RESUMEN
Interplay of hormones with reactive oxygen species (ROS) fine-tunes the response of plants to stress; however, the crosstalk between brassinosteroids (BRs) and ROS in nematode resistance is unclear. In this study, we found that low BR biosynthesis or lack of BR receptor increased, whilst exogenous BR decreased the susceptibility of tomato plants to Meloidogyne incognita. Hormone quantification coupled with hormone mutant complementation experiments revealed that BR did not induce the defence response by triggering salicylic acid (SA), jasmonic acid/ethylene (JA/ET) or abscisic acid (ABA) signalling pathway. Notably, roots of BR-deficient plants had decreased apoplastic ROS accumulation, transcript of RESPIRATORY BURST OXIDASE HOMOLOG1 (RBOH1) and WHITEFLY INDUCED1 (WFI1), and reduced activation of mitogen-activated protein kinase 1/2 (MPK1/2) and MPK3. Silencing of RBOH1, WFI1, MPK1, MPK2 and MPK3 all increased the root susceptibility to nematode and attenuated BR-induced resistance against the nematode. Significantly, suppressed transcript of RBOH1 compromised BR-induced activation of MPK1/2 and MPK3. These results strongly suggest that RBOH-dependent MPK activation is involved in the BR-induced systemic resistance against the nematode.
Asunto(s)
Brasinoesteroides/metabolismo , Resistencia a la Enfermedad , Enfermedades de las Plantas/inmunología , Reguladores del Crecimiento de las Plantas/metabolismo , Proteínas de Plantas/metabolismo , Solanum lycopersicum/fisiología , Tylenchoidea/fisiología , Ácido Abscísico/metabolismo , Animales , Ciclopentanos/metabolismo , Etilenos/metabolismo , Regulación de la Expresión Génica de las Plantas , Solanum lycopersicum/enzimología , Solanum lycopersicum/genética , Solanum lycopersicum/inmunología , Proteínas Quinasas Activadas por Mitógenos/genética , Proteínas Quinasas Activadas por Mitógenos/metabolismo , NADPH Oxidasas/genética , NADPH Oxidasas/metabolismo , Oxilipinas/metabolismo , Enfermedades de las Plantas/parasitología , Proteínas de Plantas/genética , Especies Reactivas de Oxígeno/metabolismo , Ácido Salicílico/metabolismo , Transducción de SeñalRESUMEN
It is of great significance to search for efficient, renewable, biodegradable and economical membrane materials. Herein, we developed an organic-inorganic hybrid regenerated cellulose membrane (ZrO2/BCM) with excellent hydrophilic and anti-fouling properties. The membrane was prepared by introducing ZrO2 particles into an N-Methylmorpholine-N-oxide(NMMO)/bamboo cellulose(BC) solution system by the phase inversion method. The physi-chemical structure of the membranes were characterized based on thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (ATR-FTIR), field emission scanning electron microscopy (FE-SEM), and X-ray diffraction (XRD). The modified regenerated cellulose membrane has the excellent rejection of bovine serum albumin (BSA) and anti-fouling performance. The membrane flux of ZrO2/BCM is 321.49 (L/m2·h), and the rejection rate of BSA is 91.2%. Moreover, the membrane flux recovery rate after cleaning with deionized water was 90.6%. This new type of separation membrane prepared with green materials holds broad application potential in water purification and wastewater treatment.
RESUMEN
Polyvinyl chloride (PVC) is the world's third-most widely produced plastic polymer. Directly transforming PVC to carbonaceous materials for CO2 capture provides an environmentally friendly and attractive strategy to recycle plastics. In this work, a simple and effective method was developed to prepare PVC-derived carbon spheres. In this method, the classical "spheroidization" process shaped the original PVC powders into millimeter spheres, and a special dehalogenation and cross-linking process in the presence of a phase-transfer catalyst transferred the thermoplasticity of the PVC-spheres into thermosetting, which stabilized the shape. Furthermore, by rationally adjusting the activation conditions, the porous structure of the carbon spheres was well optimized. With a specific surface area up to 1738â m2 g-1 and the developed microporous structure, the as-prepared carbon spheres showed not only excellent performance in pure CO2 adsorption (8.93â mmol g-1 , 39.3â wt% at 0 °C and 5.47â mmol g-1 , 24.1â wt% at 25 °C), but also outstanding adsorption capacity and recyclability in low-concentration CO2 capture, even superior to conventional molecular sieves.
RESUMEN
The lack of safe, efficient, and economical hydrogen storage technologies is a hindrance to the realization of the hydrogen economy. Reported herein is a reversible formate-based carbon-neutral hydrogen storage system that is established over a novel catalyst comprising palladium nanoparticles supported on nitrogen-doped mesoporous carbon. The support was fabricated by a hard template method and nitridated under a flow of ammonia. Detailed analyses demonstrate that this bicarbonate/formate redox equilibrium is promoted by the cooperative role of the doped nitrogen functionalities and the well-dispersed, electron-enriched palladium nanoparticles.
Asunto(s)
Carbono/química , Formiatos/química , Hidrógeno/química , Nitrógeno/química , Paladio/química , Catálisis , Modelos Moleculares , Conformación Molecular , Oxidación-Reducción , PorosidadRESUMEN
Glutathione (GSH) plays a critical role in plant growth, development and responses to stress. However, the mechanism by which GSH regulates tolerance to cadmium (Cd) stress still remains unclear. Here we show that inhibition of GSH biosynthesis by buthionine sulfoximine (BSO) aggravated Cd toxicity by increasing accumulation of reactive oxygen species (ROS) and reducing contents of nitric oxide (NO) and S-nitrosothiol (SNO) in tomato roots. In contrast, exogenous GSH alleviated Cd toxicity by substantially minimizing ROS accumulation and increasing contents of NO and SNO, and activities of antioxidant enzymes that eventually reduced oxidative stress. GSH-induced enhancement in Cd tolerance was closely associated with the upregulation of transcripts of several transcription factors such as ETHYLENE RESPONSIVE TRANSCRIPTION FACTOR 1 (ERF1), ERF2, MYB1 TRANSCRIPTION FACTOR- AIM1 and R2R3-MYB TRANSCRIPTION FACTOR- AN2, and some stress response genes. In addition, GSH modulated the cellular redox balance through maintaining increased GSH: GSSG and AsA: DHA ratios, and also increased phytochelatins contents. Nonetheless, GSH-induced alleviation of Cd phytotoxicity was also associated with increased sequestration of Cd into cell walls and vacuoles but not with Cd accumulation. Under Cd stress, while treatment with BSO slightly decreased vacuolar fraction of Cd, combined treatment with BSO and GSH noticeably increased that fraction. Our results suggest that GSH increases tomato tolerance to Cd stress not only by promoting the chelation and sequestration of Cd but also by stimulating NO, SNO and the antioxidant system through a redox-dependent mechanism.