Malic Content Research Articles

A Graminaceae-derived protein hydrolysate and its fractions provide differential growth and modulate qualitative traits of lettuce grown under non-saline and mild salinity conditions

The modulation of plant secondary metabolism by the manipulation of nutrient solution (NS) electrical conductivity and biostimulant application has the potential to increase crop growth and the content of bioactive compounds, thus ameliorating the qualitative attributes of vegetables. A Graminaceae-derived protein hydrolysate (pH) and its molecular fractions PH1 (>10 kDa), PH2 (1 < x <10 kDa) and PH3 (<1 kDa) were applied on lettuce grown in a soilless system and irrigated with two levels of NaCl in the NS (0 and 30 mM). The different pH fractions provided distinct responses, with PH2 in saline conditions increasing lettuce fresh weight by 10.48%, and decreased Na, Cl, malate and citrate concentrations in the leaves by 37.24%, 15.45%,31.4% and 33.73% compared to control. Similar results were achieved by the fraction PH3. However, pH and its fractions PH2 and PH3 increased total flavonoids in salinity conditions, while pH and its fraction PH3 increased total phenolic acids in both saline and non-saline conditions. At the same time, all the 3 fractions of pH increased lutein in both conditions. Therefore, pH fractions should be casted, under tailored conditions, to achieve the desired growth and modulation of qualitative attributes. Nonetheless, omic approaches should be further recommended to support and clarify the mechanisms of these fractions.

Regulation of NADP-Malic Enzyme Activity in Maize (Zea mays L.) under Salinity with Reference to Light and Darkness.

We revealed the functional characterization of C4-NADP-malic enzyme (NADP-ME), extracted and partially purified from maize (Zea mays L. cv. Kaveri 50). The leaf discs were previously activated under 1000-1200 µE m-2 s-1, incubated in bicarbonate (2.0 mM) solution, and subjected to salt stress (100 mM NaCl). Initially, salt stress was evident from the accumulations of proline, chlorophyll content, carbohydrate profile, and Hill activity influencing the C4 enzyme. Primarily, in illuminated tissues, the activity of the enzyme recorded a reduced trend through salinity irrespective of light and darkness compared to the control. On illumination, the kinetic parameters such as Vmax of the enzyme increased by 1.36-fold compared to in the dark under salinity whereas Km was decreased by 20% under the same condition. The extent of light induction was proportionate to limiting (0.01 mM) and saturated (4.0 mM) malate concentrations for enzyme activity. Moreover, the catalytic properties of the enzyme were also tested on concomitant responses to activator (citrate and succinate) and inhibitor (oxalate and pyruvate) residues. The sensitivity to light and dark effects was also tested for reducing agents such as dithiothreitol, suggesting the effect of the changes in redox on the regulatory properties of the enzyme. The ratio of enzyme activity under light and darkness in the presence or absence of a reducing agent was concomitantly increased with varying malate concentrations. At the molecular level, protein polymorphism of the enzyme represented minor variations in band intensities, however, not in numbers through salinity subjected to light and darkness. Therefore, salinity-induced changes in the decarboxylation reaction, evident by NADP-ME activity, may be based on the redox property of regulatory sites and sensitivity to light and darkness.

Infrared spectroscopy and biochemical parameters of rat tissues under heavy metal poisoning conditions

The increasing level of anthropogenic environmental pollution and effective means to reduce the negative impact of xenobiotics on animal and human health is an urgent problem today. Considering this, the purpose of the study is to examine the effect of heavy metals on accumulation processes under poisoning conditions, and biochemical parameters in the body of rats. Analogue groups were formed of rats of the same age, gender, and body weight to conduct the study. Rats were poisoned with solutions of copper sulfate, zinc sulfate, cadmium sulfate, and lead nitrate for 14 days. Using the method of infrared spectroscopy, substantial differences in the spatial structure of protein components in intact and poisoned animals were established. The difference between the spectral characteristics of the examined tissues is clearly demonstrated by the statistical indicators of skewness and kurtosis. It was determined that poisoning of rats with copper, zinc, cadmium, and lead ions affects the course of glycolysis reactions and the tricarboxylic acid cycle, which leads to a likely increase in serum concentrations of lactate and pyruvate, oxaloacetate and α-ketoglutarate and a decrease in Malate content compared to intact rats. It was established that under the conditions of poisoning, there is also a substantial increase (P &lt; 0.05) in the content of the examined heavy metals in the blood, liver, and kidneys. In animals poisoned with heavy metals, a decrease in the pool of free amino acids in the kidneys is observed. In particular, the content of aspartic acid, valine, glycine, tyrosine, and cystine (more than 1.5 times) in the kidneys of such rats decreases; alanine, leucine, serine, taurine, threonine, phenylalanine (more than 2.0 times), lysine – 3.4-4.9 times. Therewith, an increase in the level of isoleucine and methionine by 1.3-1.5 times, ornithine – by 1.8-2.1 times, and glutamic acid – by 4.4-5.3 times in rats of the experimental group compared to intact ones was identified. The results of the study can be helpful in the professional activities of doctors of veterinary medicine, toxicologists, biologists, and environmentalists and used to control the quality of livestock products, conduct toxicological studies, and analyse environmental objects

In Vivo Evaluation of Almotriptan malate Formulation through Intranasal Route for the Treatment of Migraine: Systematic Development and Pharmacokinetic Assessment.

Migraine headaches are usually intolerable, and a quick-relief treatment remains an unmet medical need. Almotriptan malate is a serotonin (5-HT1B/1D) receptor agonist approved for the treatment of acute migraine in adults. It is currently available in an oral tablet dosage form and has a Tmax of 1-3h, and therefore, there is a medical need to develop a non-invasive rapidly acting formulation. We have developed an intranasal formulation of almotriptan malate using the quality-by-design (QbD) approach. A 2-factor 3-level full factorial design was selected to build up the experimental setting. The developed formulation was characterized for pH, viscosity, in vitro permeation, ex vivo permeation, and histopathological tolerance. To assess the potential of the developed formulation to produce a rapid onset of action following intranasal delivery, a pharmacokinetic study was performed in the Sprague-Dawley rat model and compared to the currently available marketed oral tablet formulation. For this, the LC-MS/MS bioanalytical method was developed and used for the determination of plasma almotriptan malate concentrations. Results of a pharmacokinetic study revealed that intranasal administration of optimized almotriptan malate formulation enabled an almost five-fold reduction in Tmax and about seven-fold increase in bioavailability in comparison to the currently available oral tablet formulation, suggesting the potential of developed almotriptan malate intranasal formulation in producing a rapid onset of action as well as enhanced bioavailability.

Identification of co-expressed networks and key genes associated with organic acid in peach fruit

• The number of DEGs increased along with fruit development taking stage 1 as control. • Transcription factors play crucial role during organic acid accumulation in fruit. • Hydrogen ion transportation contributes to organic acid accumulation. Malate, citrate, and quinate are the major organic acids in ripen peach fruit, the content of which undergoes considerable variations during fruit development and maturation. The molecular mechanisms underlying these variations remain largely unclear. In this study, weighted gene co-expression network analysis (WGCNA) of two accessions in five developmental stages was performed to identify networks and key genes associated with main organic acids. The obtained hubgenes were screened by comparative transcriptome analysis of 102 peach accessions. Combined with functional annotation, three genes encoding WRKY50, MYB62, and cation/H+ exchanger 18, respectively, were detected as candidate genes related with malate content. One gene encoding bHLH1 was considered as candidate genes associated with citrate content. The four candidate genes were validated by integrated analysis of phenotype and expression analysis of ‘Jintong 5’, a randomly selected accession. These findings provide new sight to our existing knowledge of organic acid regulation in peach.

THE IMPACT OF HORMONE-VITAMIN COMPLEX ON FUNCTIONAL ACTIVITY OF THE MUSCLE TISSUE OF DESCENDANTS OF IRRADIATED ANIMALS.

The aim: To determine the hormone-vitamin complex impact on the terminal links of glycolysis, the tricarboxylic acids cycle, and the initial stage of glucone¬ogenesis in the muscle tissue in descendants of irradiated animals. Materials and methods: Pyruvate kinase, lactate dehydrogenase, malate dehydrogenase, NADP-dependent malate dehydrogenasee and phosphoenolpyruvate carboxykinase activities, the content of lactate, pyruvate, malate and oxaloacetate were determined in the blood, myocardium and thigh muscles of 66 rats after exposure to ionizing gamma-radiation. Rats were injected by a hormone-vitamin complex which efficacy was determined using the abovementioned indexes. Results: Hormone-vitamin complex administration to descendants of irradiated animals exposed to 1.0 Gy results to pyruvate kinase activity increase in the myocardium and skeletal muscles of descendants from animals irradiated by 0.5 Gy and exposed to 1.0 Gy irradiation. Blood serum pyruvate kinase activity in descendants from animals irradiated by 1.0 Gy and exposed to 1.0 Gy radiation after the pharmacological correction was higher compared with the same index before pharmacological correction. The lactate dehydrogenase activity in the myocardium, skeletal muscles and blood in descendants born from animals irradiated by maximal dose exposed to 1.0 Gy radiation was less in these tissues after pharmacological correction. Conclusions: The hormone-vitamin complex use in the descendants of irradiated animals led to muscle tissue energy resources improvement. Our data are the experimental background for theoriginal hormone-vitamin complex efficacy further evaluation in the aspect of vital organs and body systems functional activity restoration under the influence of ionizing radiation.

Physiological and transcriptome analyses of the effects of excessive water deficit on malic acid accumulation in apple.

Acidity is a determinant of the organoleptic quality of apple, whereas its regulatory mechanism under water stress remains obscure. Fruit from apple 'Yanfu 3' of Fuji trees grown under normal water irrigation (CK), excessive water deficit treatment (DRT) and excessive water irrigation treatment (WAT) were sampled at 85, 100, 115, 130, 145, 160 and 175days after full bloom designated stages S1, S2, S3, S4, S5, S6 and S7, respectively. DRT treatment reduced the individual fruit weight and fruit moisture content, and increased fruit firmness. The malate content of DRT treatment was higher than that of CK and WAT from stages S1 to S7. RNA sequencing (RNA-seq) analysis of the transcriptome at stages S4, S6 and S7 indicated that malate anabolism was associated with cysteine and methionine, auxin signaling, glyoxylate and dicarboxylate and pyruvate metabolism. Overexpression of MdPEPC4 increased the malate content in apple calli induced by 4% PEG. Our study provides novel insights into the effects of water stress on the molecular mechanism underlying apple fruit acidity.

Long-Chain and Medium-Chain Fatty Acids in Energy Metabolism of Murine Kidney Mitochondria

Scientists have long established that fatty acids are the primary substrates for kidney mitochondria. However, to date we still do not know how long-chain and middle-chain fatty acids are oxidized at the mitochondrial level. Our previous research has shown that mitochondria from the heart, brain, and kidney oxidize palmitoylcarnitine at a high rate only in the presence of succinate, glutamate, or pyruvate. In this paper, we report properties of the isolated kidney mitochondria and how malate and succinate affect the oxidation of C16 and C8 acylcarnitines. The isolated kidney mitochondria contain very few endogenous substrates and require malate to oxidize pyruvate, glutamate, and C16 or C8 acylcarnitines. We discovered that with 10 µM of C16 or C8 acylcarnitines, low concentrations of malate (0.2 mM) or succinate (0.5 mM) enhance the States 4 and 3 respiratory rates several times. The highest respiration rates were observed with C16 or C8 acylcarnitines and 5 mM succinate mixtures. Results show that kidney mitochondria, unlike the heart and brain mitochondria, lack the intrinsic inhibition of succinate dehydrogenase. Additionally, results show that the oxidation of fatty acid by the small respirasome's supercomplex generates a high level of CoQH2, and this makes SDH in the presence of succinate reverse the flow of electrons from CoQH2 to reduce fumarate to succinate. Finally, we report evidence that succinate dehydrogenase is a key mitochondrial enzyme that allows fast oxidation of fatty acids and turns the TCA cycle function from the catabolic to the anabolic and anaplerotic metabolic pathways.

Ocean acidification causes fundamental changes in the cellular metabolism of the Arctic copepod Calanus glacialis as detected by metabolomic analysis

Using a targeted metabolomic approach we investigated the effects of low seawater pH on energy metabolism in two late copepodite stages (CIV and CV) of the keystone Arctic copepod species Calanus glacialis. Exposure to decreasing seawater pH (from 8.0 to 7.0) caused increased ATP, ADP and NAD+ and decreased AMP concentrations in stage CIV, and increased ATP and phospho-L-arginine and decreased AMP concentrations in stage CV. Metabolic pathway enrichment analysis showed enrichment of the TCA cycle and a range of amino acid metabolic pathways in both stages. Concentrations of lactate, malate, fumarate and alpha-ketoglutarate (all involved in the TCA cycle) increased in stage CIV, whereas only alpha-ketoglutarate increased in stage CV. Based on the pattern of concentration changes in glucose, pyruvate, TCA cycle metabolites, and free amino acids, we hypothesise that ocean acidification will lead to a shift in energy production from carbohydrate metabolism in the glycolysis toward amino acid metabolism in the TCA cycle and oxidative phosphorylation in stage CIV. In stage CV, concentrations of most of the analysed free fatty acids increased, suggesting in particular that ocean acidification increases the metabolism of stored wax esters in this stage. Moreover, aminoacyl-tRNA biosynthesis was enriched in both stages indicating increased enzyme production to handle low pH stress.

New Insights into MdSPS4-Mediated Sucrose Accumulation under Different Nitrogen Levels Revealed by Physiological and Transcriptomic Analysis.

Nitrogen nutrition participates in many physiological processes and understanding the physiological and molecular mechanisms of apple responses to nitrogen is very significant for improving apple quality. This study excavated crucial genes that regulates sugar metabolism in response to nitrogen in apples through physiology and transcriptome analysis, so as to lay a theoretical foundation for improving fruit quality. In this paper, the content of sugar and organic acid in apple fruit at different developmental periods under different nitrogen levels (0, 150, 300, and 600 kg·hm-2) were determined. Then, the transcriptomic analysis was performed in 120 days after bloom (DAB) and 150 DAB. The results showed that the fructose and glucose content were the highest at 120 DAB under 600 kg·hm-2 nitrogen level. Meanwhile, different nitrogen treatments decreased malate content in 30 and 60 DAB. RNA-seq analysis revealed a total of 4537 UniGenes were identified as differentially expressed genes (DEGs) under nitrogen treatments. Among these DEGs, 2362 (52.06%) were up-regulated and 2175 (47.94%) were down-regulated. The gene co-expression clusters revealed that most DEGs were significantly annotated in the photosynthesis, glycolysis/gluconeogenesis, pyruvate metabolism, carbon metabolism, carbon fixation in photosynthetic organisms and plant hormone signal transduction pathways. The key transcription factor genes (ERF, NAC, WRKY, and C2H2 genes) were differentially expressed in apple fruit. Sugar and acid metabolism-related genes (e.g., HXK1, SPS4, SS2, PPC16-2, and MDH2 genes) exhibited significantly up-regulated expression at 120 DAB, whereas they were down-regulated at 150 DAB. Furthermore, the MdSPS4 gene overexpression positively promoted sucrose accumulation in apple callus and fruit. In conclusion, the combinational analysis of transcriptome and the functional validation of the MdSPS4 gene provides new insights into apple responses to different nitrogen levels.

Low-acidity ALUMINUM-DEPENDENT MALATE TRANSPORTER4 genotype determines malate content in cultivated jujube.

Jujube (Ziziphus jujuba Mill.), the most economically important fruit tree in Rhamnaceae, was domesticated from sour jujube (Z. jujuba Mill. var. spinosa (Bunge) Hu ex H.F.Chow.). During domestication, fruit sweetness increased and acidity decreased. Reduction in organic acid content is crucial for the increase in sweetness of jujube fruit. In this study, the determination of malate content among 46 sour jujube and 35 cultivated jujube accessions revealed that malate content varied widely in sour jujube (0.90-13.31 mg g-1) but to a lesser extent in cultivated jujube (0.33-2.81 mg g-1). Transcriptome sequencing analysis showed that the expression level of Aluminum-Dependent Malate Transporter 4 (ZjALMT4) was substantially higher in sour jujube than in jujube. Correlation analysis of mRNA abundance and fruit malate content and transient gene overexpression showed that ZjALMT4 participates in malate accumulation. Further sequencing analyses revealed that three genotypes of the W-box in the promoter of ZjALMT4 in sour jujube associated with malate content were detected, and the genotype associated with low malate content was fixed in jujube. Yeast one-hybrid screening showed that ZjWRKY7 binds to the W-box region of the high-acidity genotype in sour jujube, whereas the binding ability was weakened in jujube. Transient dual-luciferase and overexpression analyses showed that ZjWRKY7 directly binds to the promoter of ZjALMT4, activating its transcription, and thereby promoting malate accumulation. These findings provide insights into the mechanism by which ZjALMT4 modulates malate accumulation in sour jujube and jujube. The results are of theoretical and practical importance for the exploitation and domestication of germplasm resources.

Effects of Nitrogen Deficiency on the Metabolism of Organic Acids and Amino Acids in Oryza sativa.

Organic acids metabolism and nitrogen (N) metabolism in rice seedlings and the relationship between them are not fully understood. In this study, rice (Oryza sativa L. ssp. Indica) variety “Huanghuazhan” was used as the experimental material, and three N levels (5 mM, 1 mM, and 0 mM NH4NO3) were set by the hydroponic method for different levels of N treatment. Our results showed that the increased content of malate in rice leaves caused by reducing N level was related to the increased synthesis of malate (the activity of leaf PEPC increased)and the decreased degradation of malate (the activity of leaf NADP-ME decreased), while the increased contents of citrate and isocitrate in rice leaves caused by reducing N level might not be caused by the increased biosynthesis, but due to the decrease in degradation of citrate and isocitrate (the activities of leaf CS, ACO, and NADP-IDH decreased). The increased content of malate in rice roots caused by reducing N level might be related to the increased biosynthesis and the decreased degradation of root malate (the activities of root NAD-MDH and PEPC increased, while the activity of NADP-ME decreased). Compared to the control (5 mM NH4NO3), the increased content of citrate in rice roots caused by reducing N level might be related to the increased biosynthesis rather than the decreased degradation of citrate, due to the higher activities of CS and ACO in rice roots under 0 mM N and 1mM N treatment when compared to that of the control ones. At the same time, the increased content of isocitrate in roots was related to the increased isomerization of isocitrate (the activity of root ACO increased) and the decreased degradation of isocitrate (the activity of root NADP-IDH decreased). With the reducing N level, the activities of N metabolism-related enzymes, such as nitrate reductase (NR), glutamine synthetase (GS), and glutamate synthase (GOGAT), decreased in rice leaves and roots, resulting in the decreased contents of total free amino acids (TFAAs) and soluble proteins in rice seedlings, and finally led to the growth inhibition. Our results showed that the dynamics of organic acids metabolism caused by reducing N level were different in rice leaves and roots. In conclusion, there was a close correlation between organic acids metabolism and N metabolism in rice leaves and roots under N-limited conditions; furthermore, such a correlation was more obvious in rice leaves than that of roots.

Geobacter sulfurreducens metabolism at different donor/acceptor ratios.

Geobacter species have great application potential in remediation processes and electrobiotechnology. In all applications, understanding the metabolism will enable target‐oriented optimization of the processes. The typical electron donor and carbon source of the Geobacter species is acetate, while fumarate is the usual electron acceptor. Here, we could show that depending on the donor/acceptor ratio in batch cultivation of Geobacter sulfurreducens different product patterns occur. With a donor/acceptor ratio of 1:2.5 malate accumulated as an intermediate product but was metabolized to succinate subsequently. At the end of the cultivation, the ratio of fumarate consumed and succinate produced was approximately 1:1. When fumarate was added in excess, malate accumulated in the fermentation broth without further metabolization. After the addition of acetate to stationary cells, malate concentration decreased immediately and additional succinate was synthesized. Finally, it was shown that also resting cells of G. sulfurreducens could efficiently convert fumarate to malate without an additional electron donor. Overall, it was demonstrated that by altering the donor/acceptor ratio, targeted optimization of the metabolite conversion by G. sulfurreducens can be realized.

The isolated and combined impacts of ethanol and ethylene application on sugars and organic acids dynamics in ‘Elstar’ and ‘Nicoter’ apples

The aim was to evaluate the isolated or combined effects of ethanol vapor (500 ppm) and ethylene treatments (150 ppm), on the ethylene production, respiration, sugars and organic acids dynamics of ‘Elstar’ and ‘Nicoter’ apples after harvest, during 14 d at 20 °C. Another aim was to identify at which step of fruit metabolism ethanol vapor acts. Fruit were exposed to ethanol vapor and/or ethylene for 24 h. Metabolites were evaluated at 0, 7 and 14 d at 20 °C. Ethanol vapor treatment significantly inhibited the effect of ethylene on the ethylene production and respiration, but had no significant effect on the starch metabolization and sucrose dynamics. Its application also resulted in higher succinate, malate and total organic acids concentrations. Ethanol application reduced significantly the sucrose conversion to glucose and fructose, while the ethanol + ethylene treatment resulted in high total sugars, fructose and sorbitol concentration after 14 d at 20 °C. The ethanol application (500 ppm) also affected conversion of succinate to fumarate, suggesting the succinate dehydrogenase activity as one possible action point of ethanol on the apple fruit metabolism. According to the PCA analysis, the combination of ethanol + ethylene treatments had a different response as their isolated application, affecting sugars and organic acids metabolism differently. Additionally, it can be verified that the response to treatments of both apple cultivars is differently affected by the holding time, being the response latter for ‘Nicoter’ apples when compared to ‘Elstar’.

Diversity in Acidity between Core and Pulp of Asian Pear Fruit Is Mainly Regulated by the Collaborative Activity of PH8.1 and DIC2 Genes during Fruit Development

The pear (Pyrus pyrifolia) is an important accessory fruit in which the pear core is tarter than the pear pulp. However, the reason for the acidic core and diversity in the taste of the same fruit is not clear. In this study, we observed that the citrate contents were three times higher in the core than in the pulp, while the malate content decreased along with fruit development and was significantly lower in the core than in the pulp at 110 days after flowering. Overall transcript levels for citrate-malate synthesis-related genes increased more in the pear core than the pulp at early fruit development, while degradation-related genes activity was nearly similar or non-significant between the core and pulp during fruit development. The lesser malate accumulation in the pear core compared to the pulp at 110 DAF was possibly due to the reduced activity of tDT2 gene. Regarding citrate accumulation, we identified five important p-type H+-ATPase genes in pear and found that the relative expression level of the PH8.1 gene was four-fold higher in the core than in the pulp during fruit development. Moreover, the expression level of di-carboxylate carrier gene 2 (DIC2) was constantly and significantly higher in the core than in the pulp. In addition, correlation analysis signified that the transcript levels of the two genes PH8.1 and DIC2 positively and significantly correlated with the citrate contents. These results suggested that the increased and collaborative activity of PH8.1 and DIC2 played a key role in the higher citrate accumulation in the core than the pulp, thus, with the help of molecular breeding tools, the citrate contents can be optimized in pear fruit for divers and improved fruit flavoring.

Molecular elucidation for the variance of organic acid profile between citrus top and bottom canopy fruits

Organic acids are key metabolites for diverse fruit flavoring and vital for fruit quality measures. Their contents are significantly varied regarding the canopy position. However, the underlying mechanism is still unclear. In this study by using Citrus raticulata cv. Bendizao as research material, a significant 2-fold increase in citrate content and a 2-fold decrease in malate content were noticed in bottom-canopy fruits subjected to less light and low temperature compared to top-canopy fruits. Moreover, transcript levels of genes like citrate synthase (CS1), aconitate hydratase genes (ACO1 and ACO2), NAD-dependent malic enzyme gene (NAD-ME) and malate dehydrogenase genes (MDH1 and MDH2) were significantly higher, while transcript levels of other genes such as citrate utilization genes (ACL2, ACL3 and ACO3), malate synthase gene (MS) and cytosolic NAD-dependent malate dehydrogenase gene (cytNAD-MDH) were significantly lower in bottom-canopy fruits compared to top-canopy fruits. Additionally, transcript levels of proton pump genes (CsPHs and VHA), two transporter genes (MATE and ALMT9), and four transcription factor genes (MYB73, Noemi, MYC-N, and bHLH) were significantly higher, while mRNA levels of two transcription factor genes (MYB10 and WRKY14) and transporter genes (CsCit1 and ALMT9-like) were significantly lower in bottom-canopy fruits than those in top-canopy fruits. Taken together, the variance of organic acid profiles in the canopy could be attributed to the microclimate change, which comprehensively influences the organic acid accumulation-related genes’ transcript levels; reduced malate accumulation in bottom-canopy fruits is mainly due to the minimal expression of MS and cytNAD-MDH, and high expression of malate utilization genes (MDH and NAD-ME), while the higher citrate content in the bottom-canopy fruits is probably due to the enhanced vacuolar storage through increasing vacuolar proton pump genes and MATE transcript levels, and the minimal citrate degradation and efflux through decreasing ACL2, ACL3, ACO3 and CsCit1 transcript levels.

Responses of photosynthetic characteristics of oat flag leaf and spike to drought stress.

Raising crops production via improving photosynthesis has always been focused. Recently excavating and increasing the photosynthetic capacity of non-leaf organs becomes an important approach to crops yield increase. Here we studied the photosynthetic characteristics of the flag leaf and the non-leaf organs including the sheath, the glume and the lemma under greenhouse. The relative water content (RWC), the stomatal characteristics, the photosynthetic pigment contents, the enzyme activities in C3 and C4 pathway and the malate content of the flag leaf and the non-leaf organs on 7, 14, 21, and 28 days after anthesis (denoted by 7DAA, 14DAA, 21DAA, and 28DAA) were determined under well-watered (CK) and water-stressed (D) treatments. Drought stress significantly reduced the RWC of the flag leaf and the non-leaf organs, while the variation of RWC in the glume and the lemma was lower than in the flag leaf. The chlorophyll a content, the chlorophyll b content, the total chlorophyll content and the xanthophyll content in the flag leaf were significantly decreased under D. However, drought stress significantly increased the photosynthetic pigment contents in the glume at the late stage (21DAA and 28DAA). In addition, the induced activities of PEPC, NADP-MDH, NADP-ME, NAD-ME, and PPDK in non-leaf organs under drought stress suggested that the C4 photosynthetic pathway in non-leaf organs compensated the limited C3 photosynthesis in the flag leaf. Non-leaf organs, in particular the glume, showed the crucial function in maintaining the stable photosynthetic performance of oat.

Optimizing the fermentation conditions of fermented goji using sensory analysis and the biomass of Lactiplantibacillus plantarum NCU137

The main objective of this study was to optimize the fermentation conditions of goji and to analyze the sugar, organic acid, amino acid, and flavor compounds before and after the fermentation of goji. Based on the single-factor experiment, orthogonal array design and the range analysis, the optimized conditions for fermented goji were 30% raw material concentration, 28 h fermentation time and 0.05% inoculum size, respectively. Under optimal conditions, the biomass of Lactiplantibacillus plantarum NCU137 and sensory score of fermented goji reached to 8.84 ± 0.05 log CFU/g and 81.3 ± 1.5, respectively. After fermentation, the content of malate, succinic acid, and lactate increased, while the content of pyruvate, glucose, fructose, and the overall free amino acid decreased. After fermentation, volatile components except for the phenols and acids are declining. This study would provide theoretical basis and experimental data for the industrialization of Lycium barbarum fermentation. Novelty impact statement After Lactiplantibacillus plantarum NCU137 fermentation, the contents of organic acids and total acidity acid in fermented goji significantly increased, which could inhibit microbiological spoilage and growth. Moreover, we get a delicious fermented goji juice through the optimization of fermentation conditions. Therefore, the data obtained in this study provides a better understanding of the effects of raw material content, fermentation time, and inoculum size on the quality of fermented goji, which would be very beneficial for the production of high-quality fermented goji for subsequent consumption.

Effect of copper stress on Phaseolus coccineus in the presence of exogenous methyl jasmonate and/or Serratia plymuthica from the Spitsbergen soil

Copper stress in the presence of exogenous methyl jasmonate and Serratia plymuthica in a complete trifactorial design with copper (0, 50 µM), methyl jasmonate (0, 1, 10 µM) and Serratia plymuthica (without and with inoculation) was studied on the physiological parameters of Phaseolus coccineus. Copper application reduced biomass and allantoin content, but increased chlorophyll and carotenoids contents as well as catalase and peroxidases activities. Jasmonate did not modify biomass and organic acids levels under copper treatment, but additional inoculation elevated biomass and content of tartrate, malate and succinate. Jasmonate used alone or in combination with bacteria increased superoxide dismutase activity in copper application. With copper, allantoin content elevated at lower jasmonate concentration, but with additional inoculation – at higher jasmonate concentration. Under copper stress, inoculation resulted in higher accumulation of tartrate, malate and citrate contents in roots, which corresponded with lower allantoin concentration in roots. Combined with copper, inoculation reduced catalase and guaiacol peroxidase activities, whereas organic acids content was higher. Under metal stress, with bacteria, jasmonate reduced phenolics content, elevated superoxide dismutase and guaiacol peroxidase activities. The data indicate that jasmonate and S. plymuthica affected most physiological parameters of P. coccineus grown with copper and revealed some effect on biomass.

Physiological and metabolic responses in broccoli plants fertilized with green manure

Grasses and legumes affect differently the amount of N in the soil over time, mainly due to the differences in the chemical characteristics of its mass. Changes in the availability of N influence the absorption and assimilation of N, which will influence physiological processes in the plants. The objective of this paper is to evaluate the changes in gas exchange, chlorophyll fluorescence and biochemical activity in leaves of broccoli grown under different green manure amendments. The experiment was designed in a complete randomized block design, using the mass of jack bean (JB) and millet (M) pure and in mixtures and one control, totaling six treatments: Control, 100JB, 75JB25M, 50JB50M, 25JB75M, 100M, with four replicates. The canopy area, N content, gas exchange, and biochemical analyzes were evaluated on the broccoli index leaf 40 days after broccoli transplantation. The higher ratio of jack bean, the higher the canopy area, the N content and the amino acid, protein and malate content, and lower starch content, possibly due to the higher N mineralization in this green manure.