Production Of Soluble Sugars Research Articles

Development and biochemical profile of Zingiber officinale under different population densities of Meloidogyne javanica

Ginger is a medicinal plant known for its aromatic, antioxidant, and pharmacological properties. This study aimed to examine the vegetative growth and biochemical profile of ginger exposed to Meloidogyne javanica at different initial inoculum levels. The experiment was conducted in a greenhouse using a completely randomized design. Treatments comprised 0, 2000, 4000, 6000, 8000, and 10,000 eggs of M. javanica and eight replications per treatment. At 70 days after inoculation, plants were harvested and evaluated for nematode parameters, vegetative growth, total phenolic compounds, gingerol content, antioxidant activity, and soluble sugars content. Total nematode number increased linearly as a function of initial inoculum level. The reproduction factor was greater than one (RF>1) in all treatments. Vegetative development, however, was not affected. The highest concentrations of total phenolics and gingerol were estimated to occur with initial inoculum levels of 4500 and 4000 eggs, respectively. Higher population levels (>6000 eggs) stimulated the production of soluble sugars in ginger rhizomes. Although increasing levels of M. javanica did not affect ginger vegetative development, it significantly altered biochemical parameters, such as total phenolic compounds, gingerol content, antioxidant activity, and soluble sugars content, proving that M. javanica influences the quality of ginger.

Characterization of a novel acidophilic, ethanol tolerant and halophilic GH12 β-1,4-endoglucanase from Trichoderma asperellum ND-1 and its synergistic hydrolysis of lignocellulosic biomass

A novel acidophilic GH5 β-1,4-endoglucanase (TaCel12) from Trichoderma asperellum ND-1 was efficiently expressed in Pichia pastoris (a 1.5-fold increase). Deglycosylated TaCel12 migrated as a single band (26.5 kDa) in SDS-PAGE. TaCel12 was acidophilic with a pH optimum of 4.0 and displayed great pH stability (>80 % activity over pH 3.0–5.0). TaCel12 exhibited considerable activity towards sodium carboxymethyl cellulose and sodium alginate with Vmax values of 197.97 μmol/min/mg and 119.06 μmol/min/mg, respectively. Moreover, TaCel12 maintained >80 % activity in the presence of 20 % ethanol and 4.28 M NaCl. Additionally, Mn2+, Pb2+ and Cu2+ negatively affected TaCel12 activity, while the presence of 5 mM Co2+ significantly increased the enzyme activity. Analysis of action mode revealed that TaCel12 required at least four glucose (cellotetraose) residues for hydrolysis to yield cellobiose and cellotriose. Site-directed mutagenesis results suggested that Glu133 and Glu217 of TaCel12 are crucial catalytic residues, with Asp116 displaying an auxiliary function. Production of soluble sugars from lignocellulose is a crucial step in bioethanol development, and it is noteworthy that TaCel12 could synergistically yield fermentable sugars from corn stover and bagasse, respectively. Thus TaCel12 with excellent properties will be considered a potential biocatalyst for applications in various industries, especially for lignocellulosic biomass conversion.

Improved production of recombinant β-mannanase (TaMan5) in Pichia pastoris and its synergistic degradation of lignocellulosic biomass.

Mannan, a highly abundant and cost-effective natural resource, holds great potential for the generation of high-value compounds such as bioactive polysaccharides and biofuels. In this study, we successfully enhanced the expression of constructed GH5 β-mannanase (TaMan5) from Trichoderma asperellum ND-1 by employing propeptide in Pichia pastoris. By replacing the α-factor with propeptide (MGNRALNSMKFFKSQALALLAATSAVA), TaMan5 activity was significantly increased from 67.5 to 91.7U/mL. It retained higher activity in the presence of 20% ethanol and 15% NaCl. When incubated with a high concentration of mannotriose or mannotetraose, the transglycosylation action of TaMan5 can be detected, yielding the corresponding production of mannotetraose or mannooligosaccharides. Moreover, the unique mechanism whereby TaMan5 catalyzes the degradation of mannan into mannobiose involves the transglycosylation of mannose to mannotriose or mannotetraose as a substrate to produce a mannotetraose or mannopentose intermediate, respectively. Additionally, the production of soluble sugars from lignocellulose is a crucial step in bioethanol development, and it is noteworthy that TaMan5 could synergistically yield fermentable sugars from corn stover and bagasse. These findings offered valuable insights and strategies for enhancing β-mannanase expression and efficient conversion of lignocellulosic biomass, providing cost-effective and sustainable approaches for high-value biomolecule and biofuel production.

Economic analysis of enzyme recycling during enzymatic hydrolysis of sugar beets for soluble sugars production

AbstractEnzymatic hydrolysis of sugar beets is an efficient alternative to conventional hot water extraction where overall soluble extraction is valued. The economic analysis of a sugar beet soluble sugar production plant was designed and developed using SuperPro Designer software. The commercial scale operation was sized to process 100 million metric ton (MT)/day of sugar beets. The base case process includes transportation, grinding, thermal pretreatment, enzymatic hydrolysis, solid–liquid separation, and evaporation. The final product from the model was assumed to be a sugar syrup stream at 65% total solids content. Since the breakeven selling price was sensitive to the cost of enzymes, alternative scenario A added an ultrafiltration unit operation to separate the enzymes and reuse them in subsequent batches of hydrolysis. Steam was another major contributor to the operating cost. Alternative scenario B included a natural gas boiler to generate steam from biogas produced from a co‐located dairy manure digester. The breakeven selling price of the sugar syrup from the base case, alternative scenario A, and alternative scenario B were $965, $911, and $955 per metric ton, respectively. Sensitivity analysis showed that the breakeven selling price is sensitive to the raw material cost, especially for the pectic enzymes.

Comprehensive evaluation of growth characteristics, nitrogen removal capacity, and nutritional properties of three diet microalgae

Nitrogen is one of the main pollution sources in aquaculture system. Microalgae are considered as one of the ideal bio-absorbents used in wastewater purification, due to their nitrogen removal capacity and more importantly nutritional value. Nannochloropsis oceanica, Cyclotella atomus, and Conticribra weissflogii are famous as diet microalgae. However, estimation of nitrogen removal capability and concomitant nutritional properties of the three species have been rarely reported, which was performed in this study. N. oceanica, C. atomus, and C. weissflogii were cultivated with two initial nitrate-N concentration, noted as NC (13.85 mg·L–1) and NW (5 mg·L–1) groups, respectively. All the three microalgal strains in NC group showed higher maximum cell density, specific growth rate, and biomass concentration, maximal quantum yield of PSII (Fv/Fm), total Chlorophyll and carotenoids contents than that in NW group. These results confirmed the importance of nitrogen for microalgal biomass generation and photosynthetic performance. From Fv/Fm, N. oceanica has better adaptability towards nitrogen depletion compared to other two selected strains. The three microalgae exhibited significantly stronger nitrate-N absorption efficiencies in NC group at the same timepoint, compared to NW. Analyzing the average amount of nitrate-N absorbed by each cell daily, C. weissflogii gained the largest value, followed successively by C. atomus and N. oceanica, likely due to species specificity. Moreover, three strains removed 90% of nitrate-N within five days and 99% of that within seven days, showing splendid nitrogen removal potentials. These results confirmed the feasibility of removing nitrogen from wastewater with the selected three microalgae. Nutritional properties of microalgal biomass were also investigated. For the three species, lower nitrate-N was beneficial for the production of soluble sugar, total lipid, and saturated fatty acid, while higher nitrate-N led to more soluble protein and polyunsaturated fatty acid. In summary, N. oceanica, C. atomus, and C. weissflogii all showed strong nitrogen removal capacity, whose growth characteristics and nutritional properties varied with nitrogen concentration. In practical application for assimilating nitrogen, these findings could provide some references for the selection of suitable microalgae species in order to satisfy different nutritional requirements of various aquatic animals.

Optimization of Autohydrolysis of Olive Pomaces to Obtain Bioactive Oligosaccharides: The Effect of Cultivar and Fruit Ripening

The valorisation of agro-industrial residues presents a challenge in obtaining economically sustainable and environmentally friendly industrial processes. Olive pomace is a by-product generated in large quantities, from olive oil extraction. This residue mostly consists of lignocellulosic materials. The aim of this study was to evaluate the potential use of extracted olive pomaces (EOP) obtained from olives with different ripening indexes (RI) and from different cultivars (Cobrançosa; RI = 2.5; 3.3 and 4.7; and Galega Vulgar; RI = 1.8; 2.9 and 4.8), to produce bioactive oligosaccharides from hemicelluloses by autohydrolysis. The hydrothermal treatment conditions were optimized by Response Surface Methodology, following a central composite rotatable design (CCRD), as a function of temperature (T: 142–198 °C) and time (t: 48–132 min), corresponding to severity factor (SF) values from 3.2 to 4.9. For all pomace samples, soluble sugar production was described by concave surfaces as a function of temperature and time. Autohydrolysis with SF equal or higher than 4.0 produced higher sugar yields, with maximum values around 180 g glucose equivalent/kg EOP for SF of 4.7 (190 °C/120 min) or 4.9 (198 °C/90 min). These values were similar for both cultivars and were not dependent on the ripening stage of the olives. Maximum oligosaccharide (OS) yields of 98% were obtained by autohydrolysis with SF of 4.0. The increase in SF to 4.9 resulted in a decrease in OS yield to 86–92%, due to the release of monomeric sugars. The monosaccharides were mostly xylose (55.8–67.7% in Galega; 50.4–69.0% in Cobrançosa liquid phases), and glucose, galactose, arabinose and rhamnose, in smaller quantities. Therefore, the production of bioactive xylo-oligosaccharides (XOS) from olive pomaces mainly depends on the hydrothermal conditions used.

Process development of sugar beet enzymatic hydrolysis with enzyme recycling for soluble sugar production

Enzymatic hydrolysis of sugar beets for achieving liquefaction and sugar release is a critical step for beet-ethanol production. An enzyme recycling process was developed in this study to reduce the economic uncertainty raised by the high costs of enzymes by reducing the fresh enzyme usage. A mixture of cellulases and pectinases was used in the beet hydrolysis. The hydrolysate was centrifuged and then processed through a 50 kDa molecular weight cut-off polyethersulfone membrane to recover enzymes from the liquid. Liquid enzyme recycling with 50% fresh enzyme addition achieved a similar liquefaction extent and sugar yield compared to the positive control with 100% fresh enzyme. Solid enzyme recycling showed a lower liquefaction efficiency, requiring at least 75% of fresh enzyme addition for a comparable liquefaction extent. Five sequential batches of hydrolysis with liquid enzyme recycling were successfully conducted to hydrolyze sugar beets with similar liquefaction extents and sugar yields.

Effects of periodic drought with severe exhaust exposure on particle retention capacity and physiological responses of Photinia × fraseri Dress

Urban plants are regarded as an effective agent to control particulate matter (PM) pollution by absorbing PM. Repeated PM and drought stress in urban areas often cause morphological and physiological damage to plants, resulting in lower ecological benefits. Nevertheless, knowledge in PM retention capability, morphology and physiology of plants under repeated stress and cross stress has been barely available. In order to investigate changes in these aspects under repeated stress, we applied periodic drought with severe exhaust exposure on Photinia × fraseri Dress (a common urban tree species with strong PM retention ability). The study was carried out in a six-period scenario, with a duration of 10 days for each period: initial value (R0), initial stress period (S1), initial recovery period (R1) second stress period (S2), second recovery period (R2) and final stress period (S3). The results are as follows: In terms of periodic factor, PM retention of tail gas stress group (P) and cross stress group (PD) in S2 decreased by 10.00 μg/cm2 and 12.60 μg/cm2 respectively compared with those during S1 (p > 0.05). During S3, the total amount of PM on leaf surface in both P and PD demonstrated a significant decrease (p < 0.05). The retention capacity of P. fraseri may be dramatically limited under multi-period stress. In this experiment, we attribute the decrease of PM retention to the morphological changes (shedding of mature leaves, smaller leaf area and thinner wax layer) and physiological responses (an increase in gas exchange) under multi-period stress. In terms of cross-stress factor, the total retained PM on leaf surface in PD was higher than that in P, especially during S3, and the interaction between drought and PM reached a significant level (p < 0.01, η2 = 0.808), which indicated that drought reduced the loss of dust under PM stress. Changes in morphology and gas exchange indicated that the mechanisms for the high dust retention rate on the leaf surface of PD group varied in the three stress periods. In addition, except the chlorophyll relative value, the alleviated accumulation of MDA and intense production of soluble sugar with PD showed favorable responses to disturbance compared with those in P under the repeated stress. Therefore, we infer that, under multi-period stress of drought and tail gas, P. fraseri may better maintain PM retention ability and resistance than under single stress.

Saccharomonospora actinobacterium alleviates phytotoxic hazards of tungsten nanoparticles on legumes’ growth and osmotic status

Like its bulk counterpart, tungsten (W) nanoparticles (WNPs) could induce environmental hazard to plant growth and yield, however no study investigated their phytotoxicity. On the other hand, plant growth-promoting bacteria (PGPB) can be effectively applied to reduce WNPS toxicity. Therefore, we aimed at investigating the phytotoxic effect of WPNs upon some leguminous plants and how could PGPB ameliorate this phytotoxic impact. Soil contaminated with WPNS induced the accumulation of W in all tested species, leading to marked retardation in both growth and photosynthesis as well as a noticeable oxidative damage. Five isolates of actinobacteria were isolated from Jazan, Saudi Arabia. Morphological and biochemical characterizations indicated that isolate (3) was the most bioactive one. Furthermore, PCR was performed to amplify 16S rDNA of the isolate 3 and the amplified sequence exhibited a high similarity with 16S rRNA gene from Saccharomonospora sp. Although, Saccharomonospora sp. did not affect growth of control plants, it markedly quenched the negative impact of WNPs. This was accompanied by a significant reduction in W levels in Saccharomonospora-treated plants. To cope with heavy metal stress, all tested legumes activated their osmolytes metabolism through the production of soluble sugars, proline, and polyamines, particularly in pea plants. Concomitantly, the biosynthetic key enzymes involved in sucrose, proline and spermidine polyamine biosynthesis experienced a remarkable elevation. These increases were further induced by co-application of Saccharomonospora sp. and WNPs. Overall, application of Saccharomonospora sp. under WNPs treatment induced similar metabolic responses in the three legume species, particularly pea plants, which triggered stress recovery.

When vegetation indicates reproduction: The affinity between leaf morphology and flowering commitment in the lily meristem.

At the reproductive stage, lily plants bear two morphological types of mature leaves, one at the lower and one at the upper part of the stem. At the vegetative stage, all the leaves are similar to each other and to the reproductive plant's lower leaves. This heterophylly has not yet been explored. In this study, we show that it is not a result of the plant's age but rather an outcome of floral induction. The induction appears as an on-going process, during which the meristem still produces leaves but progressively becomes committed to reproduction. This intermediate period lasts until the ultimate switch to flower primordia occurs. The leaves produced during floral induction, termed here as "inductive," appear at the upper part of the stem. Besides their typical higher stomata density, these leaves have a poly-layered palisade mesophyll, whose cells exhibit a unique morphology and contain more chlorophyll than leaves of vegetative plants. These leaves display higher carbon assimilation, soluble sugar production, and chloroplast-lipid accumulation. Accordingly, genes associated with stomata, chloroplast, and photosynthesis are upregulated in these leaves. Our results were obtained when floral induction was achieved either by vernalization or photoperiod signals, ruling out a mere environmental effect. We suggest that lily plants prepare themselves for the high-energy-demanding bloom by producing leaves with enhanced photosynthetic capacity, leading to an increase in soluble sugars. These novel findings introduce an adjacent affinity between photosynthesis and flowering and provide a nondestructive tool for identifying the plant's developmental stage-vegetative or reproductive.

Growth and physiological responses of Pennisetum sp. to cadmium stress under three different soils.

Pennisetum sp. was employed as a model species to detect the growth and physiological response to cadmium (Cd) stress at different Cd concentrations (0, 20, 50, and 100 mg kg-1) in three types of soils (yellow brown soil, yellow soil, and red soil). Results showed that the growth of Pennisetum sp. was not significantly influenced by Cd in 20 mg kg-1, but significantly inhibited at higher Cd concentrations in three types of soils. Besides, the higher Cd concentrations, the lower root, stem, and leaf biomass. With Cd concentration of soil increasing, Cd content of root, stem, and leaf increased. Compared with no Cd, high Cd concentrations (50 and 100 mg kg-1) induced the physiological indices (photosynthetic rate, stomatal conductance, transpiration rate) and biochemical indices (nitrate reductase, glutamine synthetase, and glutamate synthase activities) decreasing, but the concentration of NO3- and NH4+ increasing. The activity of antioxidative enzymes (SOD, POD, and CAT) was disrupted and the content of malondialdehyde (MDA) increasing. Pennisetum sp. could protect cells from damage and maintain normal physiological metabolism via increasing the production of soluble sugar and soluble protein, but soluble proteins and soluble sugars were limited in high concentrations of Cd (50 and 100 mg kg-1). Moreover, the growth and physiological response to Cd are different in the three types of soils. The growth of Pennisetum sp. in yellow brown soil was better than that in other two soils, and the gas exchange rate, antioxidant enzyme activity, and nitrogen metabolism in yellow soil and red soil were more affected by Cd stress than that in yellow brown soil. Overall, Pennisetum sp. had certain tolerance and biosorption ability to Cd in different Cd concentrations and different types of soil. Hence, Pennisetum sp. was a suitable choice for Cd remediation, especially in yellow brown soil.

Photoperiod modulates growth and pigments and 20-hydroxyecdysone accumulation in Brazilian ginseng [Pfaffia glomerata (Spreng.) Pedersen] grown in vitro

Photoperiod regulates different morphophysiological processes in plants, directly impacting photosynthetic performance and, consequently, primary and secondary metabolism. To date, there are no studies reporting the influence of photoperiod on the biosynthesis of phytoecdysteroids, such as 20-hydroxyecdisone (20-E). Here, we evaluated the effects of photoperiod on the development and metabolism of in vitro grown Pfaffia glomerata, an important medicinal species and producer of 20-E. Two P. glomerata accessions (Ac22 and Ac43) were cultivated for 40 days under different photoperiods: 4, 8, 16, and 24 h. Then, growth, physiological performance, 20-E content and gene expression related to the synthesis of this compound were evaluated. Longer photoperiods resulted in higher photosynthetic rates, growth, and biomass accumulation in both accessions. P. glomerata showed great plasticity to the different photoperiods tested and no sign of photoinhibition (Fv/Fm). Primary metabolism was modulated by photoperiod, with marked differences in the production of soluble sugars, starch, and amino acids. Anthocyanin production was also affected by the photoperiod. However, the accessions showed contrasting responses, in which longer photoperiods led to the highest anthocyanin contents in Ac22 and the lowest in Ac43, reflecting different adaptive strategies the light conditions. As a result of better photosynthetic performance and higher carbon availability, P. glomerata accumulated more 20-E during longer photoperiods. In this way, growing P. glomerata plants for longer photoperiods may represent a strategy for obtaining plants with larger biomass and higher 20-E yields. Photoperiod regulates the primary and secondary metabolism of P. glomerata plants grown in vitro, and longer photoperiods increase growth, photosynthetic performance, and accumulation of the phytoecdysteroid 20-hydroxyecdysone (20-E).

Pre-treatment optimization of barley straw as agro-industrial waste via alkaline peroxide and ultrasound for soluble sugar production and degradation

Pre-treatment of biomass is of great importance to maximize the recovery of fermentable sugars and minimize the amount of enzyme inhibitors formed. There are several processes that can be applied for pre-treatment of agricultural industrial waste such as chemical, physical, physico-chemical, biological, and combined pre-treatments. Alkaline hydrogen peroxide (AHP) and ultrasonication are two of this pre-treatment process. The aim of this study was to investigate the pre-treatment performance of barley straw biomass using AHP and combined ultrasonic-hydrogen peroxide process via Box-Behnken design as a response surface methodology (RSM). The factors of time (30–120 min), particle size (0.2–1 mm), peroxide dosage (1–5%), and temperature (50–100 °C) are investigated for optimum operating conditions. For ultrasonication process, factors are time (5–30 min), particle size (0.2–1.0 mm) and US power (20–100 Kj/kgDM). During AHP pre-treatment, maximum total and reduced sugar concentration was found as 14 g/L and 660 mg/L, respectively, at maximum level of time and minimum level of dosage factors which are 120 min and 1%, respectively. Maximum total and reduced sugar concentration can be reached nearly 7.6 g/L and 810 mg/L, respectively, at minimum level of time which is 5 min and almost minimum level of chemical dosage in ultrasound-hydrogen peroxide process, respectively.

Minimizing Adverse Effects of Pb on Maize Plants by Combined Treatment with Jasmonic, Salicylic Acids and Proline

Lead (Pb) is a toxic heavy metal (HM) that harms plant growth and productivity. Phytohormones, such as jasmonic acid (JA) and salicylic acid (SA), and osmoprotectants, such as proline (Pro), play an important role in the physiological and biochemical processes of plants. We investigated the effect of exogenous applications of JA, SA, Pro, and their combination on Pb-stress tolerance in maize as well as their effect on physiological, biochemical, and yield traits. Pb exposure severely affected maize plants, reducing growth, yield, photosynthetic pigments, and mineral (nitrogen, phosphorus, and potassium) nutrients, as well as enhancing electrolyte leakage (EL), malondialdehyde (MDA) accumulation, osmolytes, and non-enzymatic and enzymatic antioxidants. The application of JA, SA, Pro, and their combination enhanced plant growth and induced pigment biosynthesis, and decreased EL, MDA accumulation, and Pb concentration. All treatments enhanced Pro and total soluble sugar production, glutathione activity, ascorbic acid, phenol, superoxide dismutase, catalase, peroxidase, and mineral nutrients. JA, SA, and Pro application improved physiological processes directly or indirectly, thereby enhancing the ability of maize plants to overcome oxidative damage caused by Pb toxicity. The combination of JA, SA, and Pro was the most efficient treatment for maize plant growth and development, eliminating the negative consequences of Pb stress.

Endophytes Increased Fruit Quality with Higher Soluble Sugar Production in Honeycrisp Apple (Malus pumila).

Endophytes are fungi, bacteria, or yeast symbionts that live in the intercellular spaces or vascular tissues of host plants. Investigations indicate that endophytes isolated from the Salicaceae family (Populus and Salix) hosts provide several benefits that promote plant growth, including but not limited to di-nitrogen fixation, plant hormone production, nutrient acquisition, stress tolerance, and defense against phytopathogens. In exchange, the microorganisms receive domicile and photosynthates. Considering the known characteristics of nitrogen fixation and plant hormone production, we hypothesized that apple trees grown under nitrogen-limited conditions would show improved biometrics with endophyte inoculation. Our research objectives were to investigate the endophyte effects on plant physiology and fruiting. We examined these effects through ecophysiology metrics involving rates of photosynthesis, stomatal conductance and density, transpiration, biomass accretion, chlorophyll content and fluorescence, and fruit soluble sugar content and biomass. Our results showed evidence of the endophytes’ colonization in apple trees, decreased stomatal density, delayed leaf senescence, and increased lateral root biomass with endophytes. A highlight of the findings was a significant increase in both fruit soluble sugar content and biomass. Future research into the mechanistic underpinnings of this phenomenon stands to offer novel insights on how microbiota may alter carbohydrate metabolism under nitrogen-deficient conditions.

The Role of a Glucosinolate-Derived Nitrile in Plant Immune Responses.

Glucosinolates are defense-related secondary metabolites found in Brassicaceae. When Brassicaceae come under attack, glucosinolates are hydrolyzed into different forms of glucosinolate hydrolysis products (GHPs). Among the GHPs, isothiocyanates are the most comprehensively characterized defensive compounds, whereas the functional study of nitriles, another group of GHP, is still limited. Therefore, this study investigates whether 3-butenenitrile (3BN), a nitrile, can trigger the signaling pathways involved in the regulation of defense responses in Arabidopsis thaliana against biotic stresses. Briefly, the methodology is divided into three stages, (i) evaluate the physiological and biochemical effects of exogenous 3BN treatment on Arabidopsis, (ii) determine the metabolites involved in 3BN-mediated defense responses in Arabidopsis, and (iii) assess whether a 3BN treatment can enhance the disease tolerance of Arabidopsis against necrotrophic pathogens. As a result, a 2.5 mM 3BN treatment caused lesion formation in Arabidopsis Columbia (Col-0) plants, a process found to be modulated by nitric oxide (NO). Metabolite profiling revealed an increased production of soluble sugars, Krebs cycle associated carboxylic acids and amino acids in Arabidopsis upon a 2.5 mM 3BN treatment, presumably via NO action. Primary metabolites such as sugars and amino acids are known to be crucial components in modulating plant defense responses. Furthermore, exposure to 2.0 mM 3BN treatment began to increase the production of salicylic acid (SA) and jasmonic acid (JA) phytohormones in Arabidopsis Col-0 plants in the absence of lesion formation. The production of SA and JA in nitrate reductase loss-of function mutant (nia1nia2) plants was also induced by the 3BN treatments, with a greater induction for JA. The SA concentration in nia1nia2 plants was lower than in Col-0 plants, confirming the previously reported role of NO in controlling SA production in Arabidopsis. A 2.0 mM 3BN treatment prior to pathogen assays effectively alleviated the leaf lesion symptom of Arabidopsis Col-0 plants caused by Pectobacterium carotovorum ssp. carotovorum and Botrytis cinerea and reduced the pathogen growth on leaves. The findings of this study demonstrate that 3BN can elicit defense response pathways in Arabidopsis, which potentially involves a coordinated crosstalk between NO and phytohormone signaling.

Ammonia-salt solvent promotes cellulosic biomass deconstruction under ambient pretreatment conditions to enable rapid soluble sugar production at ultra-low enzyme loadings

Lignocellulose dissolution and fractionation into highly amorphous cellulose (and lignin) using ammonia-salt solvents under ambient conditions facilitates efficient biorefining.

Supplemental LED lighting affects the dynamics of tomato fruit growth and composition

Understanding how greenhouse crops respond to supplemental lighting with light-emitting diodes (LEDs) compared with traditional lighting systems is essential to utilize the full potential of LEDs and their further adoption in energy efficient greenhouses. This study quantified the effects of supplemental lighting with high-pressure sodium (HPS) lamps and LED light on the dynamics of fruit growth and composition in tomato (Solanum lycopersicum L.). Two tomato genotypes (‘Foundation’ and ‘Progression’) were grown under daylight supplemented either with HPS (125 μmol m−2 s−1) combined with red/blue LED lighting (106 μmol m−2 s−1, HPS + LED light treatment) or red/blue LED light only (106 + 110 μmol m−2 s−1, LED + LED light treatment); and two genotypes (‘Foundation’ and ‘NUN09204’) under daylight supplemented either with red/blue LED light (200 μmol m−2 s−1, red/blue LED light treatment) or red/blue LED + far-red LED light (200 μmol m−2 s−1 + 40 μmol m−2 s−1, red/blue + far-red LED light treatment). Fresh weight and composition in glucose, fructose, sucrose, starch, citric acid and malic acid of tomato fruits at different stages of development were measured and analyzed in terms of three main underlying components: water dilution, dilution by soluble and storage compounds and metabolism. Growing fruits under the LED + LED compared to the HPS + LED light treatments increased average fruit fresh weight in all genotypes. The red/blue + far-red LED light treatment increased the production of soluble sugar, increased the dilution by soluble and storage compounds, and reduced water dilution leading to a strong increase in glucose, fructose and sucrose concentration in the pericarp. The LED + LED light treatment did not affect the metabolism of fruit biochemical compounds compared to the HPS + LED light treatments, but caused small changes in water dilution, which were reflected in the concentration of biochemical compounds. Dilution and metabolism were involved in genotypic differences in fruit composition. Our results show that altering the spectral composition of the supplemental light in energy efficient greenhouses can be done without an effect on fruit quality or even with an improvement of tomato fruit quality. Possible physiological processes underlying these light-induced changes in fruit biochemical compounds during fruit development in different genotypes were discussed.

Plant growth retardants (PGRs) affect growth and secondary metabolite biosynthesis in Stevia rebaudiana Bertoni under drought stress

Beyond the inhibitory action against the gibberellin biosynthesis, some plant growth retardants (PGRs) can play an important role in regulating plant responses to abiotic stress through the induction of different tolerance mechanisms. The aim of the present study was the exploitation of the potential of PGRs in enhancing the resistance to drought stress in Stevia rebaudiana Bert. Therefore, the effects of three PGRs on stevia plants grown under drought stress condition were investigated. Stevia plants were first subjected to water stress and, second, treated with PGRs to detect PGRs effect on biometric, productive and phytochemical characteristics of drought stressed-plants. The control plants were uniformly irrigated at 3-day intervals, while water-stress conditions were imposed by watering the plants at 12-day intervals. Subsequently, the Chlorocholine chloride (CCC, as Copalyl diphosphate synthase inhibitor and Kaurene synthase inhibitor), Paclobutrazol (PBZ, as Kaurene oxidase inhibitor) and Daminozide (DAM, as anti-gibberellins) were applied in drought stressed-plants. The CCC and DAM were sprayed on stevia shoots, while PBZ was drenched. The obtained results showed that leaf dry weight of stevia plants was significantly reduced by drought stress, but this parameter increased as a consequence of CCC and PBZ treatments. Drought stress also caused a significant reduction in total steviol glycoside (SVglys) content. This reduction was more pronounced in drought stressed-plants treated with CCC, while PBZ was able to counteract the SVglys reduction, with SVgly content similar to that observed in the control. Similarly, PBZ was able to increase the soluble sugar production and total antioxidant capacity in the leaves of stressed-stevia plants. These findings suggested that CCC and, in particular, PBZ had a protective effect on stevia growth under drought stress by induction of antioxidant defenses and soluble sugar production. CCC seems to inhibit gibberellin biosynthesis, preventing the SVglys production, while DAM and PBZ, as gibberellin inhibitors, didn't have a negative effect on SVglys production in drought stressed-plants. This observation seems to emphasize their role in limiting the rate of target enzymes of CCC in SVglys biosynthetic pathway. Moreover, the induction of glucose production, as a substrate for SVglys biosynthesis, could be a convincing evidence for SVglys promotion in PBZ treated-plants.

Study on enzyme properties of bacillus subtilis LC-9 multifunction cellulose

Cellulose is the most abundant renewable resource in nature and can be used for the production of soluble sugars, biofuels and as raw materials for other important chemical products. Therefore, the development and research of multifunction’s enzyme is of great significance for the degradation and utilization of cellulose. In this study, two-step DEAE-Sepharose FF weak anion exchange of fermentation supernatant of Bacillus subtilis LC-9 with different pH buffer as mobile phase was used to obtain the electrophoretic ally pure protein with a molecular weight of about 32 KDa, 25 KDa. The specific activity of filter paper comprehensively characterized by enzyme was 22.68U/mg, the purification fold was 33.35 and the recovery rate was 20.52%. In this study, the purified multifunction’s enzyme not only has the activity of endoglucanase, xylanase, filter paper enzyme, exoglucanase and other cellulases, but also has the advantages of short enzyme producing time, simple purification method And other advantages, has a good prospect of industrialization.