Degradation Of Salicylic Acid Research Articles

Ionizing radiation induced degradation of salicylic acid in aqueous solution

The radiation-induced degradation of salicylic acid (SA–) in aqueous solutions (1.0 and 0.1 mmol dm−3) saturated with N2O or air or without oxygen were studied. Irradiation was carried out using a cobalt-60 source. With a 1 mmol dm−3 solution saturated with N2O a seemingly total degradation occurred at about 18 kGy, although small quantities of 2,3-dihydroxybenzoic acid, catechol and 2,5-dihydroxybenzoic acid were present at that dose at concentrations of 67, 22 and 6 μmol dm−3 respectively. Under air and when free oxygen, the three radiolytic products were present at 18.54 kGy while SA– was destroyed only to 90% and 62%, respectively. In the case of 0.1 mmol dm−3 SA– solutions, the acid was degraded at 3.5 kGy if the solution contained N2O, at 5.8 kGy in air and at 7 kGy without oxygen. The concentration of the radiolytic products increased with increasing dose and after a maximum they decreased. The oxidation was followed by measuring the chemical oxygen demand; the slopes were 0.48 and 0.11, 0.21 and 0.07, 0.15 and 0.03 mmol dm−3 kGy−1 for 1.0 and 0.10 mmol dm−3 solutions saturated with N2O or air or without oxygen, respectively.

Fluorine recovery from etching wastewater through CaF2-based near-infrared photocatalyst synthesis

Fluorine in etching wastewater is an important F resource, and the development of a high value-added fluorine based compounds could benefit for the fluoride resource saving and the reduction of fluoride effluent. In this work, F from etching wastewater was recovered by composites of CaF2 and CaSO4, which was used to prepare as the near infrared photocatalyst of Tm3+/Yb3+ co-doped ((CaF2/CaWO4)@Bi2WO6) (TY-CCB). It was found that CaWO4 was fabricated by the slow release of Ca2+ ions from CaSO4 particles according to XRD and XPS results, and the heterostructure between CaWO4 and Bi2WO6 were formed in the TY-CCB composite with flat-shape morphology, which could improve the photocatalytic activity. The upconverted UV (364 nm) and blue (484 nm) light were observed upon 980 nm NIR irradiation, combined with the extended absorption band of 519 nm in TY-CCB. For the degradation of methyl orange (MO) and salicylic acid (SA), the corresponding degradation rate of 0.44 and 0.42 mg L−1·h−1 were obtained after 3 h under NIR light irradiations, and both of them increased to 2.78 and 1.74 mg L−1·h−1 under UV–vis–NIR light irradiations, respectively. Fluorine recovery through the preparation of TY-CCB upconversion photocatalyst was a mutually beneficial approach.

Green synthesis of I− ions doped (BiO)2CO3 with enhanced visible-light photocatalytic activity

I− ions doped (BiO)2CO3 (denoted as I-BOC) was prepared by a facile and rapid solid-state chemical reaction route. As compared to pure BOC, the I-BOC exhibited excellent visible-light-driven photocatalytic activity for rhodamine B (RhB) degradation even when RhB concentration reached 20 mg/L (catalyst, 0.4 g/L). Furthermore, the as-prepared I-BOC also exhibited good visible light photocatalytic activity for the degradation of methylene blue (MB), crystal violet (CV) and salicylic acid (SA). The investigation on the photocatalytic mechanism indicated that the doping of I− ions decreased the particles size and band gap simultaneously, which resulted in an increase in the exposed active centers and visible light absorption range, thus enhancing visible light photoactivity.

Photoelectrocatalytic activity of immobilized Fe2O3 photoelectrode for degradation of salicylic acid and methyl orange dye under visible light illumination

Fe2O3 thin films have been successfully synthesized by chemical spray pyrolysis technique. The effect of solution quantities onto the photoelectrochemical (PEC), structural, morphological, and optical properties has been studied. Film prepared at 50 ml solution quantity shows the maximum photoelectrochemical performance in 0.1 M NaOH electrolyte. X-ray diffraction studies reveal that the synthesized Fe2O3 thin films are polycrystalline with rhombohedral crystal structure. The surface morphology of Fe2O3 thin films shows that needle-shaped grains have slowly converted into round-shaped grains. The estimated band gap energy of Fe2O3 films varies from 2.02 to 2.15 eV with respect to quantities of spraying solution and it exhibits absorption in visible region. The photoelectrocatalytic degradation process shows better removal efficiency of organic compounds as compared to photocatalytic process for degradation of salicylic acid (SA) using large area (100 cm2) Fe2O3 photoelectrode under visible light illumination. Further, photoelectrocatalytic degradation process have been employed for degradation of colorant organic compound such as methyl orange (MO) dye.

Novel synthesis method for photo-catalytic system based on some 3d-metal titanates

In this paper, we studied titanium (TiO2) nanoparticle in three different structures (Anatase, Rutile, and Degussa) and then they were synthesized by the sol–gel method which is used butanol, toluene, and triethylene glycol as solvent at different temperatures and times. Then in this case to modify the TiO2, doping was done by transition metals and CdTiO3, CrTiO3, NiTiO3, MnTiO3, FeTiO3, and CoTiO3 were synthesized. The pure MTiO3 (M = Cd, Cr, Ni, Mn, Fe and Co) nanoparticles were formed when the precursor was heat-treated at 750 °C for 210 min. Characterizing the new additions was conducted by X-ray diffraction, FT-IR spectroscopy, UV–Vis spectroscopy, Scanning electron microscopy (SEM) image and N2 absorption–desorption. The BET analysis was performed to calculate the specific surface area. Pore diameter, pore volume, and the percentage of mesoporous MTiO3 were obtained by the BJH method according to the reaction. Titanium(IV) butoxide as a precursor was reacted with the metals and the energy band gap based on the metals decreased markedly and differently. To show the existing bond of titanium and metals, FT-IR and SEM image were used to investigate the obtained addition and investigating better their morphology respectively. To evaluate the photocatalytic properties of the nanocrystalline TiO2 (Degussa P-25) and MTiO3, the photocatalytic degradation of salicylic acid as a chemical toxic compound under ultraviolet light irradiation was carried out.

Enhanced photocatalytic ozonation degradation of organic pollutants by ZnO modified TiO2 nanocomposites

Advanced oxidation processes (AOPs) for wastewater treatment have attracted much attention for their efficient capability in destroying persistent and toxic organic compounds. In this study, we reported a simple impregnation-calcination method to fabricate ZnO modified TiO2 (Zn-TiO2) nanocomposites and employed them as catalysts for degradation of organic pollutants in water. The results show that 7at%Zn-TiO2 exhibits much better performances of photocatalysis, catalytic ozonation and photocatalytic ozonation than pure TiO2, which could be due to its richer surface hydroxyl groups and higher separation efficiency of photogenerated electron-hole pairs. The total organic carbon (TOC) removal efficiency of salicylic acid (SA) in UV/O3/7at%Zn-TiO2 is higher than the sum of those in UV/7at%Zn-TiO2 and O3 processes, indicative of a synergistic effect between photocatalysis and ozonation. Mechanism studies demonstrate that the active species such as H2O2, h+, OH, O2− and 1O2 are responsible for SA degradation. Meanwhile, the intermediates of SA mineralization were identified by HPLC–MS and its mineralization pathway was proposed. Reusability test verifies a high stability of 7at%Zn-TiO2 in the photocatalytic ozonation process, and the catalyst can be applied in a wide pH range of aqueous solution from 3.5 to 10.0. This work puts forward a new application of the easily available Zn-TiO2 nanocomposites and might drive the advance of photocatalytic ozonation approach for water purification.

Fe doped CeO2 nanosheets as Fenton-like heterogeneous catalysts for degradation of salicylic acid

Fe doped CeO2 nanosheets with various Fe/Ce ratios were synthesized by solvothermal method (ST) and catalytic performances were evaluated by the degradation of salicylic acid (SA) in the presence of H2O2 (Fenton-like oxidation). The Fe-CeO2 mixed oxides were characterized by SEM, TEM, XRD, EPR, Raman, H2-TPR and XPS, which indicated that 2% Fe doped CeO2 nanosheets (2Fe-CeO2) showed the largest concentration of surface oxygen vacancies and the highest catalytic activity under the optimum reaction conditions due to the complex adsorption of SA and H2O2 on the surface Ce3+. DMPO spin trapping EPR studies and analysis of intermediate products by LC-MS indicated that superoxide species (O2−/HOO) played a crucial role in the oxidation degradation process, meanwhile, the probable pathway of SA degradation was proposed. The strong adsorption of not-fully degraded low molecular weight organic acids (LMWOAs) on the active sites decreased the reusability of 2Fe-CeO2 catalyst, however, the catalytic activities could be recovered by a simple calcination treatment in air atmosphere.

Enhanced co-catalytic effect of Cu-Ag bimetallic core-shell nanocomposites imparted to TiO2 under visible light illumination

This paper signifies that the bimetallic (BM) coinage metal NCs deposited on TiO2 possess the ability to absorb visible light in a wide wavelength range and are also expected to display the new properties due to synergy between two distinct metals. As a result, they reveal highest level of activity than the monometallics deposited on TiO2. In this respect, the core@shell (Cu@Ag), inverse core@shell (Ag@Cu) BM NCs and their monometallics modified TiO2 have been relatively investigated for the optical absorption, emission, charge carrier dynamics, surface structural morphology and photocatalytic activity under visible light irradiation. A significant blue-shift in the SP band of Cu@Ag and a red-shift in Ag@Cu with notable color change were observed due to their composition change and morphology. Further, the TEM analysis also revealed the formation of eccentric core-shell Cu@Ag and uniform core@shell Ag@Cu BM NCs which were deposited on TiO2, evidenced by diffuse reflectance spectroscopy, EDX, photoluminescence and time resolved spectroscopy. The visible light irradiation on core@shell BM-TiO2 promoted ~ 3 times higher reduction of 3-nitroacetophenone and 1-chloro-3-nitrobenzene and ~2 times higher degradation of salicylic acid as compared to monometallic-TiO2. This can be attributed to the decrease in work function of resulting Cu-Ag BM NCs (ca. 3.8–4.6eV) relative to their individual particles (4.3–5.3eV) that lower the height of Schottky barrier created at the core@shell BM-TiO2 heterojunction. As a result, this led to the efficient electron transfer from the BM NCs to TiO2, resulting in enhanced photocatalytic activity than the monometallic-TiO2.

One-pot synthesis of belt-like Bi2S3/BiOCl hierarchical composites with enhanced visible light photocatalytic activity

One-dimensional (1D) belt-like Bi2S3/BiOCl composites were synthesized by a facile one-pot solvothermal method, using bismuth subsalicylate as the Bi source and, in particular, as the morphological template. The synthesized composites were characterized by many techniques, such as XRD, SEM, XPS, TEM and UV–vis diffuse reflectance and photoluminescence spectra. Photocatalytic activity of the composites was evaluated via catalytic degradation of salicylic acid (SA) and Rhodamine B (RhB) under visible light irradiation. The belt-like composites show a heterojunction structure in which the Bi2S3 nanoparticles are uniformly dispersed in the BiOCl matrix with dominant exposed (010) facets. They exhibit enhanced photodegradation efficiency in comparison with pure belt-like Bi2S3 and BiOCl. With increasing Bi2S3 content, the photodegradation efficiency of the composites increases then decreases. The Bi2S3/BiOCl composite with a Bi2S3 content of ∼2% exhibits the highest photocatalytic activity. The apparent first-order photodegradation rate constants of the composite for SA (∼0.048h−1) and RhB (∼0.299min−1) are significantly higher than those of the pure BiOCl and Bi2S3 for SA (∼0 and ∼0.0007h−1) and RhB (∼0.102 and ∼0.002min−1), respectively. The enhancement in photocatalytic activity is attributed to the efficient separation of photoinduced electrons and holes along with the increased specific surface area and visible-light absorption. The holes and superoxide radicals are the major active species. In addition, the belt-like Bi2S3/BiOCl photocatalysts exhibit excellent stability and reusability. This work provides a facile strategy for synthesis of 1D hierarchical Bi-based composite photocatalysts, and demonstrates the potential of belt-like Bi2S3/BiOCl composites for application in environmental remediation.

Effect of dopants on the structure of titanium oxide used as a photocatalyst for the removal of emergent contaminants

Abstract Photocatalysts composed of titanium dioxide modified with B, F, N and P have been synthesized, characterized and applied to the degradation of caffeine, diclofenac, ibuprofen and salicylic acid. The modified TiO2 samples were prepared by the sol–gel technique starting from titanium(IV) isopropoxide and using H3BO3, NH4F, N(C2H5OH)3 and H3PO4 as precursors of the modifiers, with the content varying between 0 and 5 wt%. Structural characterization was based on nitrogen physisorption at −196 °C, powder X-ray diffraction (PXRD), simultaneous thermogravimetric/differential thermal analysis (TG/DTA) and X-ray photoelectron spectroscopy (XPS). The structural properties of the modified TiO2 solids were significantly different depending on the nature and amount of modifiers and the calcination temperature. TiO2 in the anatase phase was obtained in all cases and was stable upon calcination at 400 °C. The photocatalytic degradation of caffeine, diclofenac, ibuprofen and salicylic acid by modified TiO2 was investigated under ultraviolet irradiation at 25 °C. The photocatalytic degradation behavior followed the order: caffeine > diclofenac = ibuprofen > salicylic acid. B-doped TiO2 was the most efficient catalyst in the degradation of these selected emerging contaminants.

Photocatalytic degradation of salicylic acid with magnetic activated carbon-supported F-N codoped TiO2 under visible light

In this work, magnetically separable F-N co-doped TiO2 were synthesized using a facile sol-gel method grafted on magnetic activated carbon decorated with carbonized chitosan (F-N-TiO2/MAC-CTS). The composite photocatalysts were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), the N2 adsorption/desorption method (BET), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometry (VSM). The usage of hydrofluoric acid (HF) as F precursor could modify the morphology, crystalline size, specific surface area and energy bandgaps of the photocatalysts. Photocatalysts with different molar ratio of F:Ti turned out to show different photocatalytic ability for salicylic acid (SA). The highest degradation rate of 61.99% was achieved for samples with molar ratio (F:Ti) of 0.1 after 3 h visible light irradiation. The rate constant of F0.1-N-TiO2/MAC-CTS was 0.00532 min−1, which was about 2.5 times higher compared with photocatalyst doped with N only. Results of quenching experiment showed that ·OH and h+ played major roles in the photocatalysis. F0.1-N-TiO2/MAC-CTS still remained good photocatalytic activity after 4 times of recycling experiments.

Over-expression of SlJA2 decreased heat tolerance of transgenic tobacco plants via salicylic acid pathway.

Over-expression of SlJA2 decreased the accumulation of SA, which resulted in significant physiological and gene expression changes in transgenic tobacco plants, leading to the decreased heat tolerance of transgenic tobacco. NAC family, the largest transcription factors in plants, responses to different environmental stimuli. Here, we isolated a typical NAC transcription factor (SlJA2) from tomato and got transgenic tobacco with SlJA2 over-expression. Expression of SlJA2 was induced by heat stress (42 °C), chilling stress (4 °C), drought stress, osmotic stress, abscisic acid, and salicylic acid. Over-expression of SlJA2 decreased the accumulation of salicylic acid by regulating expression of salicylic acid degradation gene under heat stress. Compared to WT plants, stomatal apertures and water loss increased in transgenic plants, and the damage of photosynthetic apparatus and chlorophyll breakdown were more serious in transgenic plants under heat stress. Meanwhile, more H2O2 and O2·- were accumulated transgenic plants and proline synthesis was restricted, which resulted in more serious oxidative damage compared to WT. qRT-PCR analysis showed that over-expression of SlJA2 could down-regulate genes involved in reactive oxygen species scavenging, proline biosynthesis, and response to heat stress. All the above results indicated that SlJA2 may be a negative regulator responded to plant's heat tolerance. Thus, this study provides new insight into roles of NAC family member in plant response to abiotic stress.

In situ construction of a novel Bi/CdS nanocomposite with enhanced visible light photocatalytic performance

A novel Bi/CdS nanocomposite is obtained via an in-situ chemical reduction method under mild conditions. The incorporation of Bi nanostructure can significantly enhance the photocatalytic performance for methyl orange (MO) and salicylic acid (SA) degradation compared with pristine CdS under visible light irradiation. The dramatically improved photoactivity can be attributed to the enhanced light absorption and optimized charge separation. In addition, the photocatalysis mechanism upon Bi/CdS for MO degradation is also investigated. This study is hoped to provide a new inspiration for the construction of high-efficiency semimetal/semiconductor photocatalysts, especially for non-noble metal/MxSy nanocomposites.

UV Light-Assisted Degradation of Methyl Orange, Methylene Blue, Phenol, Salicylic Acid, and Rhodamine B: Photolysis Versus Photocatalyis

Methyl orange (MO), methylene blue (MB), phenol (F), salicylic acid (SA), and rhodamine B (ROD) were used as substrates during the photodegradation experiments in the absence and in the presence of nanostructured Ag/titania-silica. The catalyst was characterized by scanning electron microscopy (SEM), scanning transmission electron microscope high-angle annular dark field (STEM-HAADF), stereological analysis, nitrogen adsorption-desorption, and X-ray photoelectron spectroscopy (XPS) measurements. The results were fitted on pseudo-first and pseudo-second kinetic order models. The film diffusion was also determined. The photolysis degrades MO and F to a greater extent than the photocatalysis. The degradation of SA occurred at the same rate either by photolysis or by photocatalysis. MB was best removed by photocatalysis. With regard to the photocatalysis, the highest rates of film diffusion were obtained for MB, F, and ROD, meaning that these molecules crossed the film to arrive at the catalyst surface more rapidly than the others. For MO and MB, the results followed the pseudo-first-order kinetic model while for SA, F, and ROD, the pseudo-second-order kinetic model was more appropriate.

Kinetic study of salicylic acid photocatalytic degradation using sol–gel anatase thin film with enhanced long-term activity

The scope of this work was to evaluate the photocatalytic degradation of salicylic acid (SA) using the anatase TiO2 thin film (hereafter: ATF) under UV-A irradiation and to explore the tentative long-term activity of ATF. The ATF was immobilized by the sol–gel procedure on the inner side of outer wall of annular glass reactor for maximized exposure area to applied irradiation. The ATF was used for 41 consecutive photocatalytic runs (trun = 60 min) and then irradiated under natural sunlight over a period of 15 days. Photocatalytic runs were repeated with irradiated catalyst, showing the unchanged photocatalytic activity with observed reaction rate constant k SA,obs = 4.0 × 10−7 min−1 W−0.5 m1.5. The degradation and mineralization kinetics of SA and the degradation by-products were studied. A tentative reaction scheme was presented. 2,5-Dihydroxybenzoic acid (2,5-DHBA) and 2,3-dihydroxybenzoic acid (2,3-DHBA) were identified as the main degradation by-products. The incident photon flux was determined along the inner reactor wall, i.e. on the thin film surface (I tf, W m−2) using two radiation emission models. To obtain kinetic parameters independently of photocatalyst optical properties and irradiation conditions, its lump value was introduced to kinetic model. A detailed kinetic study revealed first-order kinetics for SA, 2,5-DHBA, 2,3-DHBA and residual organics degradation and confirmed the preferred degradation pathway via ·OH radical attack.

Enhancement of emerging contaminants removal using Fenton reaction driven by H2O2-producing microbial fuel cells

The discharge of emerging contaminants (ECs) into the environment has raised great concerns due to their negative effects on the ecosystem. Intensive research efforts have been undertaken in order to find effective methods to treat these compounds. In this study, the removal of four ECs including Bisphenol A (BPA), Estrone (E1), Sulfamethazine (SM2), Triclocarban (TCC) was investigated in the microbial fuel cell (MFC)-Fenton system. Glucose and graphite rod with stacked graphite granules were used as the substrate and electrode, respectively since they improved current density of MFCs system and increased cathodic H2O2 synthesis. Both batch and continuous flow modes of MFCs were compared and the operational parameters for higher H2O2 yield were also studied. The results showed that for both batch and continuous flow modes, initially the H2O2 production had a rising trend and arrived at the highest level but subsequently it decreased. We later demonstrated that controlling pH at 3 would promote H2O2 accumulation. Integrating the in-situ H2O2 synthesis and Fe2+ addition in the cathodic chamber, production of hydroxyl radicals was evidenced through salicylic acid degradation and formation of its hydroxyl products. The MFC-Fenton system could effectively remove E1, BPA, TCC and SM2. Our results showed that the removal of ECs was attributed to the oxidation by OH and the adsorption on graphite materials. The contribution of the two removal mechanisms to the overall removal will vary with different ECs depending on the ECs reactivity in Fenton reaction. This study demonstrates the application of the MFC-Fenton technology to effectively remove E1, BPA, TCC and SM2, which provides a promising and cost-effective alternative for future ECs removal.

Activated carbon-based magnetic TiO2 photocatalyst codoped with iodine and nitrogen for organic pollution degradation

Magnetic photocatalyst − iodine and nitrogen codoped TiO2 based on chitosan decorated magnetic activated carbon (I-N-T/CMAC) was prepared via simple coprecipitation and sol-gel method. The characteristics of photocatalysts were investigated by X-ray diffraction (XRD), N2 adsorption–desorption isotherm, field emission scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflection spectroscopy (UV–vis DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM). It turned out that the prepared material had large surface area, enhanced absorption of visible light, and magnetically separable properties when mole ratio of I/Ti was 0.1. Iodine-nitrogen codoped magnetic photocatalyst was used for the removal of salicylic acid (SA), and the rate of adsorption reaction for SA by I0.1-N-T/CMAC followed the pseudo second-order kinetic. Under visible light irradiation, 89.71% SA with initial concentration=30mg/L could be removed by I0.1-N-T/CMAC, and photodegradation rate of SA on I0.1-N-T/CMAC composites was 0.0084min−1 which is about 4 times higher than that of magnetic photocatalyst with nitrogen doped only. The effects of SA initial concentration, pH, coexisting anions and humic acid to the degradation of SA with the prepared material were also investigated. Main oxidative species in the photodegradation process are OH and h+.

Phytohormone sensing in the biotrophic fungus Ustilago maydis - the dual role of the transcription factor Rss1.

SummaryThe phenolic compound salicylic acid (SA) is a key signalling molecule regulating local and systemic plant defense responses, mainly against biotrophs. Many microbial organisms, including pathogens, share the ability to degrade SA. However, the mechanism by which they perceive SA is unknown. Here we show that Ustilago maydis, the causal agent of corn smut disease, employs a so far uncharacterized SA sensing mechanism. We identified and characterized the novel SA sensing regulator, Rss1, a binuclear zinc cluster protein with dual functions as putative SA receptor and transcriptional activator regulating genes important for SA and tryptophan degradation. Rss1 represents a major component in the identified SA sensing pathway during the fungus’ saprophytic stage. However, Rss1 does not have a detectable impact on virulence. The data presented in this work indicate that alternative or redundant sensing cascades exist that regulate the expression of SA‐responsive genes in U. maydis during its pathogenic development.

Photocatalytic Degradation of Salicylic Acid and Reduction of Cr(VI) using TiO2

Photocatalytic Degradation of Salicylic Acid and Reduction of Cr(VI) using TiO2

Degradation of the Plant Defense Signal Salicylic Acid Protects Ralstonia solanacearum from Toxicity and Enhances Virulence on Tobacco.

ABSTRACTPlants use the signaling molecule salicylic acid (SA) to trigger defenses against diverse pathogens, including the bacterial wilt pathogen Ralstonia solanacearum. SA can also inhibit microbial growth. Most sequenced strains of the heterogeneous R. solanacearum species complex can degrade SA via gentisic acid to pyruvate and fumarate. R. solanacearum strain GMI1000 expresses this SA degradation pathway during tomato pathogenesis. Transcriptional analysis revealed that subinhibitory SA levels induced expression of the SA degradation pathway, toxin efflux pumps, and some general stress responses. Interestingly, SA treatment repressed expression of virulence factors, including the type III secretion system, suggesting that this pathogen may suppress virulence functions when stressed. A GMI1000 mutant lacking SA degradation activity was much more susceptible to SA toxicity but retained the wild-type colonization ability and virulence on tomato. This may be because SA is less important than gentisic acid in tomato defense signaling. However, another host, tobacco, responds strongly to SA. To test the hypothesis that SA degradation contributes to virulence on tobacco, we measured the effect of adding this pathway to the tobacco-pathogenic R. solanacearum strain K60, which lacks SA degradation genes. Ectopic addition of the GMI1000 SA degradation locus, including adjacent genes encoding two porins and a LysR-type transcriptional regulator, significantly increased the virulence of strain K60 on tobacco. Together, these results suggest that R. solanacearum degrades plant SA to protect itself from inhibitory levels of this compound and also to enhance its virulence on plant hosts like tobacco that use SA as a defense signal molecule.