The Obesity-Related Metabolic Gene HSD17B8 Protects Against Breast Cancer: High RNA/Protein Expression Means a Better Prognosis.

BACKGROUND The incidence of breast cancer is increasing annually. Obesity and metabolism are considered risk factors for breast cancer. Discovery of obesity- and metabolism-related breast cancer prognostic genes is imminent. MATERIAL AND METHODS We screened metabolism-related genes (MRG) from KEGG and downloaded the obese female dataset GSE151839 from GEO, which screened differentially-expressed genes (DEGs), seen as female obesity-related genes. The intersection of MRGs and DEGs was obesity-related metabolic genes (OMGs), verified by enrichment analysis. After downloading breast cancer data from TCGA, univariate Cox regression and log-rank P analyses were used to screen hub OMGs related to breast cancer prognosis. ROC curve and Kaplan-Meier (KM) plotter, GEPIA, and GENT2 databases were used to verify the hub OMGs at the RNA level. CPTAC and HLA databases were used to verify the hub OMGs at the protein level. RESULTS We screened 33 OMGs. The results of univariate Cox regression and log-rank P analysis showed 3 of 33 OMGs (ABCA1, LPIN1, HSD17B8) were associated with the prognosis of breast cancer patients. After verification with ROC, KM-plotter, and GEPIA, only HSD17B8 was related to breast cancer prognosis (overall/disease-free survival). Results of GENT2 showed the RNA expression of HSD17B8 in breast cancer subtypes with poor prognosis is significantly lower than that with good prognosis. Results of CPTAC and HLA databases showed that the protein expression level of HSD17B8 in breast cancer tissues was significantly lower than that in adjacent normal tissues. CONCLUSIONS HSD17B8 is a protective gene against breast cancer. The higher the expression of HSD17B8, the better the prognosis of breast cancer patients.

Overexpressing STAMP2 attenuates diabetic renal injuries via upregulating autophagy in diabetic rats.

Diabetic nephropathy (DN) is one of the most serious and major renal complications of diabetes. Previously, Six-transmembrane Protein of Prostate 2 (STAMP2) was reported to contribute to nutritional stress. The purpose of this study is to investigate whether overexpression of STAMP2 attenuates diabetic renal injuries in DN rats. We induced the DN rat model by high-fat diet and low-dose streptozotocin and evaluated the metabolite and urine albumin/creatinine. Recombinant adeno-associated virus vectors were injected for overexpression of STAMP2. Pathophysiologic and ultrastructure features of DN by histochemical stain and transmission electron microscope, autophagy-related proteins and signaling pathway by western blotting were assessed. We found the expression of STAMP2 was decreased and autophagy was blunted in DN rat kidneys. Overexpressing STAMP2 significantly ameliorated metabolic disturbance, insulin resistance, and specifically restoring diabetic renal injury. Furthermore, overexpressing STAMP2 improved the autophagy deficiency in DN rats, as revealed by changes in the expressions of Beclin1, p62, and LC3. Furthermore, STAMP2 overexpressing promoted autophagy by inhibiting the mTOR and activating the AMPK/SIRT1 signaling pathway. Our results suggested that STAMP2 overexpression attenuated renal injuries via upregulating autophagy in DN rats. STAMP2 overexpressing promoted autophagy may been involved with inhibition of the mTOR/ULK1 and activation of the AMPK/SIRT1 signaling pathway.

Conserved Pigment Profiles in Phylogenetically Diverse Symbiotic Bacteria Associated with the Corals Montastraea cavernosa and Mussismilia braziliensis.

Pigmented bacterial symbionts play major roles in the health of coral holobionts. However, there is scarce knowledge on the diversity of these microbes for several coral species. To gain further insights into holobiont health, pigmented bacterial isolates of Fabibacter pacificus (Bacteroidetes; n = 4), Paracoccus marcusii (Alphaproteobacteria; n = 1), and Pseudoalteromonas shioyasakiensis (Gammaproteobacteria; n = 1) were obtained from the corals Mussismilia braziliensis and Montastraea cavernosa in Abrolhos Bank, Brazil. Cultures of these bacterial symbionts produced strong antioxidant activity (catalase, peroxidase, and oxidase). To explore these bacterial isolates further, we identified their major pigments by HPLC and mass spectrometry. The six phylogenetically diverse symbionts had similar pigment patterns and produced myxol and keto-carotene. In addition, similar carotenoid gene clusters were confirmed in the whole genome sequences of these symbionts, which reinforce their antioxidant potential. This study highlights the possible roles of bacterial symbionts in Montastraea and Mussismilia holobionts.

Developmental toxicity, antioxidant, and marker enzyme assessment of swertiamarin in zebrafish (Danio rerio).

A secoiridoid glycoside called swertiamarin has been widely used as a herbal medicine for many decades. In particular, swertiamarin from the Enicostema axillare herb has been used as a multipurpose drug to treat innumerable health problems. As this medicine is consumed orally, its toxicity level should be determined. To examine the safety of this compound, toxicology work was done in zebrafish, and this is the first report to describe swertiamarin toxicity in zebrafish. Zebrafish embryos were used in this swertiamarin toxicity study, and morphological changes were observed. Further, the compound was also studied in adult zebrafish to determine the impact of the compound on the fish liver. Enzyme profiling with superoxide dismutase, glutathione peroxidase, catalase, reduced glutathione levels, glutathione S-transferase, lactate dehydrogenase, glutamic oxaloacetic transaminases, lipid peroxidation, Na+ /K+ -ATPase, and glutamic pyruvic transaminases) was evaluated (p ≤ 0.05). Results suggest that swertiamarin is a safe drug only at a low concentration (40 µM). This study also shows that even herbal medicinal compounds may be toxic to humans at higher dosages. Hence, irrespective of whether a drug is synthetic or natural, it needs to be tested for its toxicity before use in humans.

Coaction of hepatic thioredoxin and glutathione systems in iron overload-induced oxidative stress.

In the present study, we demonstrate the coaction of thioredoxin and glutathione (GSH) systems in mouse liver against iron overload-induced oxidative stress (OS). Mice were injected intraperitoneally with an iron dextran solution twice a week for 3 weeks. Iron accumulation in mouse liver was demonstrated spectroscopically. To confirm the iron overload model in the liver, the increased gene expression levels of hepcidin (Hamp), ferroportin (Fpn1), and ferritin (Fth1), which regulate iron trafficking, were observed by a quantitative polymerase chain reaction. In the case of iron overload, the GSH level and the reduced glutathione/oxidized glutathione ratio, which represents a marker of OS, decreased significantly. An increase in the malondialdehyde level, one of the final products of the lipid peroxidation process, was observed. The gene expression of the thioredoxin system, including thioredoxin (Trx1) and thioredoxin reductase (TrxR1), was examined. Though TrxR1 expression decreased, no changes were observed in Trx1. The enzyme activity and semiquantitative protein expression of TRXR1 increased. The activity of GSH reductase and GSH peroxidase increased in the iron overload group. The gene and protein expressions of thioredoxininteracting protein, which is an indicator of the commitment of the cell to apoptosis, were elevated significantly. The increased protein expression of Bcl-2-related X protein and CASPASE-3, which is an indicator of apoptosis, increased significantly. In conclusion, excess iron accumulation in mouse liver tissue causes OS, which affects the redox state of the thioredoxin and GSH systems, inducing cell apoptosis and also ferroptosis due to increased lipid peroxidation and the depletion of GSH level.

Impact of glycerol feeding profiles on STEAP1 biosynthesis by Komagataella pastoris using a methanol-inducible promoter.

Currently, the lack of reliable strategies for the diagnosis and treatment of cancer makes the identification and characterization of new therapeutic targets a pressing matter. Several studies have proposed the Six Transmembrane Epithelial Antigen of the Prostate 1 (STEAP1) as a promising therapeutic target for prostate cancer. Although structural and functional studies may provide deeper insights on the role of STEAP1 in cancer, such techniques require high amounts of purified protein through biotechnological processes. Based on the results presented, this work proposes the application, for the first time, of a fed-batch profile to improve STEAP1 biosynthesis in mini-bioreactor Komagataella pastoris X-33 Mut+ methanol-induced cultures, by evaluating three glycerol feeding profiles-constant, exponential, and gradient-during the pre-induction phase. Interestingly, different glycerol feeding profiles produced differently processed STEAP1. This platform was optimized using a combination of chemical chaperones for ensuring the structural stabilization and appropriate processing of the target protein. The supplementation of culture medium with 6 % (v/v) DMSO and 1 M proline onto a gradient glycerol/constant methanol feeding promoted increased biosynthesis levels of STEAP1 and minimized aggregation events. Deglycosylation assays with peptide N-glycosidase F showed that glycerol constant feed is associated with an N-glycosylated pattern of STEAP1. The biological activity of recombinant STEAP1 was also validated, once the protein enhanced the proliferation of LNCaP and PC3 cancer cells, in comparison with non-tumoral cell cultures. This methodology could be a crucial starting point for large-scale production of active and stable conformation of recombinant human STEAP1. Thus, it could open up new strategies to unveil the structural rearrangement of STEAP1 and to better understand the biological role of the protein in cancer onset and progression.

Distinct Effects of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus Cell Wall Component-Induced Inflammation on the Iron Metabolism of THP-1 Cells.

Macrophages are essential immune cells of the innate immune system. They participate in the development and regulation of inflammation. Macrophages play a fundamental role in fighting against bacterial infections by phagocytosis of bacteria, and they also have a specific role in immunomodulation by secreting pro-inflammatory cytokines. In bacterial infection, macrophages decrease the serum iron concentration by removing iron from the blood, acting as one of the most important regulatory cells of iron homeostasis. We examined whether the Gram-positive and Gram-negative cell wall components from various bacterial strains affect the cytokine production and iron transport, storage and utilization of THP-1 monocytes in different ways. We found that S. aureus lipoteichoic acid (LTA) was less effective in activating pro-inflammatory cytokine expression that may related to its effect on fractalkine production. LTA-treated cells increased iron uptake through divalent metal transporter-1, but did not elevate the expression of cytosolic and mitochondrial iron storage proteins, suggesting that the cells maintained iron efflux via the ferroportin iron exporter. E. coli and P. aeruginosa lipopolysaccharides (LPSs) acted similarly on THP-1 cells, but the rates of the alterations of the examined proteins were different. E. coli LPS was more effective in increasing the pro-inflammatory cytokine production, meanwhile it caused less dramatic alterations in iron metabolism. P. aeruginosa LPS-treated cells produced a smaller amount of pro-inflammatory cytokines, but caused remarkable elevation of both cytosolic and mitochondrial iron storage proteins and intracellular iron content compared to E. coli LPS. These results prove that LPS molecules from different bacterial sources alter diverse molecular mechanisms in macrophages that prepossess the outcome of the bacterial infection.

High-level production of industrially relevant oxidases by a two-stage fed-batch approach: overcoming catabolite repression in arabinose-inducible Escherichia coli systems.

With the growing interest in enzyme applications, there is an urgent demand for economic, affordable, and flexible enzyme production processes. In the present paper, we developed a high cell density fed-batch process for the production of two cofactor-containing oxidase, 5-hydroxymethylfurfural oxidase (HMFO) and eugenol oxidase (EUGO). The approach involved the arabinose-inducible system to drive the expression while using mineral media. In order to overcome a major drawback of arabinose-inducible promoters, carbon catabolite repression, (CCR) by glucose, we developed a high cell density culture (HCDC), two-stage fed-batch protocol allowing us to reach cell densities exceeding 70 g/L of dry cell weight (DCW) using glucose as carbon source. Then, induction was achieved by adding arabinose, while changing the carbon source to glycerol. This strategy allowed us to obtain an eightfold increase in recombinant HMFO titer when compared with a reference batch fermentation in Erlenmeyer flasks using terrific broth (TB), typically used with arabinose-inducible strains. The optimized protocol was also tested for expression of a structurally unrelated oxidase, EUGO, where a similar yield was achieved. Clearly, this two-step protocol in which a relatively cheap medium (when compared to TB) can be used reduces costs and provides a way to obtain protein production levels similar to those of IPTG-based systems. KEY POINTS: • Arabinose promoters are not well suited for HCDC production due to CCR effect. • This drawback has been overcome by using a two-stage Fed-batch protocol. • Protein yield has been increased by an eightfold factor, improving process economics.

Efficient synthesis of phycocyanobilin in mammalian cells for optogenetic control of cell signaling.

Optogenetics is a powerful tool to precisely manipulate cell signaling in space and time. For example, protein activity can be regulated by several light-induced dimerization (LID) systems. Among them, the phytochrome B (PhyB)-phytochrome-interacting factor (PIF) system is the only available LID system controlled by red and far-red lights. However, the PhyB-PIF system requires phycocyanobilin (PCB) or phytochromobilin as a chromophore, which must be artificially added to mammalian cells. Here, we report an expression vector that coexpresses HO1 and PcyA with Ferredoxin and Ferredoxin-NADP+ reductase for the efficient synthesis of PCB in the mitochondria of mammalian cells. An even higher intracellular PCB concentration was achieved by the depletion of biliverdin reductase A, which degrades PCB. The PCB synthesis and PhyB-PIF systems allowed us to optogenetically regulate intracellular signaling without any external supply of chromophores. Thus, we have provided a practical method for developing a fully genetically encoded PhyB-PIF system, which paves the way for its application to a living animal.

N2O production from hydroxylamine oxidation and corresponding hydroxylamine oxidoreductase involved in a heterotrophic nitrifier A. faecalis strain NR.

N2O production from NH2OH oxidation involved in a heterotrophic nitrifier Alcaligenes faecalis strain NR was studied. 15N-labeling experiments showed that biological NH2OH consumption by strain NR played a dominant role in N2O production, although chemical reaction between NH2OH and O2 indeed existed. Hydroxylamine oxidoreductase (HAO) from strain NR was partially purified by (NH4)2SO4 fractionation and DEAE Cartridge chromatography. The maximum activity of HAO was 9.60 mU with a specific activity of 92.04 mU/(mg protein) when K3Fe(CN)6 was used as an electron acceptor. The addition of Ca2+ promoted the HAO activity, while the presence of Mn2+ inhibited the enzyme activity. The optimal temperature and pH for HAO activity were 30 °C and 8. Analysis of enzyme-catalyzed products demonstrated that NH2OH oxidation catalyzed by HAO from strain NR played significant role in the production of N2O.

Identification and Functional Analysis of a Flavonol Synthase Gene from Grape Hyacinth.

Flavonols are important copigments that affect flower petal coloration. Flavonol synthase (FLS) catalyzes the conversion of dihydroflavonols to flavonols. In this study, we identified a FLS gene, MaFLS, expressed in petals of the ornamental monocot Muscari aucheri (grape hyacinth) and analyzed its spatial and temporal expression patterns. qRT-PCR analysis showed that MaFLS was predominantly expressed in the early stages of flower development. We next analyzed the in planta functions of MaFLS. Heterologous expression of MaFLS in Nicotiana tabacum (tobacco) resulted in a reduction in pigmentation in the petals, substantially inhibiting the expression of endogenous tobacco genes involved in anthocyanin biosynthesis (i.e., NtDFR, NtANS, and NtAN2) and upregulating the expression of NtFLS. The total anthocyanin content in the petals of the transformed tobacco plants was dramatically reduced, whereas the total flavonol content was increased. Our study suggests that MaFLS plays a key role in flavonol biosynthesis and flower coloration in grape hyacinth. Moreover, MaFLS may represent a new potential gene for molecular breeding of flower color modification and provide a basis for analyzing the effects of copigmentation on flower coloration in grape hyacinth.

Pseudomonas aeruginosa overexpression system of nitric oxide reductase for in vivo and in vitro mutational analyses.

Membrane-integrated nitric oxide reductase (NOR) reduces nitric oxide (NO) to nitrous oxide (N2O) with protons and electrons. This process is essential for the elimination of the cytotoxic NO that is produced from nitrite (NO2-) during microbial denitrification. A structure-guided mutagenesis of NOR is required to elucidate the mechanism for NOR-catalyzed NO reduction. We have already solved the crystal structure of cytochrome c-dependent NOR (cNOR) from Pseudomonas aeruginosa. In this study, we then constructed its expression system using cNOR-gene deficient and wild-type strains for further functional study. Characterizing the variants of the five conserved Glu residues located around the heme/non-heme iron active center allowed us to establish how the anaerobic growth rate of cNOR-deficient strains expressing cNOR variants correlates with the in vitro enzymatic activity of the variants. Since bacterial strains require active cNOR to eliminate cytotoxic NO and to survive under denitrification conditions, the anaerobic growth rate of a strain with a cNOR variant is a good indicator of NO decomposition capability of the variants and a marker for the screening of functionally important residues without protein purification. Using this in vivo screening system, we examined the residues lining the putative proton transfer pathways for NO reduction in cNOR, and found that the catalytic protons are likely transferred through the Glu57 located at the periplasmic protein surface. The homologous cNOR expression system developed here is an invaluable tool for facile identification of crucial residues in vivo, and for further in vitro functional and structural studies.

Cytochromes bd-I and bo3 are essential for the bactericidal effect of microcin J25 on Escherichia coli cells.

Microcin J25 has two targets in sensitive bacteria, the RNA polymerase, and the respiratory chain through inhibition of cellular respiration. In this work, the effect of microcin J25 in E. coli mutants that lack the terminal oxidases cytochrome bd-I and cytochrome bo3 was analyzed. The mutant strains lacking cytochrome bo3 or cytochrome bd-I were less sensitive to the peptide. In membranes obtained from the strain that only expresses cytochrome bd-I a great ROS overproduction was observed in the presence of microcin J25. Nevertheless, the oxygen consumption was less inhibited in this strain, probably because the oxygen is partially reduced to superoxide. There was no overproduction of ROS in membranes isolated from the mutant strain that only express cytochrome bo3 and the inhibition of the cellular respiration was similar to the wild type. It is concluded that both cytochromes bd-I and bo3 are affected by the peptide. The results establish for the first time a relationship between the terminal oxygen reductases and the mechanism of action of microcin J25.

Spontaneous up-regulation of SIRT1 during osteogenesis contributes to stem cells' resistance to oxidative stress.

Osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs) is a central event in bone formation. However, oxidative stress has a deleterious impact on BM-MSC osteogenesis. In this study, we hypothesized that oxidative stress influenced BM-MSC osteogenesis differently in the early or late stages, in which silent information regulator type 1 (SIRT1) played a critical role. A continuous exposure to sublethal concentrations of hydrogen peroxide (H2 O2 ), ranging from 25 to 100 µM for 21 days, resulted in the complete inhibition of BM-MSC osteogenesis. We found that a 7-day treatment with H2 O2 inhibited the lineage commitment of BM-MSCs toward osteoblasts, as evidenced by a significant reduction of alkaline phosphatase activity (a typical marker for early osteogenesis). However, moderate oxidative stress did not affect late-differentiated BM-MSCs, as there were comparable levels of matrix mineralization (a typical marker for late osteogenesis). In addition, we observed a spontaneous up-regulation of SIRT1 and intracellular antioxidant enzymes such as superoxide dismutase 2, catalase, and glutathione peroxidase 1, which accounted for the enhanced resistance to oxidative stress upon osteogenic differentiation. Activation of SIRT1 by resveratrol rescued the effect of H2 O2 on early-differentiated BM-MSCs and inhibition of SIRT1 by nicotinamide intensified the effect of H2 O2 on late-differentiated BM-MSCs, indicating that the SIRT1-mediated pathway was actively involved in MSC osteogenesis and antioxidant mechanisms. Our findings uncovered the relationship between SIRT1 and resistance to H2 O2 -induced oxidative stress during BM-MSC osteogenesis, which could provide a new strategy for protecting MSCs from extracellular oxidative stress.

Protein engineering of α-ketoisovalerate decarboxylase for improved isobutanol production in Synechocystis PCC 6803.

Protein engineering is a powerful tool to modify e.g. protein stability, activity and substrate selectivity. Heterologous expression of the enzyme α-ketoisovalerate decarboxylase (Kivd) in the unicellular cyanobacterium Synechocystis PCC 6803 results in cells producing isobutanol and 3-methyl-1-butanol, with Kivd identified as a potential bottleneck. In the present study, we used protein engineering of Kivd to improve isobutanol production in Synechocystis PCC 6803. Isobutanol is a flammable compound that can be used as a biofuel due to its high energy density and suitable physical and chemical properties. Single replacement, either Val461 to isoleucine or Ser286 to threonine, increased the Kivd activity significantly, both in vivo and in vitro resulting in increased overall production while isobutanol production was increased more than 3-methyl-1-butanol production. Moreover, among all the engineered strains examined, the strain with the combined modification V461I/S286T showed the highest (2.4 times) improvement of isobutanol-to-3M1B molar ratio, which was due to a decrease of the activity towards 3M1B production. Protein engineering of Kivd resulted in both enhanced total catalytic activity and preferential shift towards isobutanol production in Synechocystis PCC 6803.

Anaerobic production of medium-chain fatty alcohols via a ß-reduction pathway.

In this report, we identify the relevant factors to increase production of medium chain n-alcohols through an expanded view of the reverse ß-oxidation pathway. We began by creating a base strain capable of producing medium chain n-alcohols from glucose using a redox-balanced and growth-coupled metabolic engineering strategy. By dividing the heterologous enzymes in the pathway into different modules, we were able to identify and evaluate homologs of each enzyme within the pathway and identify several capable of enhancing medium chain alcohol titers and/or selectivity. In general, the identity of the trans-2-enoyl-CoA reductase (TER) and the direct overexpression of the thiolase (FadA) and ß-hydroxy-acyl-CoA reductase (FadB) improved alcohol titer and the identity of the FadBA complex influenced the dominant chain length. Next, we linked the anaerobically induced VHb promoter from Vitreoscilla hemoglobin to each gene to remove the need for chemical inducers and ensure robust expression. The highest performing strain with the autoinduced reverse ß-oxidation pathway produced n-alcohols at titers of 1.8 g/L with an apparent molar yield of 0.2 on glucose consumed in rich medium (52% of theoretical yield).

Reactive oxygen species dynamics in roots of salt sensitive and salt tolerant cultivars of rice.

Salinity stress is one of the major constraints for growth and survival of plants that affects rice productivity worldwide. Hence, in the present study, roots of two contrasting salinity sensitive cultivars, IR64 (IR64, salt sensitive) and Luna Suvarna (LS, salt tolerant) were compared with regard to the levels of reactive oxygen species (ROS) to derive clues for their differential salt stress adaptation mechanisms. In our investigation, the tolerant cultivar exhibited longer primary roots, more lateral roots, higher root number leading to increased root biomass, with respect to IR64. It was observed that LS roots maintained higher level of H2O2 in comparison to IR64. The activities of various enzymes involved in enzymatic antioxidant defense mechanism (SOD, CAT, GPX, DHAR and MDHAR) were found to be greater in LS roots. Further, the higher transcript level accumulation of genes encoding ROS generating (RbohA, RbohD and RbohE) and scavenging enzymes (Fe-SOD, Chloroplastic Cu/Zn-SOD, CAT and DHAR) were noticed in the roots of tolerant cultivar, LS. Moreover, the content of other stress markers such as total protein and proline were also elevated in LS roots. While, the expression of proline biosynthesis gene (P5CS) and proline catabolism gene (PDH) was observed to be lower in LS.

A VTVH MCD and EPR Spectroscopic Study of the Maturation of the "Second" Nitrogenase P-Cluster.

The P-cluster of the nitrogenase MoFe protein is a [ Fe8 S7] cluster that mediates efficient transfer of electrons to the active site for substrate reduction. Arguably the most complex homometallic FeS cluster found in nature, the biosynthetic mechanism of the P-cluster is of considerable theoretical and synthetic interest to chemists and biochemists alike. Previous studies have revealed a biphasic assembly mechanism of the two P-clusters in the MoFe protein upon incubation with Fe protein and ATP, in which the first P-cluster is formed through fast fusion of a pair of [ Fe4 S4]+ clusters within 5 min and the second P-cluster is formed through slow fusion of the second pair of [ Fe4 S4]+ clusters in a period of 2 h. Here we report a VTVH MCD and EPR spectroscopic study of the biosynthesis of the slow-forming, second P-cluster within the MoFe protein. Our results show that the first major step in the formation of the second P-cluster is the conversion of one of the precursor [ Fe4 S4]+ clusters into the integer spin cluster [ Fe4 S3-4]α, a process aided by the assembly protein NifZ, whereas the second major biosynthetic step appears to be the formation of a diamagnetic cluster with a possible structure of [ Fe8 S7-8]ß, which is eventually converted into the P-cluster.

Barley stripe mosaic virus (BSMV) as a virus-induced gene silencing vector in maize seedlings.

Barley stripe mosaic virus (BSMV) was the first reported and still widely used virus-induced gene silencing (VIGS) vector for monocotyledons including wheat and barley. Despite BSMV's reported infectivity on maize (Zea mays), the use of the virus as a vector in maize has not been optimized. Here, we assayed infectivity of BSMV in different maize cultivars by vascular puncture inoculation. Through knockdown of the endogenous host phytoene desaturase gene, we demonstrate for the first time that BSMV can be used as a VIGS vector in maize. This adds BSMV to the repertoire of tools available for functional studies in maize.