Accumulation Of Enzymes Research Articles

Mechanisms of Microbial Plant Protection and Control of Plant Viruses.

Plant viral diseases are major constraints causing significant yield losses worldwide in agricultural and horticultural crops. The commonly used methods cannot eliminate viral load in infected plants. Many unconventional methods are presently being employed to prevent viral infection; however, every time, these methods are not found promising. As a result, it is critical to identify the most promising and sustainable management strategies for economically important plant viral diseases. The genetic makeup of 90 percent of viral diseases constitutes a single-stranded RNA; the most promising way for management of any RNA viruses is through use ribonucleases. The scope of involving beneficial microbial organisms in the integrated management of viral diseases is of the utmost importance and is highly imperative. This review highlights the importance of prokaryotic plant growth-promoting rhizobacteria/endophytic bacteria, actinomycetes, and fungal organisms, as well as their possible mechanisms for suppressing viral infection in plants via cross-protection, ISR, and the accumulation of defensive enzymes, phenolic compounds, lipopeptides, protease, and RNase activity against plant virus infection.

Structural diversity in salt excreting glands and salinity tolerance in Oryza coarctata, Sporobolus anglicus and Urochondra setulosa

Unlike the bicellular glands characteristic of all known excreting grasses, unique single-celled salt glands were discovered in the only salt tolerant species of the genus Oryza, Oryza coarctata. Salt tolerance has evolved frequently in a large number of grass lineages with distinct difference in mechanisms. Mechanisms of salt tolerance were studied in three species of grasses characterized by salt excretion: C3 wild rice species Oryza coarctata, and C4 species Sporobolus anglicus and Urochondra setulosa. The leaf anatomy and ultrastructure of salt glands, pattern of salt excretion, gas exchange, accumulation of key photosynthetic enzymes, leaf water content and osmolality, and levels of some osmolytes, were compared when grown without salt, with 200mM NaCl versus 200mM KCl. Under salt treatments, there was little effect on the capacity for CO2 assimilation, while stomatal conductance decreased with a reduction in water loss by transpiration and an increase in water use efficiency. All three species accumulate compatible solutes but with drastic differences in osmolyte composition. Having high capacity for salt excretion, they have distinct structural differences in the salt excreting machinery. S. anglicus and U. setulosa have bicellular glands while O. coarctata has unique single-celled salt glands with a partitioning membrane system that are responsible for salt excretion rather than multiple hairs as previously suggested. The features of physiological responses and salt excretion indicate similar mechanisms are involved in providing tolerance and excretion of Na+ and K+.

Toxicity assessment of metribuzin and its amelioration through plant growth regulators in Vigna radiata (L.) R. Wilczek.

The present experiment was conducted to evaluate the metribuzin-induced stress response in Vigna radiata and to explore the ameliorative role of exogenous application of plant growth regulators (PGRs) against metribuzin toxicity by assessing important biochemical and yield parameters. Prior to the field experiment, dose standardization experiments were performed, and EC50 was calculated for metribuzin. On day 21, field grown V. radiata plants were treated with graded concentrations of metribuzin (0-1000mg [Formula: see text]). Plants treated with 600mg [Formula: see text] (EC50) and 1000mg [Formula: see text] (highest dose) of metribuzin were co-treated individually and simultaneously with gibberellic acid-3 (GA), indole-3 acetic acid (IAA), and salicylic acid (SA). After 7days of treatment, leaf tissues were analyzed for biochemical parameters, whereas those related to yield were recorded during harvest. The result of this study indicated that metribuzin treatment to V. radiata resulted in increase in lipid peroxidation and reduce chlorophyll and carotenoid contents as well as yield parameters. However, metribuzin-treated plants induced proline accumulation and activity of antioxidant enzymes. Exogenous application of GA, IAA, and SA significantly reduced lipid peroxidation and increased contents of photosynthetic pigments, proline, and antioxidant enzymes thereby increasing yield parameters. It was observed that during metribuzin stress, SA exhibited a better ameliorative response out of the three exogenously applied PGRs, while the combined use of all PGRs exhibited much improved ameliorative response on biochemical and yield parameters of plants.

Trichoderma reesei as an elicitor triggers defense responses in tea plant and delays gray blight symptoms

Gray blight caused by Pestalotiopsis-like species is a major disease of tea crop worldwide including India, causes significant losses in tea production. Management of disease using fungal biocontrol agents is considered an alternative eco-friendly approach to synthetic fungicides. The present study explores the efficacy of Trichoderma reesei in the gray blight management in tea crop and activation of defense related enzymes against gray blight pathogen by developing a tri-trophic interaction system. Out of 16 isolates of Trichoderma species screened in laboratory against Pseudopestalotiopsis theae, a gray blight pathogen, isolate TRPATH01 had highest antagonistic activity (81.2%) against Ps. theae and was found to produce inhibitory volatile and non-volatile metabolites. Based on ITS and TEF-1 alpha sequencing, the isolate TRPATH01 was recognised as T. reesei. The methanolic extract of T. reesei was also found effective against Ps. theae at 200 μg/mL also confirmed presence of highest volatile compounds. The isolate also produced hydrolytic enzymes such as chitinase, cellulase, protease, and lipase. Under nursery conditions, 2% and 5% concentrations with 2 × 106 conidia/ml of T. reesei were able to reduce 67.5% to 75.0% of disease severity over pathogen inoculated controls. Moreover, compared with positive and negative controls, T. reesei -treated tea plants showed increased shoot height, stem diameter, shoot and root fresh weight at 45 days after inoculation. Principal component analysis capturing 97.1% phenotypic variations, which revealed that the tea plants co-inoculated with Ps. theae and T. reesei exhibited significantly upregulated accumulation of defensive enzymes viz., polyphenol oxidase, peroxidase, phenylalanine ammonia lyase, phenolics, β-1, 3-glucanase, and chitinase when compared to both controls. Hence, T. reesei could provide an eco-friendly and viable mitigation option for gray blight in tea gardens by inducing defense-related enzymes.

Postharvest transient water deficit limits longevity of cut Dendrobium ‘Khao Sanan’ orchid

A negative water imbalance due to a temporary water deficit (WD) after harvest can stimulate early flower senescence and reduce flower quality and vase life of orchids. To clarify the physiological responses of cut Dendrobium ‘Khao Sanan’ inflorescences under WD stress and early responses during water recovery, relative water content (RWC), water potential, reactive oxygen species (ROS), ethylene production, lipid peroxidation, antioxidant enzymes, and osmolyte were determined. The inflorescences were exposed to WD for 0, 24, 48, and 72 h after harvest, then placed in water for recovery and vase life determination. The results showed that WD significantly reduced RWC in petals, and over 24 h of WD adversely affected postharvest quality including vase life of cut inflorescences by increasing flower abscission, flower bud opening, and decreasing flower quality score. Moreover, ethylene production was induced early by 72 h of WD. Exposure of cut flowers to WD also increased hydrogen peroxide (H2O2) content, malondialdehyde (MDA) content, proline content, and lipoxygenase (LOX) activity. Additionally, ascorbate peroxidase (APX) and catalase (CAT) activities fluctuated with durations of dry and recovery periods. After rewatering, RWC, water potential, MDA content, and LOX activity of all WD periods recovered at non-WD control levels while H2O2 and proline content remained higher than control. On the other hand, ethylene production of the inflorescences exposed to WD over 24 h remarkably increased after rewatering. Our findings suggested that Dendrobium ‘Khao Sanan’ could tolerate transient WD up to 24 h with negligible reduction in longevity, probably corresponding to the lowest ethylene production during the WD period and the accumulation of antioxidant enzymes and osmolytes.

Response of plant defense enzymes against tomato early blight disease

An experiment was conducted to identify the biochemical defense enzymes, viz. catalase (CAT), peroxidase (POX), phenylalanine ammonia lyase (PAL) and total phenol responsible for resistance against A. solani in resistant (cv. H-88-78-1) and susceptible (Punjab Chhuhara) cultivars of tomato after the application of Amistar 25 SC (azoxystrobin 0.1%) during 2015 crop season. Azoxystrobin was applied for their efficacy in inducing defense enzymes in tomato against A. solani. Defense-related enzymes were increased in azoxystrobin pre-treated tomato plants. Early blight resistant tomato plants (cv. H-88-78-1) treated with novel QoI (Quinone oxidation inhibitor) fungicideazxoystrobin inoculated with A. solani under glasshouse conditions showed increased accumulation of defense enzymes, viz. CAT, POX, PAL and total phenol thancontrol plants.

Prospects for chemical and biotechnological processing of miscanthus

The processing of plant biomass into demanded and economically viable products is currently a recognized global trend. Among alternative energy directions, biomass conversion is the most predictable and sustainable carbon resource that can replace fossil fuels. Already today, plant biomass provides almost 25% of the world’s energy supply. This review provides information on the most promising areas of chemical and biotechnological processing of the biomass of such an energy plant as miscanthus. The choice of miscanthus is due to its high yield (up to 40 t/ha of sown area) and high energy yield (140–560 GJ/ha) compared to other plant materials. In addition, miscanthus is able to grow on marginal lands and does not require special agronomic measures, while in the process of its cultivation, the soil is enriched with organic substances and it is cleaned from pollutants. The review reflects the directions of processing of native biomass and pretreated biomass. Miscanthus biomass, in addition to processing into energy resources, can be fractionated and transformed into many high-value products - cellulose, cellulose nitrates, ethylene, hydroxymethylfurfural, furfural, phenols, ethylene glycol, cooking solutions after nitric acid pretreatment of miscanthus biomass can act as lignohumic fertilizers. In addition, on the basis of miscanthus cellulose hydrolysates, it is possible to obtain benign nutrient media for biotechnological transformation into bacterial nanocellulose, for the accumulation and isolation of various microbial enzymes.

Oral Administration of Therapeutic Enzyme Capsule for the Management of Inflammatory Bowel Disease.

BackgroundOral administration of proteins/peptides is challenging in clinical application due to their instability and susceptibility in the gastrointestinal tract.Materials and MethodsThe in situ polymerization on the surface of enzymes was used to encapsulate antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) in polymeric shells, and the reactive oxygen species (ROS) scavenging ability was monitored based on DCFH-DA probe using flow cytometry and confocal laser scanning microscopy. The mRNA expression level of pro-inflammatory factors was assessed by real-time qPCR, using lipopolysaccharide-induced RAW264.7 cells as a model. Finally, the enzyme capsules were orally administered for the treatment of inflammatory bowel disease using dextran sodium sulfate (DSS)-induced colitis mice as a model, based on the evaluation of the disease-associated index, ROS level and pro-inflammatory cytokines’ expression.ResultsThe enzyme capsules could effectively scavenge the intracellular reactive oxygen species (ROS) through the cascade catalysis of SOD and CAT, and thus protect the cells from ROS-induced oxidative damage. Meanwhile, the enzyme capsules could inhibit the secretion of pro-inflammatory cytokines from macrophages, thereby achieving favorable anti-inflammation effect. Oral administration of enzyme capsules could facilitate the accumulation of enzymes in the inflamed colon tissues of DSS-induced colitis mice. Moreover, the oral delivery of enzyme capsules could effectively alleviate the symptoms associated with colitis, attributing to the excellent ROS scavenging ability and the inhibition of pro-inflammatory cytokines’ level.ConclusionIn summary, our findings provided a promising approach to construct enzyme-based nano-formulations with favorable therapeutic efficacy and biocompatibility, exhibiting great potential in the treatment of gastrointestinal diseases in an oral administration manner.

Effect of Metschnikowia pulcherrima on Saccharomyces cerevisiae PDH By-Pass in MixedFermentation with Varied Sugar Concentrations of Synthetic Grape Juice and Inoculation Ratios

The effects of Metschnikowia pulcherrima and high glucose osmolality on S. cerevisiae pyruvate dehydrogenase pathway (PDH) by-pass were examined by varying the starting sugar concentration of synthetic grape juice and the inoculation ratio of S. cerevisiae to M. pulcherrima. The findings revealed that M. pulcherrima and osmolarity impacted S. cerevisiae’s PDH by-pass. The inoculation concentration of M. pulcherrima significantly affected pyruvate decarboxylase (PDC) activity and acs2 expression when the initial sugar concentration was 200 g L−1 and 290 g L−1. The osmolarity caused by the initial sugar (380 g L−1) significantly influenced the enzymatic activity of S. cerevisiae, which decreased PDC and acetaldehyde dehydrogenase (ALD) activities while increasing Acetyl-CoA synthetase (ACS) activity. The reduction in acetic acid in the wine was caused by M. pulcherrima altering the initial sugar concentration faced by S. cerevisiae, which in turn affected enzymatic activity. The alteration of enzyme activity and accumulation of primary metabolites revealed why mixed fermentation could reduce the acetic acid content in wine by altering the enzymatic activity and affecting the expression of several key genes. The M. pulcherrima inoculation levels had no significant effect on the acetic acid and glycerol concentration in the same fermentation medium.

Deciphering environmental factors and defense response of rice genotypes against sheath blight disease

Sheath blight (ShB) is one of the most serious diseases in rice, leading to severe yield losses globally. In our study, we evaluated a total of 63 rice genotypes for resistance against sheath blight disease by artificial inoculation over two seasons under field conditions and studied the weather parameters associated with disease incidence. Based on two years of testing, 23 genotypes were found moderately resistant, 38 were moderately susceptible, and 2 exhibited a susceptible reaction to sheath blight disease. Among the specific four genotypes (IC283139, IC283041, IC283038, and IC283023) of the moderately resistant group exhibited less disease reaction in comparison with check variety Tetep. Further, the correlation of percent disease index (PDI) with weather parameters revealed negative associations between PDI and maximum temperature, minimum temperature, low rainfall and the positive association with maximum relative humidity (RH) suggest that very low temperature or high precipitation might have a negative impact on pathogen establishment. In addition, the sheath blight-linked SSRs were assessed using distance and model-based approaches, results of both the models revealed that genotypes distinguished the resistant population from the susceptible one. From the output of two years of principal component analysis, two genotypes from each group of moderately resistant, moderately susceptible and susceptible were studied for their biochemical reaction against the sheath blight pathogen. The biochemical study revealed that the accumulation of defense and antioxidant enzymes, namely, polyphenol oxidase, peroxidase, total phenol, phenylalanine ammonia-lyase, catalase, and superoxide dismutase, were higher in moderately resistant genotypes, but was observed to be lower in moderately susceptible and susceptible genotypes. The statistical analysis revealed the enzyme activities (defense and antioxidant) exhibited a strong negative correlation with area under the disease progress curve (AUDPC) and influence of weather parameter RH. This demonstrates that the environment factor RH plays a major role in imparting the resistance mechanism by decreasing the enzymes activities and increasing PDI. This study found that the identified novel resistant genotype (IC283139) with purple stem base demonstrated improved resistance against sheath blight infection through a defense response and the use of antioxidant machinery.

Purification and characterization of α-amylase and protease of the phytopathogenic fungus Fusarium graminearum

One of the modern approaches in increasing the resistance of cereal crops to fungal diseases is the study of digestive enzymes of pathogens and their protein inhibitors in grain. Recently, proteases and amylases have been considered as some of the important pathogenicity factors of fungi. To obtain these enzymes, the phytopathogenic fungus F. graminearum was grown by solid state fermentation (SSF) using wheat bran. The maximum accumulation of enzymes at the addition of 2,0×106 conidia/ml occurred on day 8th of cultivation of the fungus. Extracellular protease and α-amylase with molecular weight 25 and 29 kDa, respectively, were purified by affinity chromatography.. Using specific inhibitors, the purified protease was found to belong to the serine trypsin-like enzyme. According to isoelectric focusing data, α-amylase consisted of 4 isoenzymes with strongly acidic pI of 3.0-3.5. The pH, temperature optimum, and thermostability of the enzymes were determined. The data obtained for α-amylase and trypsin of F. graminearum are presented for the first time. The results of the study can be used in the search for specific inhibitors of amylases and proteases in grain as protective proteins for their application in estimation of wheat varieties resistance to fungal attack.

Bacillus-Secreted Oxalic Acid Induces Tomato Resistance Against Gray Mold Disease Caused by Botrytis cinerea by Activating the JA/ET Pathway.

Bacillus spp. are known for their ability to control plant diseases; however, the mechanism of disease control by Bacillus spp. is still unclear. Previously, bacterial organic acids have been implicated in the process of disease suppression. We extracted the total organic acid from Bacillus cereus AR156 culture filtrate and identified oxalic acid (OA) as the programmed cell death-inducing factor. OA strongly suppressed the lesion caused by Botrytis cinerea without significant antagonism against the fungus. Low concentration of OA produced by Bacillus spp. inhibited cell death caused by high concentrations of OA in a concentration- and time-dependent manner. Pretreatment with a low concentration of OA led to higher accumulation of active oxygen-scavenging enzymes in tomato leaves and provoked the expression of defense-related genes. The activation of gene expression relied on the jasmonic acid (JA) signaling pathway but not the salicylic acid (SA) pathway. The disease suppression capacity of OA was confirmed on wild-type tomato and its SA accumulation-deficient line, while the control effect was diminished in JA synthesis-deficient mutant, suggesting that the OA-triggered resistance relied on JA and ethylene (ET) signaling transduction. OA secretion ability was widely distributed among the tested Bacillus strains and the final environmental OA concentration was under strict regulation by a pH-sensitive degradation mechanism. This study provides the first systematic analysis on the role of low-concentration OA secreted and maintained by Bacillus spp. in suppression of gray mold disease and determines the dependence of OA-mediated resistance on the JA/ET signaling pathway. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2022.

Paternal diabetes programs sex-dependent placental alterations and fetal overgrowth.

The aim of this study was to evaluate the paternal programming of sex-dependent alterations in fetoplacental growth and placental lipid metabolism regulated by peroxisome proliferator-activated receptor (PPAR) target genes in F1 diabetic males born from F0 pregestational diabetic rats. F1 control and diabetic male rats were mated with control female rats. On day 21 of gestation, F2 male and female fetoplacental growth, placental lipid levels, and protein and mRNA levels of genes involved in lipid metabolism and transport were evaluated. Fetal but not placental weight was increased in the diabetic group. Triglyceride, cholesterol and free fatty acid levels were increased in placentas of male fetuses from the diabetic group. The mRNA levels of Pparα and Pparγ coactivator 1α (Pgc-1α) were increased only in placentas of male fetuses from the diabetic group. Protein levels of PPARα and PGC-1α were decreased only in placentas of male fetuses from the diabetic group. No differences were found in Pparγ mRNA and protein levels in placentas from the diabetic group. The mRNA levels of genes involved in lipid synthesis showed no differences between groups, whereas the mRNA levels of genes involved in lipid oxidation and transport were increased only in placentas of male fetuses from the diabetic group. In conclusion, paternal diabetes programs fetal overgrowth and sex-dependent effects on the regulation of lipid metabolism in the placenta, where only placentas of male fetuses show an increase in lipid accumulation and mRNA expression of enzymes involved in lipid oxidation and transport pathways.

The regulatory role of the Aspergillus flavus core retromer complex in aflatoxin metabolism

Aflatoxins are a series of highly toxic and carcinogenic secondary metabolites that are synthesized by Aspergillus species. The degradation of aflatoxin enzymes is an important regulatory mechanism which modulates mycotoxin producing. The retromer complex is responsible for the retrograde transport of specific biomolecules and the vacuolar fusion in the intracellular transport. Late endosomal-associated GTPase (Rab7) has been shown to be a downstream effector protein of the retromer complex. A deficiency in the retromer complex or Rab7 results in several cellular trafficking problems in yeast and humans, like protein abnormal accumulation. However, whether retromer dysfunction is involved in aflatoxin synthesis remains unclear. Here, we report that the core retromer complex, which comprises three vacuolar protein sorting-associated proteins (AflVps26-AflVps29-AflVps35), is essential for the development of dormant and resistant fungal forms such as conidia (asexual reproductive spore) and sclerotia (hardened fungal mycelium), as well as aflatoxin production and pathogenicity, in Aspergillus flavus. In particular, we show the AflVps26-AflVps29-AflVps35 complex is negatively correlated with aflatoxin exportation. Structural simulation, site-specific mutagenesis, and coimmunoprecipitation experiments showed that interactions among AflVps26, AflVps29, and AflVps35 played crucial roles in the retromer complex executing its core functions. We further found an intrinsic connection between AflRab7 and the retromer involved in vesicle-vacuole fusion, which in turn affected the accumulation of aflatoxin synthesis-associated enzymes, suggesting that they work together to regulate the production of toxins. Overall, these results provide mechanistic insights that contribute to our understanding of the regulatory role of the core retromer complex in aflatoxin metabolism.

Impact of Modified Atmospheres on Growth and Metabolism of Meat-Spoilage Relevant Photobacterium spp. as Predicted by Comparative Proteomics.

Modified atmosphere packaging (MAP) is a common strategy to selectively prevent the growth of certain species of meat spoiling bacteria. This study aimed to determine the impact of high oxygen MAP (70% O2, 30% CO2, red and white meats) and oxygen-free MAP (70% N2, 30% CO2, also white meat and seafood) on preventing the growth of spoiling photobacteria on meat. Growth of Photobacterium carnosum and P. phosphoreum was monitored in a meat simulation media under different gas mixtures of nitrogen, oxygen, and carbon dioxide, and samples were taken during exponential growth for a comparative proteomic analysis. Growth under air atmosphere appears optimal, particularly for P. carnosum. Enhanced protein accumulation affected energy metabolism, respiration, oxygen consuming reactions, and lipid usage. However, all the other atmospheres show some degree of growth reduction. An increase in oxygen concentration leads to an increase in enzymes counteracting oxidative stress for both species and enhancement of heme utilization and iron-sulfur cluster assembly proteins for P. phosphoreum. Absence of oxygen appears to switch the metabolism toward fermentative pathways where either ribose (P. phosphoreum) or glycogen (P. carnosum) appear to be the preferred substrates. Additionally, it promotes the use of alternative electron donors/acceptors, mainly formate and nitrate/nitrite. Stress response is manifested as an enhanced accumulation of enzymes that is able to produce ammonia (e.g., carbonic anhydrase, hydroxylamine reductase) and regulate osmotic stress. Our results suggest that photobacteria do not sense the environmental levels of carbon dioxide, but rather adapt to their own anaerobic metabolism. The regulation in presence of carbon dioxide is limited and strain-specific under anaerobic conditions. However, when oxygen at air-like concentration (21%) is present together with carbon dioxide (30%), the oxidative stress appears enhanced compared to air conditions (very low carbon dioxide), as explained if both gases have a synergistic effect. This is further supported by the increase in oxygen concentration in the presence of carbon dioxide. The atmosphere is able to fully inhibit P. carnosum, heavily reduce P. phosphoreum growth in vitro, and trigger diversification of energy production with higher energetic cost, highlighting the importance of concomitant bacteria for their growth on raw meat under said atmosphere.

Nitrogen modified atmosphere packaging maintains the bioactive compounds and antioxidant capacity of postharvest fresh edible peanuts

In the present study, fresh edible peanuts were packaged with nitrogen and oxygen (N2: O2 = 9:1) (modified atmosphere packaging, MAP) or air (control) and stored at 4 °C for 120 d. The physio-chemical properties, enzyme activities, and antioxidant capacity of fresh peanut kernels were analyzed at different time points during storage to investigate the effect of MAP on the preservation of this product. In comparison with control, the MAP treatment could efficaciously maintain the commodity characteristics of fresh edible peanuts by inhibiting the browning, increasing the firmness, and decelerating the accumulation of malondialdehyde and hydrogen peroxidase, the production of superoxide anion, and the electrolyte leakage rate of fresh edible peanut kernels. In addition, MAP-treated peanut kernels exhibited higher activities of the enzymes in the phenylpropanoid pathway, including phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, and 4-coumarate-CoA ligase, and higher total phenolics, flavonoids and resveratrol contents. Activities of the antioxidant enzymes superoxide dismutase (SOD), peroxidase, and catalase, and antioxidant capacity [as measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant potential (FRAP)] were also maintained in the MAP-treated kernels. Furthermore, positive Pearson’s correlations were observed between FRAP and total phenolics (r2 = 0.93), total flavonoids (r2 = 0.91), and SOD (r2 = 0.95), as well as between DPPH and SOD (r2 = 0.89) and total flavonoids (r2 = 0.77). Our results therefore suggest that MAP is a promising strategy to enhance bioactive compounds accumulation and activities of antioxidant enzymes in fresh edible peanuts during postharvest storage, hence providing valuable insights into preserving this important protein source.

Investigations into Multiple Acyl‐CoA Assimilation Pathways in a Single Organism

By 2050 there could be around 12 billion tons of plastic in landfills and the natural environment, which could be avoided by using a more environmentally friendly alternative: biologically produced plastic, or bioplastic. Polyhydroxybutyrate (PHB) is a bioplastic whose precursor is an intermediate in the ethylmalonyl‐CoA pathway (EMCP), a pathway for acetyl‐CoA assimilation in bacteria. The genes that encode the enzymes for two different acetyl‐CoA assimilation pathways, the glyoxylate bypass (GB) and the EMCP, have been observed in two PHB‐producing bacteria: Rhodobacter capsulatus and Paracoccus denitrificans. It was previously observed that P. denitrificans asynchronously uses both pathways when grown with acetate. We produced R. capsulatus fusion strains by fusing the gene for a fluorescent protein, mCherry, to the gene of a key enzyme of the EMCP or GB and observed the fluorescence during growth with acetate. Tracking fluorescence allowed us to track the accumulation of each key enzyme, which indirectly indicates the activity of the pathway. We observed that unlike P. denitrificans, the GB in R. capsulatus is not essential to growth with acetate. Understanding the use/occurrence of the EMCP in bacteria is a step to being able to manipulate the EMCP to produce commercially relevant levels of bioplastic and related products.

TaNBR1, a Novel Wheat NBR1-like Domain Gene Negatively Regulates Drought Stress Tolerance in Transgenic Arabidopsis.

Drought stress is an important factor that severely affects crop yield and quality. Autophagy has a crucial role in the responses to abiotic stresses. In this study, we explore TaNBR1 in response to drought stress. Expression of the TaNBR1 gene was strongly induced by NaCl, PEG, and abscisic acid treatments. The TaNBR1 protein is localized in the Golgi apparatus and autophagosome. Transgenic Arabidopsis plants overexpressing TaNBR1 exhibited reduced drought tolerance. When subjected to drought stress, compared to the wild-type (WT) lines, the transgenic overexpressing TaNBR1 plants had a lower seed germination rate, relative water content, proline content, and reduced accumulation of antioxidant enzymes, i.e., superoxide dismutase, peroxidase, and catalase, as well as higher chlorophyll losses, malondialdehyde contents, and water loss. The transgenic plants overexpressing TaNBR1 produced much shorter roots in response to mannitol stress, in comparison to the WT plants, and they exhibited greater sensitivity to abscisic acid treatment. The expression levels of the genes related to stress in the transgenic plants were affected in response to drought stress. Our results indicate that TaNBR1 negatively regulates drought stress responses by affecting the expression of stress-related genes in Arabidopsis.

Wheat variety carrying 2NvS chromosomal segment provides yield advantage through lowering terminal heat-induced oxidative stress.

A 2NvS chromosomal segment carrying bread wheat variety, BARI Gom 33 ('BG33'), showed tolerance to terminal heat stress andhigher yield over a heat-tolerant non-2NvS BARI Gom 26 ('BG26') and a heat-susceptible Pavon 76 ('Pavon'). This study aimed to ascertain the potential of the 2NvS 'BG33' in terminal heat-induced oxidative stress tolerance compared to non-2NvS 'BG26' and heat-susceptible 'Pavon' under two heat regimes at the reproductive stages viz. control (optimum sowing time) and heat stress (late sowing). We found that both 'BG26' and 'BG33' showed significantly higher tolerance to oxidative stress by limiting the generation of reactive oxygen species (ROS), methylglyoxal under heat stress. During terminal heat stress, both 'BG33' and 'BG26' exhibited greater cellular homeostasis than heat-susceptible 'Pavon', which was maintained by the increased accumulation of osmolytes, nonenzymatic antioxidants, and enzymes associated with ROS scavenging, ascorbate-glutathione cycle, and glyoxalase system. Lesser cellular damage in 'BG26' and 'BG33' was eventually imitated in a smaller reduction in grain yield (15 and 12%, respectively) than in 'Pavon', which had a 33% reduction owing to heat stress. Collectively, our findings revealed that the chromosomal segment 2NvS provides yield advantage to 'BG33' under terminal heat stress by lowering oxidative damage. As 2NvS translocation contains multiple nucleotide-binding domain leucine-rich repeat containing, cytochrome P450, and other gene families associated with plant stress tolerance, further studies are warranted to dissect the underlying molecular mechanisms associated with higher heat stress tolerance of 2NvS carrying 'BG33'.

Salt stress induces Kranz anatomy and expression of C4 photosynthetic enzymes in the amphibious sedge Eleocharis vivipara

Eleocharis vivipara Link is a unique amphibious leafless plant of the Cyperaceae. The terrestrial form develops culms with Kranz anatomy and C4-like traits, while the submerged form does culms with non-Kranz anatomy and C3 traits. The submerged form develops new culms with C4-like mode when exposed to air or exogenous abscisic acid. In this study, we investigated whether salt stress (0.05-0.3M NaCl) has a similar effect. When the submerged form was grown for one month in solutions of 0.1M NaCl and more, culm growth was strongly suppressed. However, these plants slowly developed new culms that had Kranz anatomy with chloroplast-abundant Kranz bundle sheath cells. Although the culms of the submerged form had only few stomata, culms grown in the NaCl solution had many stomata. The NaCl-grown culms also accumulated large amounts of C4 photosynthetic enzymes (phosphoenolpyruvate carboxylase and pyruvate Pi dikinase), and the cellular localization patterns of these enzymes and ribulose 1,5-bisphosphate carboxylase/oxygenase were similar to those in terrestrial culms. Accumulation of C4 enzymes increased in mature culms of the submerged form (with non-Kranz anatomy) when exposed to 0.2M NaCl solution for one week. These results suggest that salt stress induces development of Kranz anatomy and expression of C4 photosynthetic enzymes in the submerged C3 form of E. vivipara, whereas the anatomical and biochemical traits of C4 photosynthesis appear to be regulated independently.