be used as an instant beverage, in sweets, as a flavoring agent and in soft drinks.

Mitochondria are the power houses of eukaryotic cells. These organelles contain various oxidoreductase complexes. Electron transfer from different reducing equivalents channeled via these complexes drives proton translocation across the inner mitochondrial membrane, leading to ATP generation. Plant mitochondria contain alternative NAD(P)H dehydrogenases, alternative oxidase, and uncoupling protein, and TCA cycle enzymes are located in their matrix. Apart from ATP production, mitochondria are also involved in synthesis of vitamins and cofactors and participate in fatty acid, nucleotide, photorespiratory, and antioxidant metabolism. Recent emerging evidence suggests that mitochondria play a role in redox signaling and generation of reactive oxygen and nitrogen species. For mitochondrial studies, it is essential to isolate physiologically active mitochondria with good structural integrity. In this article, we explain a detailed procedure for isolation of mitochondria from various heterotrophic tissues, such as germinating chickpea seeds, potato tubers, and cauliflower florets. This procedure requires discontinuous Percoll gradient centrifugation and can give a good yield of mitochondria, in the range of 4 to 8 mg per 50 g tissue with active respiratory capacity. After MitoTracker staining, isolated mitochondria can be visualized by using a confocal microscope. The structure of mitochondria can be monitored by scanning electron microscopy. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Isolation of mitochondria from germinating chickpea seeds, potato tubers, and cauliflower florets Basic Protocol 2: Quantification of mitochondrial protein concentration by Bradford assay Basic Protocol 3: Quantification of mitochondrial respiration using single-channel free-radical analyzer Basic Protocol 4: Staining of mitochondria and confocal imaging Basic Protocol 5: Visualization of isolated mitochondria under scanning electron microscope.

Molecular oxygen (O2) is a basic requirement of life for many organisms, including plants. As a terminal electron acceptor, during mitochondrial respiration, O2 governs both the energy status and numerous aspects of cellular metabolism by influencing adenosine triphosphate (ATP) synthesis. Although O2 is essential, no active mechanism has been found in plants that can provide uniform O2 within the tissues of various plant organs, including roots and tubers, as well as germinating seeds. As a result, plants cells and tissues can face low-oxygen stress (LOS)/hypoxia under certain environmental conditions. Environmental events such as flooding/water logging can create LOS or absence of O2, and a high rate of cellular metabolism can also cause the O2 deficit. The absence of O2 as a terminal electron acceptor leads to the generation of excess electrons that can leak from the inner mitochondrial membrane, resulting in the production of reactive oxygen species (ROS). With respect to physiological signaling, ROS and nitric oxide (NO) have shown to have a dual behaviour, depending upon the cellular concentrations and/or time of exposure. Both ROS and NO can act as signaling molecules, and depending on their endogenous levels they can activate various downstream signaling pathways or can cause an oxidative burst, leading to cell damage. In addition, previous studies have shown that ROS and NO, when being present at high levels, can react with each other to produce various other forms of ROS and reactive nitrogen species (RNS). The present review focuses on different aspects of LOS and how plants sense decreases in cellular O2 concentrations. The roles played by ROS and NO in relation to maintaining redox homeostasis during impairment of energy metabolism are critically discussed.

Recent research has focused on the production of biofuel from different bio-resources, especially non-edible and underutilized plants. In this study, total lipid contents and fatty acids composition were evaluated both qualitatively and quantitatively for twelve abundant halophytes to ascertain their potential as feedstock for renewable energy. Non-succulent halophytes contained the highest total lipid content (about 5–7%, except Porteresia coarctata), followed by shrubby (about 2.6%) and succulent halophytes (1–1.8%). The FA profile shows that halophytes are a rich source of alpha-linolenic, linolenic and palmitic acids. Oleic and stearic acids were also detected in some halophytes. A low content of MUFA (except P. coarctata) was detected in all the halophytes, but the maximum content of SFA was estimated in Salicornia brachiata, Suaeda fruticosa, and P. coarctata. Halophyte Sporobolus virginicus contained more than 80% PUFA, followed by Heleochloa setulosa, Sesuvium portulacastrum, Atriplex griffithii and Salvadora persica. An important qualitative indicator density was found to be at par with recommended standards, but the cetane number of S. fruticosa and S. brachiata also matched the standards. The overall fatty acid profile of the selected halophytes makes them suitable for biofuel, and their potential could be enriched by improving agronomical practices and downstream processing.

Seed germination is crucial for the plant life cycle. We investigated the role of nitric oxide (NO) in two chickpea varieties that differ in germination capacity: Kabuli, which has a low rate of germination and germinates slowly, and Desi, which shows improved germination properties. Desi produced more NO than Kabuli and had lower respiratory rates. As a result of the high respiration rates, Kabuli had higher levels of reactive oxygen species (ROS). Treatment with the NO donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP) reduced respiration in Kabuli and decreased ROS levels, resulting in accelerated germination rates. These findings suggest that NO plays a key role in the germination of Kabuli. SNAP increased the levels of transcripts encoding enzymes involved in carbohydrate metabolism and the cell cycle. Moreover, the levels of amino acids and organic acids were increased in Kabuli as a result of SNAP treatment. 1H-nuclear magnetic resonance analysis revealed that Kabuli has a higher capacity for glucose oxidation than Desi. An observed SNAP-induced increase in 13C incorporation into soluble alanine may result from enhanced oxidation of exogenous [13C]glucose via glycolysis and the pentose phosphate pathway. A homozygous hybrid that originated from a recombinant inbred line population of a cross between Desi and Kabuli germinated faster and had increased NO levels and a reduced accumulation of ROS compared with Kabuli. Taken together, these findings demonstrate the importance of NO in chickpea germination via the control of respiration and ROS accumulation., Nitric oxide improves germination capacity of Kabuli chickpea by increasing internal oxygen concentration and minimizing reactive oxygen species.

Background and Aims: Non-dividing hepatocytes in end-stage liver disease indicates permanent growth arrest similar to senescence. Identifying senescence in vivo is often challenging and mechanisms inhibiting senescence are poorly understood. In lower organisms mitochondrial unfolded protein response (UPRMT) helps in increasing longevity; however, its role in senescence and liver disease is poorly understood. Aim of this study was to identify hepatocyte senescence and the role of UPRMT in cryptogenic cirrhosis. Methods: Doxorubicin was used to induce senescence in non-neoplastic hepatocytes (PH5CH8) and hepatoma cells (HepG2 and Huh7). Senescence-associated markers and unfolded protein response was evaluated by fluorescence microscopy, immunoblotting and gene expression. Explants/biopsies from normal, fibrosis, compensated and decompensated cirrhosis without any known etiology were examined for presence of senescence and UPRMT by immunohistochemistry and gene expression. Results: Accumulation of senescent hepatocytes in cryptogenic cirrhosis was associated with reduced proliferation, increased expression of γH2AX and p21, together with loss of LaminB1. Dysfunctional mitochondria and compromised UPRMT were key features of senescent hepatocytes both in vitro and also in decompensated cirrhosis. Intriguingly, compensated cirrhotic liver mounted strong UPRMT, with high levels of mitochondrial protease, CLPP. Overexpression of CLPP inhibited senescence in vitro, by reducing mitochondrial ROS and altering oxygen consumption. Conclusions: Our results implicate a role of hepatocyte senescence in cryptogenic cirrhosis together with a crucial role of UPRMT in preventing hepatocyte senescence. A compromised UPRMT may shift the fate of cirrhotic liver toward decompensation by exaggerating hepatocyte senescence. Restoring CLPP levels at least in cell culture appears as a promising strategy in mitohormesis, thereby, preventing senescence and possibly improving hepatocyte function. Keywords: Cryptogenic Liver Cirrhosis, Mitochondrial Respiration, Mitochondrial Unfolded Protein Response, Oxidative Stress

Background: Green gram, Vigna radiata (L.) R. Wilczek is third most important pulse crop cultivated in India. The two key insect pest viz., pod borer, Helicoverpa armigera Hubner and Tobacco leaf caterpillar, Spodoptera litura Fabricius inflicts heavy yield loss in greengram. As these are polyphagous insect pest and the crop is a short duration crop, immediate management strategy such as chemical control is very much essential to check its yield loss. The current study reports the efficacy of novel insecticide i.e. Coragen® 20 SC against above cited two insect pest in greengram. Further its effect on non-target insects and its influence on growth and survival of Bacillus thuringiensis were evaluated. Methods: Field experiments were conducted to evaluate the efficacy of Coragen® 20 SC (at four doses viz., 75 ml ha-1, 100 ml ha-1, 125 ml ha-1 150 ml ha-1), chlorpyriphos 20 EC @ 2.5 l ha-1 and emamectin benzoate 5 SG @ 220 g ha-1 against H. armigera and S. litura during kharif 2018 and 2019. Based on larval load per plant, the percent reduction in larval counts was estimated based on Henderson and Tilton method. The benefit cost ratio (BCR) was worked out for each respective year based on seed yield and net returns. Result: Coragen® 20 SC at 125 ml ha-1 and 150 ml ha-1 had resulted in highest percent reduction in larval population over control. Simultaneously, the highest BCR during kharif 2018 (6.29, 4.21) and 2019 (5.95, 5.64) were recorded from above 2 treatments. Further, Coragen® 20 SC showed compatibility with 5 Bt isolates evaluated, i.e Bt growth didn’t inhibited in nutrient agar containing field dose of Coragen 20 SC.

Field experiments were carried out in pigeonpea during Kharif 2014 to Kharif 2017 for Maruca vitrata Fabricius management through farmscaping approach with 7 different border crops (5 leguminous crops; 2 non-leguminous crops) and a sole crop. The M. vitrata larval webbing per plant was lowest and per cent decrease in webbing/plant over sole crop was highest in sorghum (2.05 and 60.95) as border crop followed by pearl millet (3.29 and 37.39). The highest mean number of Coccinella septumpunctata per plant (0.77), Cheilomenes sexmaculata per plant (0.85/plant) and spiders (0.76/plant) was recorded from sorghum as border crop with pigeonpea. The highest percent increase in above said natural enemies over sole crop was also recorded from sorghum as border crop treatment (755.6, 844.4 and 660). The highest pigeonpea yield (730.72 kg/ha) and per cent yield gain (65.81%) was also recorded with sorghum treatment. Among 5 weather parameters tested, day length (1.53) and relative humidity (-0.12) were found to influence the M. vitrata population significantly and its incidence was recorded from 41st SMW to 47th SMW.

Plant-based milk substitutes or non-dairy substitutes are among the fastest growing beverage segments worldwide. There are many reasons behind such growth. Lactose intolerance is one of the main reasons. Such milk substitutes are naturally free from lactose and have lower amount of cholesterol and fat than milk from animals. These substitutes are often more easily digested than dairy products and these also favor those people who do not suffer from lactose intolerance. Other than soy, which is the main driver of this growth instead, innovative beverages are made from nuts, grains, and seeds. These substitutes are manufactured by extracting the plant material in water, separating the liquid, and formulating the final product. Homogenization and thermal treatments are necessary to improve the suspension and microbial stabilities of commercial products that can be consumed as such or be further processed into fermented dairy-type products. The nutritional content depends on the plant source and further fortification.

Pulses play a major role in meeting the projected targets relating to food and nutritional security worldwide. The complementation of cereal-based food with grain legumes keeps the vegetarian diet nutritionally balanced. However, the productivity of these crops is severely impacted by a number of biotic, mesobiotic, and abiotic stresses causing substantial economic losses globally. Among the biotic/mesobiotic constraints, diseases and insect pests remain the most crucial factors affecting all parts of the plant at different growth stages. For the management of these insect pests and diseases, chemical pesticides are extensively employed across the world. However, the global risk associated with the environmental pollution and health hazards posing toxicity to man, plants, domestic animals, and wildlife render these chemical-based interventions ecologically unacceptable. In the context, Trichoderma is one of the most effective and attractive biological control agents (BCAs) as well as an alternative to conventional fungicides. These Trichoderma-based BCAs are economically viable and environment-friendly and represent the most competent means to sustain the existing level of agricultural production system.

Metabolomics is now considered a wide-ranging, sensitive and practical approach to acquire useful information on the composition of a metabolite pool present in any organism, including plants. Investigating metabolomic regulation in plants is essential to understand their adaptation, acclimation and defense responses to environmental stresses through the production of numerous metabolites. Moreover, metabolomics can be easily applied for the phenotyping of plants; and thus, it has great potential to be used in genome editing programs to develop superior next-generation crops. This review describes the recent analytical tools and techniques available to study plants metabolome, along with their significance of sample preparation using targeted and non-targeted methods. Advanced analytical tools, like gas chromatography-mass spectrometry (GC-MS), liquid chromatography mass-spectroscopy (LC-MS), capillary electrophoresis-mass spectrometry (CE-MS), fourier transform ion cyclotron resonance-mass spectrometry (FTICR-MS) matrix-assisted laser desorption/ionization (MALDI), ion mobility spectrometry (IMS) and nuclear magnetic resonance (NMR) have speed up precise metabolic profiling in plants. Further, we provide a complete overview of bioinformatics tools and plant metabolome database that can be utilized to advance our knowledge to plant biology.

Metallothioneins are cysteine-rich proteins, which play key roles in metal detoxification, intracellular ion homeostasis maintenance, and protection against intracellular oxidative damage. This study reports the characterization of SbMT-2 cloned from Salicornia brachiata concerning physiology, molecular, and photosynthesis efficiency. Overexpression of SbMT-2 conferred enhanced tolerance to Zn stress in transgenic tobacco supported by increased photosynthesis efficiency and crop quality compared to wild-type. The growth of transgenic and WT plants was comparable in control conditions; transgenic plants showed better growth than WT plants under stress (20 mM ZnSO4 for 30 days). After 30 days of stress, transgenic plants completed their life cycle with early maturation, whereas the WT plants did not and matured very late. About 35 pods with a total weight of 3.5 g per plant were measured in transgenic compared to WT (about 19 pods with total weight 2.5 g). Further, gas exchange and fluorescence measurements established that the SbMT-2 gene improved the photosynthetic efficiency of the transgenic line compared to WT plants during stress conditions. In addition, SbMT-2 might be involved in the selective translocation of Zn2+ under long-term stress condition. Microarray analysis showed that the expression of many Zn transporters, Zn-binding proteins, and Zn-associated proteins encoding genes was up-regulated 4–6 (log2) fold. However the expression of genes encoding other metal-binding proteins, metal metabolism-associated enzymes, and metal-inducible transcription factors were down-regulated. Furthermore, transcript expression analysis elucidated that overexpression of the SbMT-2 gene may regulate the expression pattern of metal transporter encoding genes under stress conditions. Thus, SbMT-2 is an important gene, which plays a positive role by detoxifying reactive oxygen species and maintaining photosynthesis efficiency under Zn stress conditions.

The host genetic factors play important role in determining the outcome of visceral leishmaniasis (VL). Macrophage migration inhibitory factor (MIF) is an important host cytokine, which is a key regulator of innate immune system. Genetic variants in MIF gene have been found to be associated with several inflammatory and infectious diseases. Role of MIF is well documented in leishmaniasis diseases, including Indian visceral leishmaniasis, where elevated level of serum MIF has been associated with VL phenotypes. However, there was no genetic study to correlate MIF variants in VL, therefore, we aimed to study the possible association of three reported MIF gene variants −794 CATT, −173G > C and non-coding RNA gene LOC284889 in Indian VL phenotype. Methods: Study subjects comprised of 214 VL patients along with ethnically and demographically matched 220 controls from VL endemic regions of Bihar state in India. Results: We found no significant difference between cases and controls in allelic, genotypic and haplotype frequency of the markers analysed [-794 CATT repeats (χ2 = 0.86; p = 0.35; OR = 0.85; 95% CI = 0.61?1.19); −173 G > C polymorphism (χ2 = 1.11; p = 0.29; OR = 0.83; 95% CI = 0.59?1.16); and LOC284889 (χ2 = 0.78; p = 0.37; OR = 0.86; 95% CI = 0.61?1.20)]. Conclusion: Since we did not find any significant differences between case and control groups, we conclude that sequencing of complete MIF gene and extensive study on innate and adaptive immunity genes may help in identifying genetic variations that are associated with VL susceptibility/resistance among Indians. Fil: Mishra, Anshuman. Vinoba Bhave Research Institute; India. Centre For Cellular And Molecular Biology India; India Fil: Sundaravadivel, Pandarisamy. Centre For Cellular And Molecular Biology India; India Fil: Tripathi, Sunil Kumar. Centre For Cellular And Molecular Biology India; India Fil: Jha, Rajan Kumar. Centre For Cellular And Molecular Biology India; India Fil: Badrukhiya, Jaydeep. Centre For Cellular And Molecular Biology India; India Fil: Basak, Nipa. Academy Of Scientific And Innovative Research; India. Centre For Cellular And Molecular Biology India; India Fil: Anerao, Isha. Centre For Cellular And Molecular Biology India; India Fil: Sharma, A. Surja. Centre For Cellular And Molecular Biology India; India Fil: Ajayi, Ebenezer Idowu O. Centre For Cellular And Molecular Biology India; India. Osun State University; Nigeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina Fil: Mishra, Abhishek. Institute Of Basic Sciences Agra; India Fil: Pandey, Sonika. Banaras Hindu University; India Fil: Kumar, Umesh. Centre For Cellular And Molecular Biology India; India Fil: Singh, Sakshi. Centre For Cellular And Molecular Biology India; India Fil: Nizamuddin, Sheikh. Centre For Cellular And Molecular Biology India; India Fil: Tupperwar, Nitin C.. Centre For Cellular And Molecular Biology India; India Fil: Jha, Aditya Nath. Sickle Cell Institute Chhattisgarh; India. Centre For Cellular And Molecular Biology India; India Fil: Thangaraj, Kumarasamy. Centre For Cellular And Molecular Biology India; India

BACKGROUND AND AIMS: Nitrogen (N) levels vary between ecosystems, while the form of available N has a substantial impact on growth, development and perception of stress. Plants have the capacity to assimilate N in the form of either nitrate (NO(3)(–)) or ammonium (NH(4)(+)). Recent studies revealed that NO(3)(–) nutrition increases nitric oxide (NO) levels under hypoxia. When oxygen availability changes, plants need to generate energy to protect themselves against hypoxia-induced damage. As the effects of NO(3)(–) or NH(4)(+) nutrition on energy production remain unresolved, this study was conducted to investigate the role of N source on group VII transcription factors, fermentative genes, energy metabolism and respiration under normoxic and hypoxic conditions. METHODS: We used Arabidopsis plants grown on Hoagland medium with either NO(3)(–) or NH(4)(+) as a source of N and exposed to 0.8 % oxygen environment. In both roots and seedlings, we investigated the phytoglobin–nitric oxide cycle and the pathways of fermentation and respiration; furthermore, NO levels were tested using a combination of techniques including diaminofluorescein fluorescence, the gas phase Griess reagent assay, respiration by using an oxygen sensor and gene expression analysis by real-time quantitative reverse transcription–PCR methods. KEY RESULTS: Under NO(3)(–) nutrition, hypoxic stress leads to increases in nitrate reductase activity, NO production, class 1 phytoglobin transcript abundance and metphytoglobin reductase activity. In contrast, none of these processes responded to hypoxia under NH(4)(+) nutrition. Under NO(3)(–) nutrition, a decreased total respiratory rate and increased alternative oxidase capacity and expression were observed during hypoxia. Data correlated with decreased reactive oxygen species and lipid peroxidation levels. Moreover, increased fermentation and NAD(+) recycling as well as increased ATP production concomitant with the increased expression of transcription factor genes HRE1, HRE2, RAP2.2 and RAP2.12 were observed during hypoxia under NO(3)(–) nutrition. CONCLUSIONS: The results of this study collectively indicate that nitrate nutrition influences multiple factors in order to increase energy efficiency under hypoxia.