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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.

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.

Fertilizer application to arable soils could be effective for soil nutrients. However, there are many negative effects in croplands with long-term chemical fertilizer application. Whether eco-friendly fertilizer addition could enhance soil quality and soil microbial activity has been investigated before, however, how top- and rhizosphere soil bacterial communities respond to their short-term effects is not well known. Here, we used Illumina MiSeq sequencing to determine the changes of bacterial community structure in both topsoil and rhizoshpere after one month of the addition of three different eco-friendly fertilizers&mdash, biochar (B), microbial fertilizer (MF), fertilizer synergist (FS) and selected soil base fertilizer (CK) as a control, in an irrigated agroecosystem of cabbage crop (Brassica oleracea L. var. capitata L.). The results show that three different eco-friendly fertilizers significantly enhanced cabbage growth. The Shannon and Ace indexes of the bacterial community significantly decreased under the FS treatment in both soils, but the total abundance of bacteria was maximal under the FS treatment in the topsoil and the MF treatment in the rhizosphere. The addition of the three fertilizers led to significant differences in the relative abundance of bacteria community at the phylum level, such as Proteobacteria, Acidobacteria, Rokubacteria and Planctomycetes in the topsoil, and Chloroflexi, Actinobacteria, Firmicutes and Rokubacteria in the rhizosphere. The same phylum showed the inconsistent changes under different fertilizer treatments in both topsoil and rhizosphere. The dominant genera, i.e., Nitrosospira and Massilia in the topsoil, and Flavobacterium, Nitrosospira and Pseudomonas in the rhizosphere, were much higher under the FS treatment than others. Redundancy analysis showed that total nitrogen and available phosphorus were the key factors that shaped the bacterial community in this ecosystem. These results highlighted that the short-term addition of eco-friendly fertilizer had an improvement effect on the quality of both topsoil and rhizosphere in croplands with long-term chemical fertilizer application.

Most potato tubers were used as seeds and sprouted relatively slowly in soil, greatly influencing potato production. To solve this problem, an amphiphilic nanocomposite was fabricated by loading hydrophobic silica (H-SiO2) in hydrophilic attapulgite nest-like and used as a nano presprouting agent (NPA). This technology could conveniently adjust the occupation area ratio of water and air (OARWA) on the potato surface. NPA could endow potatoes with an appropriate OARWA and, thus, effectively accelerate sprouting. Additionally, NPA greatly decreased soil bulk density, facilitated earthworm growth, promoted potato growth, and increased the yield by 14.1%. Besides, NPA did not pass through the potato skin and mainly existed on the surface of potatoes. Importantly, NPA showed tiny influence on the viability of fish and nematodes, demonstrating good biosafety. Therefore, this work provides a promising presprouting approach for potatoes, which may have a potential application prospect in ensuring food supply.

Urea tends to be hydrolyzed by urease and then migrate into the environment, which results in a low utilization efficiency and severe environmental contamination. To solve this problem, a network-structured nanocomposite (sodium humate-attapulgite-polyacrylamide) was fabricated and used as an excellent fertilizer synergist (FS) that could effectively inhibit the hydrolysis, reduce the loss, and enhance the utilization efficiency of nitrogen. Additionally, the FS exerted significant positive effects on the expression of several nitrogen-uptake-related genes, ion flux in maize roots, the growth of crops, and the organic matter in soil. The FS could modify the microbial community in the soil and increase the number of bacteria involved in nitrogen metabolism, organic matter degradation, the iron cycle, and photosynthesis. Importantly, this technology displayed a high biosafety and has a great potential to reduce nonpoint agricultural pollution. Therefore, this work provides a promising approach to manage nitrogen and to promote the sustainable development of agriculture and the environment.

Traditional pesticides (TP) often do not adhere tightly to crop foliage. They can easily enter the surrounding environment through precipitation and volatilization. This can result in the pollution of the surrounding soil, water, and air. To reduce pesticide pollution, we developed a loss-control pesticide (LCP) by adding attapulgite with a nano networks structure fabricated using high energy electron beam (HEEB) irradiation and hydrothermal treatment to TP. HEEB irradiation effectively dispersed originally aggregated attapulgite through modified thermal, charge, and physical effects. Hydrothermal treatment further enhanced the dispersion of attapulgite to form nano porous networks via thermal and wet expansion effects, which are beneficial for pesticide binding. An LCP has improved retention on crop leaf surfaces. It has a higher adhesion capacity, reduced leaching and volatilization, and extended residual activity compared with the TP formulation. The treatment increases the residual activity of pesticides on crop foliage and decreases environmental pollution.

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 utilizati...

Foliar nitrogen fertilizer (FNF) unabsorbed by crops leaves eventually discharges into environment through rainwater washing, leaching and volatilization, causing severe pollution to water, soil and air. Therefore, improving the adhesion capacity of FNF is sorely needed. This work developed a loss-control foliar nitrogen fertilizer (LCFNF) by adding a complex, as a loss control agent (LCA), including attapulgite (ATP) irradiated by high-energy electron beam (HEEB), and straw ash-based biochar and biosilica (BCS) to traditional FNF. LCA possesses a porous micro/nano networks structure and thus could bind a large amount of nitrogen to form fertilizer-ATP-BCS system, which could be then retained by the rough surface of crop leaves. As a result, LCFNF displayed higher adhesion performance on crop leaves, lower loss amount and thus higher utilization efficiency compared with FNF. This work provides a novel and promising approach to control the loss of traditional FNF and ultimately lower the environment pollut...

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.

Acetyl-CoA carboxylase (ACC) catalyzes the first step of fatty acid synthesis. In most bacteria, ACC is composed of four subunits encoded by accA, accB, accC, and accD. Of them, accA encodes acetyl-CoA carboxyltransferase alpha-subunit. Our prior work on proteomics of Alkalimonas amylolytica N10 showed that the expression of the Aa-accA has a remarkable response to salt and alkali stress. This research aimed to find out the Aa-accA gene contributing to salt and alkali tolerance.The Aa-accA was amplified by PCR from A. amylolytica N10 and expressed in E. coli K12 host. The effects of Aa-accA expression on the growth of transgenic strains were examined under different NaCl concentration and pH conditions. Transgenic tobacco BY-2 cells harboring Aa-accA were also generated via Agrobacterium-mediated transformation. The viability of BY-2 cells was determined with FDA staining method after salt and alkali shock.The Aa-accA gene product has 318 amino acids and is homologous to the carboxyl transferase domain of acyl-CoA carboxylases. It showed 76% identity with AccA (acetyl-CoA carboxylase carboxyltransferase subunit alpha) from E. coli. Compared to the wild-type strains, transgenic E. coli K12 strain containing Aa-accA showed remarkable growth superiority when grown in increased NaCl concentrations and pH levels. The final cell density of the transgenic strains was 2.6 and 3.5 times higher than that of the control type when they were cultivated in LB medium containing 6% (W/V) NaCl and at pH 9, respectively. Complementary expression of Aa-accA in an accA-depletion E. coli can recover the tolerance of K12 delta accA to salt and alkali stresses to some extent. Similar to the transgenic E. coli, transgenic tobacco BY-2 cells showed higher percentages of viability compared to the wild BY-2 cells under the salt or alkali stress condition.We found that Aa-accA from A. amylolytica N10 overexpression enhances the tolerance of both transgenic E. coli and tobacco BY-2 cells to NaCl and alkali stresses.