Synthase Gene Expression Research Articles

Genome-wide transcriptome analysis and characterization of the cytochrome P450 flavonoid biosynthesis genes in pigeon pea (Cajanus cajan).

226 CcCYP450 genes were identified at the genomic level and were classified into 45 clades based on phylogenetic analysis. CcCYP75B165 gene was found that might play important roles in the biosynthesis of flavonoids in pigeon pea, and was significantly induced by methyl jasmonate (MeJA). The cytochrome P450 mono-oxygenase (CYP450) superfamily plays a key role in the flavonoid biosynthesis pathway and resists different kinds of stresses. Several CYP450 genes have been identified to be involved in the biosynthesis of crop protection agents. However, the CcCYP450 genes from pigeon pea have not been identified. Here, 226 CcCYP450 genes were identified at the genomic level by analysing the gene structure, distribution on chromosomes, gene duplication, and conserved motifs and were classified into 45 clades based on phylogenetic analysis. RNA-seq analysis revealed clear details of CcCYP450 genes that varied with time of MeJA (methyl jasmonate) induction. Among them, six CcCYP450 subfamily genes were found that might play important roles in the biosynthesis of flavonoids in pigeon pea. The overexpression of CcCYP75B165 in pigeon pea significantly induced the accumulation of genistin and downregulated the contents of cajaninstilbene acid, apigenin, isovitexin, and genistein and the expression of flavonoid synthase genes. This study provides theoretical guidance and plant genetic resources for cultivating new pigeon pea varieties with high flavonoid contents and exploring the molecular mechanisms of the biosynthesis of flavonoids under MeJA treatment.

Juvenile Hormone Is an Important Factor in Regulating Aspongopus chinensis Dallas Diapause.

Aspongopus chinensis is a Chinese traditional edible and medicinal insect, which is in great demand in the society. This insect reproduces once a year which is caused by reproductive diapause resulting in insufficient production in wild resources. However, the mechanism of diapause in A. chinensis is still unclear. In this study, we focus on the relationship between juvenile hormones (JHs) and A. chinensis diapause. The results showed that JHIII concentration in diapause adult individuals was significantly lower than that in diapause termination adult individuals. When exogenous JHⅢ was injected into diapause adults, the rate of mating was increased significantly, development of the reproductive systems was accelerated, consumption of fat intensified, the expression of juvenile hormone acid o-methyl-transferase (JHAMT) was upregulated, and juvenile hormone epoxide hydrolase (JHEH) and fatty acid synthase (FAS) gene expressions were downregulated. In addition, RNAi of JHAMT decreased JH concentration, delayed the development of reproductive systems, slowed down fat consumption, and delayed the mean mating occurrence time significantly. Conversely, RNAi of JHEH resulted in an increased concentration of JH, development of reproductive systems was accelerated, consumption of fat was intensified, and mean mating occurrence time advanced significantly. Taken together, these findings uncovered that JH plays an important role in regulating reproductive diapause in A. chinensis and, thus, could provide a theoretical basis for further research on the diapause of A. chinensis.

Trace elements study using x-ray fluorescence, charantin accumulation and squalene synthase gene expression in different Momordica charantia Linn fruit

Trace elements study using x-ray fluorescence, charantin accumulation and squalene synthase gene expression in different Momordica charantia Linn fruit

The jasmonate-induced bHLH gene SlJIG functions in terpene biosynthesis and resistance to insects and fungus.

Jasmonic acid (JA) is a key regulator of plant defense responses. Although the transcription factor MYC2, the master regulator of the JA signaling pathway, orchestrates a hierarchical transcriptional cascade that regulates the JA responses, only a few transcriptional regulators involved in this cascade have been described. Here, we identified the basic helix-loop-helix (bHLH) transcription factor gene in tomato (Solanum lycopersicum), METHYL JASMONATE (MeJA)-INDUCED GENE (SlJIG), the expression of which was strongly induced by MeJA treatment. Genetic and molecular biology experiments revealed that SlJIG is a direct target of MYC2. SlJIG knockout plants generated by gene editing had lower terpene contents than the wild type from the lower expression of TERPENE SYNTHASE (TPS) genes, rendering them more appealing to cotton bollworm (Helicoverpa armigera). Moreover, SlJIG knockouts exhibited weaker JA-mediated induction of TPSs, suggesting that SlJIG may participate in JA-induced terpene biosynthesis. Knocking out SlJIG also resulted in attenuated expression of JA-responsive defense genes, which may contribute to the observed lower resistance to cotton bollworm and to the fungus Botrytis cinerea. We conclude that SlJIG is a direct target of MYC2, forms a MYC2-SlJIG module, and functions in terpene biosynthesis and resistance against cotton bollworm and B. cinerea.

POU-M2 promotes juvenile hormone biosynthesis by directly activating the transcription of juvenile hormone synthetic enzyme genes in Bombyx mori.

Juvenile hormone (JH) plays a key role in preventing larval precocious metamorphosis, maintaining larval state, controlling adult sexual development and promoting insect egg maturation. Genetic studies have shown that POU factor ventral veins lacking regulates JH synthesis to control the timing of insect metamorphosis. However, how POU factor regulates JH synthesis is largely unknown. Here, we found POU-M2 was highly expressed in corpora allata (CA) and specifically localized in the nucleus of CA. The overexpression of POU-M2 promoted the expression of JH synthase genes and kr-h1 and enhanced the activity of JH synthase genes promoter. Further, POU-M2 promoted the transcription of JH acid O-methyltransferase (JHAMT) by directly binding to the key cis-regulatory elements -207, -249 and -453 within the proximal regions of JHAMT promoter. Both the POU domain and homeodomain were vital for the activation of POU-M2 on JHAMT transcription. Our study reveals the mechanism by which POU-M2 regulates JHAMT transcription.

Branched-chain amino acid supplementation impairs insulin sensitivity and promotes lipogenesis during exercise in diet-induced obese mice.

Branched-chain amino acids (BCAAs) are popular dietary supplements for exercise. However, increased BCAA levels positively correlate with obesity and diabetes. The metabolic impact of BCAA supplementation on insulin sensitivity during exercise is less understood. Male C57BL/6 mice were fed for 12 weeks with a high-fat diet, normal chow diet, or BCAA-restricted high-fat diet. They were subjected to running exercise with or without BCAA treatment for another 12 weeks. Exercise reduced body weight, improved insulin sensitivity, lowered BCAAs in plasma, and inhibited the upregulation of BCAAs and metabolites caused by BCAA supplementation in the subcutaneous white adipose tissue (sWAT) of obese mice. BCAA supplementation reversed insulin sensitivity ameliorated by exercise. The phosphorylation of protein kinase B (Ser473 and Ser474) was decreased by BCAAs in the sWAT of obese mice. However, BCAA supplementation had no such effects in lean mice. BCAAs also increased the expression of fatty acid synthase and other lipogenesis genes in the sWAT of exercised obese mice. BCAA restriction had no effect on body weight and insulin sensitivity in obese mice. BCAA supplementation impaired the beneficial effect of exercise on glycolipid metabolism in obese but not lean mice. Caution should be taken regarding the use of BCAAs for individuals with obesity who exercise.

Gold Nanoparticles Green-Synthesized by the Suaeda japonica Leaf Extract and Screening of Anti-Inflammatory Activities on RAW 267.4 Macrophages

Biosynthesis of gold nanoparticles from medicinal plants has become a modern strategy in biomedical research based on their exclusive properties, including specific targeting, lower toxicity, and biocompatibility. In this study, gold nanoparticles, reduced by the Suaeda japonica leaf extract, were promptly validated by UV–visible (UV–Vis) spectroscopy at 548 nm. No additional reducing agents were needed in this kind of a reduction reaction, which provided evidence of green synthesis. Dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), field-emission transmission electron microscopy (FE-TEM), selected area electron diffraction (SAED), and X-ray diffraction (XRD) analyses were used to illustrate the nanoscale characterization of S. japonica gold nanoparticles (Sj-AuNps). Furthermore, the cytotoxicity effect of Sj-AuNps against the RAW 264.7 cell line was determined by performing an MTT assay. We also investigated Sj-AuNps’ anti-inflammatory properties in LPS-induced murine macrophages. These nanoparticles reduced the generation of nitric oxide (NO) and prostaglandin E2 (PGE2) and repressed the expression of the LPS-stimulated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) genes. This study presents a significant biomedical application of S. japonica AuNps. The anti-inflammatory capabilities of Sj-AuNps underline their potential as possible options for suppressing inflammation-mediated diseases.

Dietary protein/carbohydrate ratio and feeding frequency affect feed utilization, intermediary metabolism, and economic efficiency of gilthead seabream (Sparus aurata) juveniles

To evaluate the effects of dietary protein/carbohydrate (P/CHO) ratio and feeding frequency (FF) on growth, intermediary metabolism, and economic efficiency of gilthead seabream (Sparus aurata) juveniles, two practical isolipidic (17%) diets were formulated to include high protein (50%)/ low starch (10%) (diet P50/CHO10) or low protein (40%)/ high starch (20%) (diet P40/CHO20). Triplicate groups of fish with 9.1 ± 0.01 g were fed for 60 days with these diets until visual satiation at three FF: one (9:00), two (9:00 and 17:00), or three (9:00, 13:00, and 17:00) meals per day. Dietary P/CHO ratios did not affect growth performance while feeding 2 or 3 meals per day improved fish growth. Fish fed diet P40/CHO20 had increased feed intake (FI), protein efficiency ratio (PER), and nitrogen retention (NR), and lower feed efficiency (FE), nitrogen intake (NI), and economic conversion ratio (ECR). Feeding 2 or 3 meals per day increased FI, NI, ECR, and economic profit index, and decreased FE, PER, and NR. Fish fed diet P40/CHO20 presented increased hepatic lipid and glycogen content, hepatocyte area covered by lipid vacuoles, and glucokinase (gk) gene expression, and decreased glutamate dehydrogenase expression. Fish fed 3 meals per day had decreased plasma triglycerides and total protein levels, while fish fed 2 or 3 meals per day presented decreased hepatic growth hormone receptor-i (ghr-i), gk, and fatty acid synthase gene expression. Interaction between P/CHO ratio and FF was only observed in plasmatic glucose, cholesterol, and total lipids levels, and insulin-like growth factor-1, and ghr-ii gene expression. Overall, glycogenesis, glycolysis, and economic efficiency seemed to be increased while the amino acid catabolism was reduced in fish fed the P40/CHO20 diet. Higher FF increased growth and economic efficiency, and reduced glycolysis and lipogenesis pathways. In conclusion, a diet with P40/CHO20 ratio fed twice a day appears to be the most adequate strategy regarding feed utilization and economic efficiency for gilthead seabream juveniles in order to achieve optimum sustainable aquaculture.

The Outer Membrane Vesicles of Salmonella enterica Serovar Typhimurium Activate Chicken Immune Cells through Lipopolysaccharides and Membrane Proteins.

Salmonella is a common pathogen which can secrete outer membrane vesicles (OMVs). However, the effect of OMVs from Salmonella enterica Serovar Typhimurium (S. Typhimurium) of poultry origin on cells of the chicken innate immune system is not well known. In this study, S. Typhimurium OMVs were first isolated from three different poultry strains of Salmonella, Salmonella CVCC542, SALA, and SALB. In order to investigate the effect of OMVs on the maturation of monocytes into macrophages, both bone marrow-derived (BMD) monocytes and macrophage cell line HD11 cells were used. OMVs promoted the formation of monocyte dendrites in both types of cells, enabled BMD cells to become larger, and stimulated expression of LPS-induced TNF-αfactor (LITAF), IL-6, and inducible nitric oxide synthase (iNOS) genes in HD11 cells. These results demonstrated the capability of OMVs to promote the development of chicken monocytes into macrophages and the maturation of macrophages. In order to study the effect of OMVs on the phagocytosis of macrophages, chicken spleen-derived monocytes and HD11 cells were used. Phagocytosis of FITC-Salmonella and FITC-dextran by these two types of cells was enhanced after stimulation with OMVs. To determine which components in OMVs were responsible for the above observed results, OMVs were treated with proteinase K(PK) or polymyxin B (PMB). Both treatments reduced the phagocytosis of FITC-Salmonella by HD11 cells and chicken spleen mononuclear cells and reduced the secretion of IL-1β, LITAF, and IL-6 cytokines. These results demonstrated that Salmonella OMVs activated chicken macrophages and spleen mononuclear cells and the activation was achieved mainly through lipopolysaccharides and membrane proteins.

Chronic rapamycin pretreatment modulates arginase/inducible nitric oxide synthase balance attenuating aging-dependent susceptibility to Trypanosoma cruzi infection and acute myocarditis.

Considering the efficacy of rapamycin in increasing lifespan and healthspan, attenuating the aging-dependent immunological decline, we compared the evolution of Trypanosoma cruzi infection and acute myocarditis in young and elderly mice untreated and chronically treated with this drug. Five groups were investigated: young uninfected and infected, elderly uninfected and infected with Trypanosoma cruzi untreated and treated with rapamycin (4mg/kg every 3days) from the 8th to the 96th week of age. Seven days after the last treatment, elderly mice were inoculated with T. cruzi. Young animals were infected at 8-weeks-old. Untreated elderly mice exhibited increase parasitemia, parasite load and myocarditis, which were associated to down-regulation in IL-2, IL-6, IFN-γ, TNF, anti-T. cruzi immunoglobulin G (IgG) total, IgG1 and IgG2a plasma levels, inducible nitric oxide synthase (iNOS) gene expression and nitric oxide (NO) cardiac production, as well as upregulation in Arginase-1 gene expression and arginase activity compared to young animals. These parameters were improved in rapamycin-pretreated elderly mice, which exhibited a better parasitological control, reduced heart inflammation and microstructural damage. These responses were associated with a better balance between Th1 and Th2 effectors similar to that observed in young animals, including an improved activation of Th1 cytokines and the iNOS pathway that positively regulates NO biosynthesis, contradicting the predominant activation of the arginase pathway in untreated elderly animals. Thus, our findings suggest that chronic pretreatment with rapamycin can attenuate immunosenescence in mice, contributing to prolong parasite resistance and attenuate acute myocarditis in elderly host challenged by T. cruzi.

Dot Blot Assay for Assessing Trehalose-6-phosphate Synthase Gene Expression in a Maize Breeding Population under Water Stress

Field maize is an important economic crop grown around the world and it has been mainly used in the animal feed industry. Maize yields have been inadequate for the demand due to drought events. One way to alleviate yield losses is to develop drought tolerant maize varieties for farmers. Trehalose-6-phosphate synthase (TPS) is an important enzyme involved in trehalose biosynthesis which has been found to increase plant tolerance to abiotic stresses. The aim of this research was to screen the levels of TPS gene expression in maize breeding materials under water stress via dot-blot hybridization using cDNA probe. To do so, 34 S2 maize families were grown and subjected to water stress condition. Leave samples were collected at 6 different days after planting (DAP) for a dot blot assay. The results showed that the level of TPS gene expression was highest at 4 days after stress (relative intensity at 64 DAP). However, dot blotting at 6 days after stress (relative intensity at 66 DAP) was effective to differentiate maize families. Furthermore, a moderate negative relationship between relative signal intensity at 66 DAP (RI66) and Smith index based on multi-phenotypic traits was found to be statistically significant. Our study showed that maize with high TPS gene expression tended to be less tolerant to water stress. It is noteworthy that the study of TPS gene expression in mature maize under stress in this study showed results that contrasted with previous reports on seedlings in many plant species. Furthermore, we found that 4 out of 34 S2 maize families may have potential for further use in our breeding program.

Antinociceptive effect of N-acetyl glucosamine in a rat model of neuropathic pain.

This study was aimed at evaluating the efficacy of glucosamine and potential mechanisms of actions in a neuropathic pain model in rats. Glucosamine (500, 1000 and 2000 mg/kg) was administered via gavage route, 1 day before the chronic constriction injury (CCI) of sciatic nerve and daily for 14 days (prophylactic regimen), or from days 5 to 14 post-injury (therapeutic regimen), as the indicators of neuropathic pain, mechanical allodynia, cold allodynia and thermal hyperalgesia were assessed on days 0, 3, 5, 7, 10 and 14 after ligation. Inducible nitric oxide synthase (iNOS) and tumour necrosis factor alpha (TNF-α) gene expressions were measured by real-time polymerase chain reaction. TNF-α protein content was measured using the enzyme-linked immunosorbent assay method. Three days after nerve injury, the threshold of pain was declined among animals subjected to neuropathic pain. Mechanical and cold allodynia, as well as thermal hyperalgesia were attenuated by glucosamine (500, 1000, 2000 mg/kg) in the prophylactic regimen. However, existing pain was not decreased by this drug. Increased mRNA expression of iNOS and TNF-α was significantly reduced in the spinal cord of CCI animals by glucosamine (500, 1000, 2000 mg/kg) in the prophylactic regimen. The overall expression of spinal TNF-α was increased by CCI, but this increase was reduced in animals receiving glucosamine prophylactic treatment. Findings suggest that glucosamine as a safe supplement may be a useful candidate in preventing neuropathic pain following nerve injury. Antioxidant and anti-inflammatory effects may be at least in part responsible for the antinociceptive effects of this drug.

Biosynthetic Potential of the Endophytic Fungus Helotiales sp. BL73 Revealed via Compound Identification and Genome Mining.

Endophytic fungi have been recognized as prolific producers of chemically diverse secondary metabolites. In this work, we describe a new representative of the order Helotiales isolated from the medicinal plant Bergenia pacumbis. Several bioactive secondary metabolites were produced by this Helotiales sp. BL 73 isolate grown on rice medium, including cochlioquinones and isofusidienols. Sequencing and analysis of the approximately 59-Mb genome revealed at least 77 secondary metabolite biosynthesis gene clusters, of which several could be associated with detected compounds or linked to previously reported molecules. Four terpene synthase genes identified in the BL73 genome were codon optimized and expressed, together with farnesyl-, geranyl-, and geranylgeranyl-pyrophosphate synthases, in Streptomyces spp. An analysis of recombinant strains revealed the production of linalool and its oxidized form, terpenoids typically associated with plants, as well as a yet unidentified terpenoid. This study demonstrates the importance of a complex approach to the investigation of the biosynthetic potential of endophytic fungi using both conventional methods and genome mining. IMPORTANCE Endophytic fungi represent an as yet underexplored source of secondary metabolites, of which some may have industrial and medical applications. We isolated a slow-growing fungus belonging to the order Helotiales from the traditional medicinal plant Bergenia pacumbis and characterized its potential to biosynthesize secondary metabolites. We used cultivation of the isolate with a subsequent analysis of compounds produced, bioinformatics-based mining of the genome, and heterologous expression of several terpene synthase genes. Our study revealed that this Helotiales isolate has enormous potential to produce structurally diverse natural products, including polyketides, nonribosomally synthesized peptides, terpenoids, and ribosomally synthesized and posttranslationally modified peptides (RiPPs). Identification of meroterpenoids and xanthones, along with establishing a link between these molecules and their putative biosynthetic genes, sets the stage for investigation of the respective biosynthetic pathways. The heterologous production of terpenoids suggests that this approach can be used for the discovery of new compounds belonging to this chemical class using Streptomyces bacteria as hosts.

Potential differences in chitin synthesis ability cause different sensitivities to diflubenzuron among three strains of Daphnia magna.

Ecotoxicity testing of crustaceans using Daphnia magna has been implemented in the chemical management systems of various countries. While the chemical sensitivity of D. magna varies depending on genetically different clonal lineages, the strain used in ecotoxicity tests, including the acute immobilization test (OECD TG202), has not been specified. We hypothesized that comprehensive gene expression profiles could provide useful information on phenotypic differences among strains, including chemical sensitivity. To test this hypothesis, we performed mRNA sequencing on three different strains (NIES, England, and Clone 5) of D. magna under culture conditions. The resulting expression profile of the NIES strain was clearly different compared to the profiles of the other two strains. Gene ontology (GO) enrichment analysis suggested that chitin metabolism was significantly enriched in the NIES strain compared to that in the England strain. Consistent with the GO analysis, evidence of high levels of chitin metabolism in the NIES strain were observed across multiple levels of biological organization, such as expression of chitin synthase genes, chitin content, and chitinase activity, which suggested that the different strains would exhibit different sensitivities to chemicals used to inhibit chitin synthesis. We found that among all strains, the NIES strain was more tolerant to diflubenzuron, a chitin synthesis inhibitor, with a 14-fold difference in the 48h-EC50 value for the acute immobilization test compared to the England strain. The present study demonstrates that the differences among strains in chitin metabolism may lead to sensitivity difference to diflubenzuron, and serves as a case study of the usefulness of comprehensive gene expression profiles in finding sensitivity differences.

Preventive effects of sea cucumber (Apostichopus japonicus) ethanol extract on palmitate-induced vascular injury in vivo

Cardiovascular diseases (CVDs) have posed serious public health problems, accounting for nearly 30% of mortality worldwide and their incidence is still increasing. Therefore, new treatment resources are necessary to prevent or manage the ever-increasing population of patients with CVDs. Sea cucumber is well known for its medical and health benefit effects, but it is not well known what/how effect it has on vascular disease. In the present study, we examined the protect effect of sea cucumber, Apostichopus japonicus 80% ethanol extract (AJE) on zebrafish embryo with the stimulation of free fatty acid, palmitate (PA). In vivo study showed that AJE can attenuate PA-induced toxicity through relieving the rapid heartbeat, increasing the survival rate and reducing the malformation in both wild type and Tg (flila:eGFP) transgenic zebrafish lines. Additionally, compare with PA treated embryos, the yolk sac area, body length, axial vascular segment (AVS) and intersegmental vessel (ISV) of the co-treatment group of AJE and PA were comparable to the control group. Moreover, AJE lowered the expression of inducible nitric oxide synthase (iNOS), nitric oxide (NO) and inflammation-related genes induced by PA, and inhibited PA-induced vascular development disorders. Our data preliminarily verify that AJE could be a candidate resource for the prevention or therapy of CVDs.

Interplay of Oxidative Stress and Nitric Oxide Synthase Gene Expression on Cardiovascular Responses in Preeclampsia.

To assess the influence of oxidative stress on the gene expression of nitric oxide synthases (NOS 3 and NOS 2) and, hence, the cardiovascular responses in preeclampsia. This was a case control study in which patients with preeclampsia (PE group) and normal pregnancy controls (NP group) were included according to the guidelines of the American College of Obstetricians and Gynecologists (ACOG). The serum levels of malondialdehyde (MDA), total antioxidant capacity, and nitric oxide (NO) were estimated, and the heart rate and mean arterial pressure were recorded. The gene profiling of NOS3 and NOS2 was performed through real-time polymerase chain reaction (RT-PCR). The statistical analysis was performed using the Student t-test, and values of p < 0.05 were considered statistically significant. The serum levels of malondialdehyde were increased (p < 0.0001), and the total antioxidant capacity was reduced in the PE group (p = 0.034), indicating oxidative stress. In the PE group, the mean arterial pressure was significantly higher (p < 0.0001), but the serum levels of NO did not show a statistically significant reduction (p = 0.20). The gene expression profiling of NOS3 and NOS2 revealed a down regulation in the PE group by 8.49 and 51.05 times respectively. Oxidative stress may lead to endothelial dysfunction, which could result in increased mean arterial pressure. Nitric oxide may play a role in this mechanism, but interactions with other vasoactive /biological substances cannot be overlooked, as the gene expression of NOS3 and NOS2 has been reduced.

Effects of Metal Nanoparticles and Other Preparative Materials in the Environment on Plants: From the Perspective of Improving Secondary Metabolites.

The influence of preparation material residues in wastewater and soil on plants has been paid more and more attention by researchers. Secondary metabolites play an important role in the application of plants. It was found that nanomaterials can increase the content of plant secondary metabolites in addition to their role in pharmaceutical preparations. For example, 800 mg/kg copper oxide nanoparticles (NPs) increased the content of p-coumaric acid in cucumber by 225 times. Nanoparticles can cause oxidative stress in plants, increase signal molecule, and upregulate the synthase gene expression, increasing the content of secondary metabolites. The increase of components such as polyphenols and total flavonoids may be related to oxidative stress. This paper reviews the application and mechanism of metal nanomaterials (Ag-NP, ZnO-NP, CeO2-NP, Cds-NP, Mn-NP, CuO-NP) in promoting the synthesis of secondary metabolites from plants. In addition, the effects of some other preparative materials (cyclodextrins and immobilized molds) on plant secondary metabolites are also involved. Finally, possible future research is discussed.

Salicylic Acid Enhances Adventitious Root and Aerenchyma Formation in Wheat under Waterlogged Conditions.

The present study investigated the role of salicylic acid (SA) in regulating morpho-anatomical adaptive responses of a wheat plant to waterlogging. Our pharmacological study showed that treatment of waterlogged wheat plants with exogenous SA promotes the formation axile roots and surface adventitious roots that originate from basal stem nodes, but inhibits their elongation, leading to the formation of a shallow root system. The treatment also enhanced axile root formation in non-waterlogged plants but with only slight reductions in their length and branch root formation. Exogenous SA enhanced the formation of root aerenchyma, a key anatomical adaptive response of plants to waterlogging. Consistent with these results, waterlogging enhanced SA content in the root via expression of specific isochorismate synthase (ICS; ICS1 and ICS2) and phenylalanine ammonia lyase (PAL; PAL4, PAL5 and PAL6) genes and in the stem nodes via expression of specific PAL (PAL5 and PAL6) genes. Although not to the same level observed in waterlogged plants, exogenous SA also induced aerenchyma formation in non-waterlogged plants. The findings of this study furthermore indicated that inhibition of ethylene synthesis in SA treated non-waterlogged and waterlogged plants does not have any effect on SA-induced emergence of axile and/or surface adventitious roots but represses SA-mediated induction of aerenchyma formation. These results highlight that the role of SA in promoting the development of axile and surface adventitious roots in waterlogged wheat plants is ethylene independent while the induction of aerenchyma formation by SA requires the presence of ethylene.

New insights into the role of chrysanthemum calcineurin B\u2013like interacting protein kinase CmCIPK23 in nitrate signaling in Arabidopsis roots

Nitrate is an important source of nitrogen and also acts as a signaling molecule to trigger numerous physiological, growth, and developmental processes throughout the life of the plant. Many nitrate transporters, transcription factors, and protein kinases participate in the regulation of nitrate signaling. Here, we identified a gene encoding the chrysanthemum calcineurin B-like interacting protein kinase CmCIPK23, which participates in nitrate signaling pathways. In Arabidopsis, overexpression of CmCIPK23 significantly decreased lateral root number and length and primary root length compared to the WT when grown on modified Murashige and Skoog medium with KNO3 as the sole nitrogen source (modified MS). The expression of nitrate-responsive genes differed significantly between CmCIPK23-overexpressing Arabidopsis (CmCIPK23-OE) and the WT after nitrate treatment. Nitrate content was significantly lower in CmCIPK23-OE roots, which may have resulted from reduced nitrate uptake at high external nitrate concentrations (≥ 1 mM). Nitrate reductase activity and the expression of nitrate reductase and glutamine synthase genes were lower in CmCIPK23-OE roots. We also found that CmCIPK23 interacted with the transcription factor CmTGA1, whose Arabidopsis homolog regulates the nitrate response. We inferred that CmCIPK23 overexpression influences root development on modified MS medium, as well as root nitrate uptake and assimilation at high external nitrate supply. These findings offer new perspectives on the mechanisms by which the chrysanthemum CBL interacting protein kinase CmCIPK23 influences nitrate signaling.

Development of Optogenetic Dual-Switch System for Rewiring Metabolic Flux for Polyhydroxybutyrate Production.

Several strategies, including inducer addition and biosensor use, have been developed for dynamical regulation. However, the toxicity, cost, and inflexibility of existing strategies have created a demand for superior technology. In this study, we designed an optogenetic dual-switch system and applied it to increase polyhydroxybutyrate (PHB) production. First, an optimized chromatic acclimation sensor/regulator (RBS10–CcaS#10–CcaR) system (comprising an optimized ribosomal binding site (RBS), light sensory protein CcaS, and response regulator CcaR) was selected for a wide sensing range of approximately 10-fold between green-light activation and red-light repression. The RBS10–CcaS#10–CcaR system was combined with a blue light-activated YF1–FixJ–PhlF system (containing histidine kinase YF1, response regulator FixJ, and repressor PhlF) engineered with reduced crosstalk. Finally, the optogenetic dual-switch system was used to rewire the metabolic flux for PHB production by regulating the sequences and intervals of the citrate synthase gene (gltA) and PHB synthesis gene (phbCAB) expression. Consequently, the strain RBS34, which has high gltA expression and a time lag of 3 h, achieved the highest PHB content of 16.6 wt%, which was approximately 3-fold that of F34 (expressed at 0 h). The results indicate that the optogenetic dual-switch system was verified as a practical and convenient tool for increasing PHB production.