Mechanism of Calcium Lactate Facilitating Phytic Acid Degradation in Soybean during Germination

Stimulation of soy seeds using environmentally friendly magnetic and electric fields

The study analyses the impact of alternating (magnetic induction B = 30 mT for t = 60 s) and constant magnetic fields (B = 130 mT for t = 17 h) and alternating electric fields (electric current E = 5 kV/cm for t = 60 s) on various growth parameters of soy plants: the germination energy and capacity, plants emergence, the fresh mass of seedlings, protein content (Kjeldahl's method), and photosynthetic parameters (with MINI-PAM 2000 WALTZ Photosynthesis Yield Analyser and a SPAD-502 Chlorophyll Meter). Four cultivars were used: MAVKA, MERLIN, VIOLETTA, and ANUSZKA. Moreover, the advanced Machine Learning processing pipeline was proposed to distinguish the impact of physical factors on photosynthetic parameters. The use of electromagnetic fields had a positive impact on the germination rate in MERLIN seeds. The best results in terms of germination improvement were observed for alternating magnetic field stimulation in all cultivars (p > 0.05). For the VIOLETTA cultivar an increase (p > 0.05) in the emergence and overall number of plants as well as fresh mass was observed after electromagnetic field stimulation. For the MAVKA and MERLIN cultivars, the concentration of proteins in the leaves was noticeably higher in plants grown from seeds stimulated using a constant magnetic field.

Exogenous methyl jasmonate combined with Ca2+ promote resveratrol biosynthesis and stabilize sprout growth for the production of resveratrol-rich peanut sprouts

Promoting resveratrol accumulation in plants and utilizing resveratrol-rich plants as raw materials for the development of functional foods is a promising development direction. The effects of methyl jasmonate (MeJA), in combination with CaCl2 and Ca2+ inhibitors, on physiological metabolism and resveratrol enrichment of peanut sprouts were investigated. MeJA combined with CaCl2 increased Ca2+ content, calmodulin content, and Ca2+- adenosine triphosphatase activity, as well as upregulated calcium-binding proteinase expression levels. Treatment with MeJA plus CaCl2 significantly increased peroxidase and superoxide dismutase activities and antioxidant capacities, significantly decreased the content of malondialdehyde and hydrogen peroxide, which resulted in a significantly increased in sprout length and fresh weight, and alleviated the inhibition of sprout growth. MeJA plus CaCl2 significantly increased the activities of phenylalanine ammonia-lyase and 4-coumarate coenzyme A ligase and upregulated the expression levels of phenylalanine ammonia-lyase, cinnamic acid 4-hydroxylase, and resveratrol synthase, thus significantly increasing resveratrol content. However, MeJA combined with Ca2+ antagonists reversed these effects. These results indicate that MeJA interacts with Ca2+ to promote resveratrol synthesis in peanut sprouts and to improve sprout stress tolerances.

CaCl2 promotes the cross adaptation of Reaumuria trigyna to salt and drought by regulating Na+, ROS accumulation and programmed cell death

Reaumuria trigyna, a salt-secreting xerophytic shrub endemic to arid desert regions of northwest China, is extremely adaptable to salt and aridity. In this study, we used PEG to simulates drought stress and investigated the effect of NaCl and CaCl₂ on R. trigyna seedlings exposed to drought stress. Exogenous application moderate NaCl and CaCl₂ were found to stimulate the growth and alleviate drought stress in R. trigyna seedlings. Moderate NaCl and CaCl₂ combined treatment increased fresh weight and decreased electrolyte leakage, and malondialdehyde (MDA) content in R. trigyna seedlings under drought stress. Simultaneously, leaf senescence and root damage induced by drought stress were alleviated, with programmed cell death (PCD) related genes expression down-regulated. Among them, the application of CaCl₂ under drought and salt treatment is the most effective way to increase osmotic regulators content, antioxidant enzymes activities, and related genes expressions of plants under drought stress, which scavenged excess reactive oxygen species (ROS) and alleviated oxidative damage caused by drought stress. Meanwhile, CaCl₂ can reduce the content of Na⁺and the ratio of Na⁺/K⁺ by promoting the outflow of Na⁺ and inflow of Ca²⁺, as well as the expression of ion transporter gene, and reduce the ionic toxicity caused by drought and salt cross adaptation. The principal component analysis (PCA) showed that the relevant beneficial indicators were positively correlated with the combined treatment. These results indicated that moderate NaCl can positively regulates defense response to drought stress in R. trigyna, while CaCl₂ can significantly promote this process.

Effects of Phytic Acid-Degrading Bacteria on Mineral Element Content in Mice

Trace minerals are extremely important for balanced nutrition, growth, and development in animals and humans. Phytic acid chelation promotes the use of probiotics in nutrition. The phytic acid-degrading strain Lactococcus lactis psm16 was obtained from swine milk by enrichment culture and direct plate methods. In this study, we evaluated the effect of the strain psm16 on mineral element content in a mouse model. Mice were divided into four groups: basal diet, 1% phytic acid, 1% phytic acid + psm16, 1% phytic acid + 500 U/kg commercial phytase. Concentrations of acetic acid, propionic acid, butyric acid, and total short-chain fatty acids were significantly increased in the strain psm16 group compared to the phytic acid group. The concentrations of copper (p = 0.021) and zinc (p = 0.017) in liver, calcium (p = 0.000), manganese (p = 0.000), and zinc (p = 0.000) in plasma and manganese (p = 0.010) and zinc (p = 0.022) in kidney were significantly increased in psm16 group, while copper (p = 0.007) and magnesium (p = 0.001) were significantly reduced. In conclusion, the addition of phytic acid-degrading bacteria psm16 into a diet including phytic acid can affect the content of trace elements in the liver, kidney, and plasma of mice, counteracting the harmful effects of phytic acid.

Spermidine improves antioxidant activity and energy metabolism in mung bean sprouts

The effects of exogenous spermidine and dicyclohexylamine (DCHA, spermidine synthesis inhibitor) on the antioxidative system and energy status of germinating mung bean were investigated. Results showed that exogenous spermidine increased the content of total phenolic and ascorbic acid and the antioxidative activity, but reduced activities and gene expressions of peroxidase (POD) and catalase (CAT). These changes might be explained by increased H₂O₂ content and activities of succinic dehydrogenase (SDH), adenosine triphosphatases (ATPases), and cytochrome c oxidase (CCO), resulting in higher adenosine triphosphate (ATP) and energy charge (EC). Interestingly, spermidine down-regulated expressions of SDH, H⁺-ATPase, Ca²⁺-ATPase and CCO whilst DCHA reduced energy metabolism and induced the opposite effects to spermidine, except for ascorbic acid content. Inhibition was reversed by exogenous spermidine. In conclusion, spermidine induced the accumulation of H₂O₂, enhanced the antioxidative system and improved the energy metabolism to enhance the functional quality of mung bean sprouts.

Isolation of phytase-producing yeasts from rice seedlings for prospective probiotic applications

The yeasts transmitted from seeds to sprouts might be used as probiotics for host plants. To investigate the inheritable yeasts of rice plants for probiotics, the fungal internal transcribed spacer (ITS) regions (ITS1 and ITS2) in rice sprouts were analyzed by Illumina-based sequencing. The fungal genera Candida, Mortierella, Alternaria, Penicillium, and Tomentella were revealed by both ITS1 and ITS2 sequence analysis. The endophytic yeasts were isolated from rice sprouts by yeast selective medium. Compared with the negative controls, inoculation of isolate Y3 released 2.2 folds higher concentration of free phosphate in soybean meal broth. Most of the phytase activities were located in the yeast cell interiors. The shoot lengths, shoot fresh weights, and root fresh weights of inoculated seedlings increased by 35%, 80%, and 60% compared with the control seedlings, respectively. The results suggested that the rice sprouts contained diverse phytase-producing yeasts transmitted from seeds. These yeasts might be adopted as prospective probiotics to improve rice growth by increasing phosphate utilization efficacy.

Inositol 1,4,5-Trisphosphate Mediates Nitric-Oxide-Induced Chilling Tolerance and Defense Response in Postharvest Peach Fruit

The function of inositol 1,4,5-trisphosphate (IP3) on nitric oxide (NO)-induced chilling tolerance and defense response in postharvest peach fruit was explored. The postharvest fruit were treated with sodium nitroprusside (SNP, exogenous NO donor), cPTIO (NO scavenger), and neomycin (IP3 inhibitor). It turned out that SNP treatment mitigated chilling injury (CI) and stimulated NO accumulation in postharvest peach fruit. Further, SNP enhanced phosphoinositide-specific phospholipase C (PI-PLC) activity and, thereby, stimulated IP3 prodution. SNP also upregulated the activity and expression of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), glutathione S-transferase (GST), and glutathione reductase (GR). In addition, SNP enhanced the expression of small ubiquitin-like modifier (SUMO) and methionine sulfoxide reductase (MSR) and weakened the activity and expression of lipoxygenase (LOX) and phospholipase D (PLD). These above impacts stimulated by SNP treatment were blocked by the addition of cPTIO and neomycin. Overall, IP3 was involved in NO-enhanced chilling tolerance and defense response in postharvest peach fruit.

Effects of exogenous Ca2+ on phenolic accumulation and physiological changes in germinated wheat (Triticum aestivum L.) under UV-B radiation

Exogenous Ca²⁺ affects the phenolic metabolism and physiological indices of germinated wheat under ultraviolet-B (UV-B) radiation, but the mechanism is unclear. The current study applied exogenous Ca²⁺ and Ca²⁺ channel blocker LaCl₃ to the germinated wheat under UV-B radiation to unravel the role of Ca²⁺. The results indicated that total phenolic content (TPC) of the 4-day germinated wheat under UV-B radiation with CaCl₂ (UV-B+Ca) treatment significantly increased by 10.3% as compared to the UV-B treatment. Gene expression levels of p-coumarate 3-hydroxylase, cinnamic acid 4-hydroxylase and caffeic acid O-methyltransferase were positively correlated with the content of ferulic and p-coumaric acids, respectively. Exogenous Ca²⁺ could significantly alleviate the membrane lipid peroxidation, activate the antioxidant enzymes and regulate the phytohormone level under UV-B radiation. This study suggested that exogenous Ca²⁺ participated in the phenolic metabolism and physiological regulation in germinated wheat under UV-B radiation.

iTRAQ-based proteomic analysis reveals changes in response to UV-B treatment in soybean sprouts

It has been shown that 15 μW·cm-2 UV-B radiation has the most pronounced effects on γ-aminobutiric acid (GABA), inositol 1,4,5-trisphosphate (IP3) and abscisic acid (ABA) accumulation in 4-day-old soybean sprouts. Nevertheless, its mechanism of action, from the perspective of protein expression, remains largely unknown. In this study, isobaric tags for relative and absolute quantitation (iTRAQ) were employed to investigate UV-B treatment-induced proteomic changes in soybean sprouts. Results showed that UV-B treatment effectively regulated proteins involved in GABA biosynthesis, such as glutamate synthase, glutamate decarboxylase (GAD), methionine synthetase, 5-methyltetrahydropteroyltriglutamate--homocysteine methyltransferase, aminoaldehyde dehydrogenase (AMADH) and inositol phosphate metabolism pathways, including phosphoinositide phospholipase C (PI-PLC), purple acid phosphatase (PAP) and inositol polyphosphate 5-phosphatase. In addition, proteins involved in ABA biosynthesis and signal transduction, such as 9-cis-epoxycarotenoid dioxygenase (NCED), abscisic-aldehyde oxidase (AO), SNF1-related protein kinase (SnRK), protein phosphatase 2C (PP2C), guanine nucleotide-binding protein and calreticulin-3, were also modulated under UV-B treatment.

iTRAQ-based analysis of proteins involved in secondary metabolism in response to ABA in soybean sprouts

Abscisic acid (ABA), as a sesquiterpenoid hormone, could regulate lots of physiological processes, especially secondary metabolism in plants. Nevertheless, its mechanism of action, from the perspective of protein expression, remains largely unknown. In the study, isobaric tags for relative and absolute quantitation (iTRAQ) was employed to investigate ABA treatment-induced proteomic changes related to secondary metabolism in soybean sprouts. Among the 3033 proteins identified, compared with the control, ABA treatment up- and down-regulated 350 proteins. These proteins were involved in GABA biosynthesis, such as glutamate synthase, glutamate decarboxylase (GAD), methionine synthetase, 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase 1, aminoaldehyde dehydrogenase (AMADH) and inositol phosphate metabolism pathways, including phosphoinositide phospholipase C (PI-PLC), purple acid phosphatase (PAP) and inositol polyphosphate 5-phosphatase. In addition, flavonoid biosynthetic proteins, such as cinnamate 4-hydroxylase, chalcone isomerase, chalcone synthase, isoflavone synthase and isoflavone reductase, were also modulated in response to ABA treatment. What's more, ABA treatment regulated proteins involved in ABA signal transduction, such as SNF1-related protein kinase (SnRK), protein phosphatase 2C (PP2C), guanine nucleotide-binding protein and calreticulin-3.

Polyamines regulating phytic acid degradation in mung bean sprouts

BACKGROUND

Polyamines are essentially involved in cell division and differentiation. Transport of polyamines is adenosine triphosphate (ATP)-dependent, while phytic acid is the major reserve of phosphate essential to the energy-producing machinery of cells. Thus polyamines might enhance phytic acid degradation during mung bean germination. In this study, different polyamines (putrescine (Put), spermidine (Spd) and spermine (Spm)) and dicyclohexylamine (DCHA, an inhibitor of Spd synthesis) were applied to investigate the function of polyamines on phytic acid degradation.

RESULTS

Spd exhibited the best effect at the same concentration. Simultaneously, exogenous Spd improved sprout growth and enhanced the accumulation of gibberellin acid 3 (GA₃ ), indole-3-acetic acid (IAA), abscisic acid (ABA) and cytokinin (CTK). This must be due to the increased endogenous polyamine contents. Apart from dramatically reducing phytic acid content, Spd resulted in the up-regulation of PA, PAP, MIPP and ALP transcript levels and the enhancement of phytase and acid phosphatase activities. However, DCHA application caused the opposite results, because it decreased endogenous polyamine contents. Furthermore, Spd alleviated the DCHA-induced inhibitory effect to some extent.

CONCLUSION

Overall, polyamines, especially Spd, could accelerate phytic acid degradation in mung bean sprouts by inducing the synthesis of endogenous polyamines and phytohormones and enhancing the growth of sprouts. © 2017 Society of Chemical Industry.

Ca2+ influxes and transmembrane transport are essential for phytic acid degradation in mung bean sprouts

BACKGROUND

Phytic acid is considered as an antinutrient. Ca²⁺ addition during germination has been proved to be an effective method for reducing phytic acid content in seeds. In this study, mung bean sprouts were treated with LaCl₃ (La), verapamil (VP), ruthenium red (RR), and CaCl₂ to explore the effect of Ca²⁺ influxes on phytic acid degradation.

RESULTS

CaCl₂ (6 mmol L^-1 ) significantly improved extracellular and intracellular calcium precipitates and calcium content, elevated phytase and acid phosphatase activity, and further enhanced phytic acid degradation. Conversely, La, VP, or RR induced the opposite results. Among them, RR exhibited the most significant inhibitory effect. Decreased PA, PAP, MIPP, and ALP gene expression after VP or RR treatment was also observed. Enhanced or weakened extracellular Ca²⁺ influx or intracellular Ca²⁺ efflux was detected with increased or decreased calcium precipitates distributed in different compartments. However, CaCl₂ addition differentially reversed the inhibitory effects of all channel blockers.

CONCLUSION

CaCl₂ enhanced Ca²⁺ influxes and accumulation in cells, which contributed to the regulation of phytic acid degradation. This study demonstrates that calcium channels play an essential role in mediating phytic acid degradation in mung bean sprouts, and both extracellular and intracellular Ca²⁺ -regulation were involved in phytic acid degradation. © 2017 Society of Chemical Industry.

Gibberellic acid promoting phytic acid degradation in germinating soybean under calcium lactate treatment

BACKGROUND

Phytic acid as a phosphorus storage vault provides phosphorus for plant development. It is an anti-nutritional factor for humans and some animals. However, its degradation products lower inositol phosphates have positive effects on human health. In this study, the effect of gibberellic acid (GA) on phytic acid degradation under calcium lactate (Ca) existence was investigated.

RESULTS

The results showed that Ca + GA treatment promoted the growth status, hormone metabolism and phytic acid degradation in germinating soybean. At the same time, the availability of phosphorus, the activity of phytic acid degradation-associated enzyme and phosphoinositide-specific phospholipase C (PI-PLC) increased. However, the relative genes expression of phytic acid degradation-associated enzymes did not vary in accordance with their enzymes activity.

CONCLUSION

The results revealed that GA could mediate the transport and function of calcium and a series of physiological and biochemical changes to regulate phytic acid degradation of soybean sprouts. © 2017 Society of Chemical Industry.

IP3 Mediates Nitric Oxide-Guanosine 3',5'-Cyclic Monophosphate (NO-cGMP)-Induced Isoflavone Accumulation in Soybean Sprouts under UV-B Radiation

In this study, to investigate the role of inositol 1,4,5-trisphosphate (IP3) in nitric oxide-guanosine 3',5'-cyclic monophosphate (NO-cGMP)-induced isoflavone accumulation in soybean sprouts under UV-B radiation, the sprouts were treated with donors and inhibitors of NO and cGMP as well as IP3 inhibitor. Results showed that NO, with cGMP as a second messenger, stimulates IP3 accumulation under UV-B radiation. Consistent with the increase in IP3 content, the up-regulation of gene and protein expression of phosphoinositide-specific phospholipase C (PI-PLC) in response to sodium nitroprusside (SNP) (exogenous NO donor) and 8-Br-cGMP (cGMP analogue) was also observed. In addition, protein kinase G (PKG) participated in NO-cGMP-induced IP3 production. IP3 induced by the NO-cGMP pathway was involved in isoflavone synthesis by elevating the activity and gene and protein expressions of chalcone synthase (CHS) and isoflavone synthase (IFS). Overall, IP3 mediates NO-cGMP-induced isoflavone accumulation in soybean sprouts under UV-B stress.