Transcriptome Analysis of Tryptophan-Induced Resistance against Potato Common Scab

Potato common scab (CS) is a worldwide soil-borne disease that severely reduces tuber quality and market value. We observed that foliar application of tryptophan (Trp) could induce resistance against CS. However, the mechanism of Trp as an inducer to trigger host immune responses is still unclear. To facilitate dissecting the molecular mechanisms, the transcriptome of foliar application of Trp and water (control, C) was compared under Streptomyces scabies (S) inoculation and uninoculation. Results showed that 4867 differentially expressed genes (DEGs) were identified under S. scabies uninoculation (C-vs-Trp) and 2069 DEGs were identified under S. scabies inoculation (S-vs-S+Trp). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that Trp induced resistance related to the metabolic process, response to stimulus, and biological regulation. As phytohormone metabolic pathways related to inducing resistance, the expression patterns of candidate genes involved in salicylic acid (SA) and jasmonic acid/ethylene (JA/ET) pathways were analyzed using qRT-PCR. Their expression patterns showed that the systemic acquired resistance (SAR) and induced systemic resistance (ISR) pathways could be co-induced by Trp under S. scabies uninoculation. However, the SAR pathway was induced by Trp under S. scabies inoculation. This study will provide insights into Trp-induced resistance mechanisms of potato for controlling CS, and extend the application methods of Trp as a plant resistance inducer in a way that is cheap, safe, and environmentally friendly

iTRAQ-Based Proteomics Analysis of Response to Solanum tuberosum Leaves Treated with the Plant Phytotoxin Thaxtomin A

Thaxtomin A (TA) is a phytotoxin secreted by Streptomyces scabies that causes common scab in potatoes. However, the mechanism of potato proteomic changes in response to TA is barely known. In this study, the proteomic changes in potato leaves treated with TA were determined using the Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) technique. A total of 693 proteins were considered as differentially expressed proteins (DEPs) following a comparison of leaves treated with TA and sterile water (as a control). Among the identified DEPs, 460 and 233 were upregulated and downregulated, respectively. Based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, many DEPs were found to be involved in defense and stress responses. Most DEPs were grouped in carbohydrate metabolism, amino acid metabolism, energy metabolism, and secondary metabolism including oxidation–reduction process, response to stress, plant–pathogen interaction, and plant hormone signal transduction. In this study, we analyzed the changes in proteins to elucidate the mechanism of potato response to TA, and we provided a molecular basis to further study the interaction between plant and TA. These results also offer the option for potato breeding through analysis of the resistant common scab

Enhancing Sugarcane Growth and Improving Soil Quality by Using a Network-Structured Fertilizer Synergist

High usage and low efficiency of fertilizers not only restrict sugarcane production but also destroy the soil environment in China. To solve this problem, a network-structured nanocomposite as a fertilizer synergist (FS) was prepared based on attapulgite (ATP) and polyglutamic acid (PGA). Field demonstrations were conducted from 2020 to 2021. Leaching tests and characterization were used to evaluate the ability of the network structure to control nutrient loss. The effects of FS on sugarcane growth and field soil quality were also investigated. The results showed FS could effectively reduce nitrogen loss by 20.30% and decrease fertilizer usage by at least 20%. Compared to fertilizer with the same nutrition, fertilizer with FS could enhance sugarcane yield and brix by 20.79% and 0.58 percentage points, respectively. Additionally, FS improved the soil physicochemical properties, including reducing the soil bulk density and increasing the contents of nitrogen, phosphorus, potassium, and organic matter. FS also altered the diversity of the bacteria and improved the bacterial richness. Our study shows this FS has a good ability to control nutrient loss, advance sugarcane agronomic traits, and improve soil quality. This work offers an option for the sustainable development of sugarcane through the novel FS

Clarifying the Controversial Catalytic Performance of Co(OH)₂ and Co₃O₄ for Oxygen Reduction/Evolution Reactions toward Efficient Zn–Air Batteries

Cobalt-based nanomaterials have been widely studied as catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) due to their remarkable bifunctional catalytic activity, low cost, and easy availability. However, controversial results concerning OER/ORR performance exist between different types of cobalt-based catalysts, especially for Co­(OH)₂ and Co₃O₄. To address this issue, we develop a facile electrochemical deposition method to grow Co­(OH)₂ directly on the skeleton of carbon cloth, and further Co₃O₄ was obtained by post thermal treatment. The entire synthesis strategy removes the use of any binders and also avoids the additional preparation process (e.g., transfer and slurry coating) of final electrodes. This leads to a true comparison of the ORR/OER catalytic performance between Co­(OH)₂ and Co₃O₄, eliminating uncertainties arising from the electrode preparation procedures. The surface morphologies, microstructures, and electrochemical behaviors of prepared Co­(OH)₂ and Co₃O₄ catalysts were systemically investigated by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and electrochemical characterization methods. The results revealed that the electrochemically deposited Co­(OH)₂ was in the form of vertically aligned nanosheets with average thickness of about 4.5 nm. After the thermal treatment in an air atmosphere, Co­(OH)₂ nanosheets were converted into mesoporous Co₃O₄ nanosheets with remarkably increased electrochemical active surface area (ECSA). Although the ORR/OER activity normalized by the geometric surface area of mesoporous Co₃O₄ nanosheets is higher than that of Co­(OH)₂ nanosheets, the performance normalized by the ECSA of the former is lower than that of the latter. Considering the superior apparent overall activity and durability, the Co₃O₄ catalyst has been further evaluated by integrating it into a Zn–air battery prototype. The Co₃O₄ nanosheets <i>in situ</i> supported on carbon cloth cathode enable the assembled Zn–air cells with large peak power density of 106.6 mW cm^–2, low charge and discharge overpotentials (0.67 V), high discharge rate capability (1.18 V at 20 mA cm^–2), and long cycling stability (400 cycles), which are comparable or even superior to the mixture of state-of-the-art Pt/C and RuO₂ cathode

Fabrication of a High-Performance Fertilizer To Control the Loss of Water and Nutrient Using Micro/Nano Networks

Nitrogen fertilizer tends to migrate into the environment through runoff, leaching and volatilization, causing severe environmental pollution. In this work, a high-performance water and nutrient loss control fertilizer (WNLCF) was developed by adding a high-energy electron beam (HEEB) dispersed attapulgite (HA)–sodium polyacrylate (P)–polyacrylamide (M) complex to traditional fertilizer. Therein, HA-P-M was used as the water and nutrient loss control agent (WNLCA), which could self-assemble to form three-dimensional (3D) micro/nano networks in aqueous phase. Thus, water and nutrient could be effectively combined and held in the networks which could be then retained in the soil via the filtering effect of soil, resulting in low loss of water and nutrient. Pot experiments of ¹⁵N labeled fertilizer indicated that WNLCF could effectively improve the amounts of fertilizer nutrients in the stem of corn and facilitate the growth of corn. Therefore, this work provides a promising approach to enhance the utilization efficiency of water and nutrient, and lower the pollution risk of fertilizer

Anomalous Interfacial Lithium Storage in Graphene/TiO₂ for Lithium Ion Batteries

Graphene/metal-oxide nanocomposites have been widely studied as anode materials for lithium ion batteries and exhibit much higher lithium storage capacity beyond their theoretical capacity through mechanisms that are still poorly understood. In this research, we present a comprehensive understanding in microscale of the discharge process of graphene/TiO₂ containing surface, bulk, and interfacial lithium storage based on the first-principles total energy calculations. It is revealed that interfacial oxygen atoms play an important role on the interfacial lithium storage. The additional capacity originating from surface and interfacial lithium storage via an electrostatic capacitive mechanism contributes significantly to the electrode capacity. The research demonstrates that for nanocomposites used in energy storage materials, electrode and capacitor behavior could be optimized to develop high-performance electrode materials with the balance of storage capacity and rate

A Facile Approach To Remediate the Microenvironment of Saline–Alkali Soil

A facile approach to remediate the microenvironment of saline–alkali soil (SS) was developed using a novel fertilizer named saline–alkali soil remediating fertilizer (SSRF). SSRF was obtained by adding a nanocomposite as the saline–alkali soil remediating agent (SSRA) made up of attapulgite (ATP), phosphogypsum (PG), sodium polyacrylate (SP), and weathered coal (WC) to a traditional fertilizer (TF). SSRF could form micro/nanonetworks in SS and display a high retaining capacity on water and fertilizer nutrients because of the hydrogen bonds between SSRA and water molecules, urea, or NH₄Cl. In addition, SSRF could effectively reduce the salinity and alkalinity in SS through ion exchange, deactivation, and pH adjusting. Thus, SSRF could significantly improve the microenvironment of SS, which could facilitate the growth of crops and increase the saline–alkaline tolerance of crops

Single-Atomic Ruthenium Catalytic Sites on Nitrogen-Doped Graphene for Oxygen Reduction Reaction in Acidic Medium.

The cathodic oxygen reduction reaction (ORR) is essential in the electrochemical energy conversion of fuel cells. Here, through the NH3 atmosphere annealing of a graphene oxide (GO) precursor containing trace amounts of Ru, we have synthesized atomically dispersed Ru on nitrogen-doped graphene that performs as an electrocatalyst for the ORR in acidic medium. The Ru/nitrogen-doped GO catalyst exhibits excellent four-electron ORR activity, offering onset and half-wave potentials of 0.89 and 0.75 V, respectively, vs a reversible hydrogen electrode (RHE) in 0.1 M HClO4, together with better durability and tolerance toward methanol and carbon monoxide poisoning than seen in commercial Pt/C catalysts. X-ray adsorption fine structure analysis and aberration-corrected high-angle annular dark-field scanning transmission electron microscopy are performed and indicate that the chemical structure of Ru is predominantly composed of isolated Ru atoms coordinated with nitrogen atoms on the graphene substrate. Furthermore, a density function theory study of the ORR mechanism suggests that a Ru-oxo-N4 structure appears to be responsible for the ORR catalytic activity in the acidic medium. These findings provide a route for the design of efficient ORR single-atom catalysts