Burkholderia ambifaria H8 as an effective biocontrol strain against maize stalk rot via producing volatile dimethyl disulfide.

BACKGROUND: Maize stalk rot (MSR) caused by Fusarium graminearum is the primary factor contributing to the reduction in maize yield and quality. However, this soil-borne disease presents a significant challenge for sustainable control through field management and chemical agents. The screening of novel biocontrol agents can aid in developing innovative and successful strategies for MSR control. RESULTS: A total of 407 strains of bacteria were isolated from the rhizosphere soil of a resistant maize inbred line. One strain exhibited significant antagonistic activity in plate and pot experiments, and was identified as Burkholderia ambifaria H8. The strain could significantly inhibit the mycelial growth and spore germination of F. graminearum, induce resistance to stalk rot, and promote plant growth. The volatile compounds produced by strain H8 and its secondary metabolites in the sterile fermentation broth exhibited antagonistic activity. The primary volatile compound produced by strain H8 was identified as dimethyl disulfide (DMDS) using gas chromatography tandem mass spectrometry. Through in vitro antagonistic activity assays and microscopic observation, it was confirmed that DMDS was capable of inhibiting mycelial growth and disrupting the mycelial structure of F. graminearum, suggesting it may be the major active compound for strain H8. The transcriptome data of F. graminearum further indicated that strain H8 and its volatile compounds could alter pathogenic fungi metabolism, influence the related metabolic pathways, and potentially induce cell apoptosis within F. graminearum. CONCLUSION: Our results showed that B. ambifaria H8 was capable of producing the volatile substance dimethyl disulfide, which influenced the synthesis and permeability of cell membranes in pathogens. Thus, B. ambifaria H8 was found to be a promising biological control agent against MSR. © 2024 Society of Chemical Industry.

First Report of Yellow Leaf Spots on Maize Caused by Colletotrichum siamense in Yunnan Province, China.

The southwest maize planting area is the third largest maize-producing region in China, including the entire provinces of Sichuan, Yunnan and Guizhou, parts of Guangxi and Hunan provinces. In June 2022, yellow leaf spot symptoms were observed commonly on maize in southern Yunnan province, including Pu'er City, Xishuangbanna Dai autonomous prefecture and Honghe Hani & Yi autonomous prefecture. The disease incidence on maize in Pu'er ranged from 10% to 20% from June to August. The initial symptoms appeared as needle-like spots scattered on the leaf surface with obvious yellow haloes, with a diameter ranging from 0.2 to 2 mm and were quite similar to maize Curvularia leaf spot. But the lesion size did not expand significantly and without reddish or dark brown margins. In July 2023, 30 diseased leaves were collected in Pu'er City, Yunnan Province. Leaf tissues (3×3 mm) were cut from the infected margins, surface disinfested with 75% ethanol for 30 s, 2% sodium hypochlorite for 2 min, and rinsed three times with sterile water, then placed on PDA at 25℃. Forty-eight isolates with the morphological characteristics of Colletotrichum ssp. were obtained by single-spore isolations (isolation frequency 42.5%). The fungal colonies on PDA were dense with white mycelia on the edges, and yellowish-white on the reverse side. The conidia were transparent, cylindrical, smooth-walled, and 6.8 to 17.5 × 3.8 to 6.5 µm. Two isolates (YNH-1 and YNH-2) were used for DNA extraction. The ribosomal internal transcribed spacer (ITS), actin (ACT), calmodulin (CAL), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and ß-tubulin 2 (TUB2) regions were amplified by PCR. The PCR primers in this study were as described previously (Weir et al. 2012). The sequences of both isolates were 100% identical, and all sequences showed >98% identity with Colletotrichum siamense in the GenBank. The sequences were deposited in GenBank (ITS, PP237394; ACT, PP265410; CAL, PP265411; GAPDH, PP265412; TUB2, PP265413). A phylogenetic tree was constructed by MEGA_v. 11.0.13 with the Maximum Likelihood (ML) method. The isolate YNH-1 and YNH-2 clustered with C. siamense DAR 76934 (97% bootstrap support) in the same branch. Pathogenicity tests were performed on the susceptible maize variety B73. Twelve healthy maize seedlings were inoculated with a conidial suspension (1×106 conidia/ml) of isolate YNH-1. All the seedlings were kept in an incubator at 26℃, with a 90% humidity and a 12 h light/dark cycle. After 5 days, yellow spots appeared on the leaves of the plants. The symptoms on inoculated leaves were similar to those observed in the field after 10 days, whereas no symptoms appeared in the control. The pathogen C. siamensis was re-isolated from the infected leaves, which fulfilled the Koch's postulates. C. siamense can cause leaf diseases on a wide range of hosts. It has been reported causing anthracnose on tea (Camellia sinensis) (Wang et al. 2016) and wax apple (Syzygium samarangense) (Yao et al. 2023) in Yunnan Province, China. To our knowledge, this is the first report of C. siamense causing yellow leaf spots on maize in China as well as a new host record for C. siamense causing leaf disease. However, how C. siamense spreads among different host plants in the region is still unknown. This study provides important information for epidemiological study and comprehensive management of yellow leaf spot on maize.

Direct Observation of Z-Scheme Route in Cu31 S16 /Znx Cd1-x S Heteronanoplates for Highly Efficient Photocatalytic Hydrogen Evolution.

Although photocatalytic hydrogen production from water holds great potential as a renewable and sustainable energy alternative, the practical application of the technology demands cost-effective, simple photocatalytic systems with high efficiency in hydrogen evolution reaction (HER). Herein, the synthesis and characterization of Cu31 S16 /Znx Cd1-x S heterostructured nanoplates (Cu31 S16 /ZnCdS HNPs) as a high photocatalytic system are reported. The cost-effective, hierarchical structures are easily prepared using the Cu31 S16 NPs as the seed by the epitaxial growth of the ZnCdS nanocrystals (NCs). The Cu31 S16 /ZnCdS without the noble metal cocatalyst exhibits a high HER rate of 61.7 mmol g-1  h-1 , which is 8,014 and 17 times higher than that of Cu31 S16 and ZnCdS, respectively, under visible light irradiation. The apparent quantum yield (AQY) of Cu31 S16 /ZnCdS reaches 67.9% at 400 nm with the highest value so far in the reported ZnCdS-based photocatalysts. The excellent activity and stability of the Cu31 S16 /ZnCdS are attributed to the formation of a strong internal electric field (IEF) and the Z-scheme pathway. The comprehensive experiments and theoretical calculations provide the direct evidences of the Z-scheme route. This work may offer a way for the design and development of efficient photocatalysts to achieve solar-to-chemical energy conversion at a practically useful level.

Controllable CVD Growth of 2D Cr5Te8 Nanosheets with Thickness-Dependent Magnetic Domains.

As a unique 2D magnetic material with self-intercalated structure, Cr5Te8 exhibits many intriguing magnetic properties. While its ferromagnetism of Cr5Te8 has been previously reported, the research on its magnetic domain remains unexplored. Herein, we have successfully fabricated 2D Cr5Te8 nanosheets with controlled thickness and lateral size by chemical vapor deposition (CVD). Then magnetic property measurement system revealed Cr5Te8 nanosheets exhibiting intense out-of-plane ferromagnetism with a Curie temperature (TC) of 176 K. Significantly, we reported for the first time two magnetic domains: magnetic bubbles and thickness-dependent maze-like magnetic domains in our Cr5Te8 nanosheets by cryogenic magnetic force microscopy (MFM). The domain width of the maze-like magnetic domains increases rapidly with decreasing sample thickness; meanwhile, the domain contrast decreases. This indicates the dominant role of ferromagnetism shifts from dipolar interactions to magnetic anisotropy. Our research not only establishes a pathway for the controllable growth of 2D magnetic materials but also points toward novel avenues for regulating magnetic phases and methodically tuning domain characteristics.

Genomic survey of NPF and NRT2 transporter gene families in five inbred maize lines and their responses to pathogens infection.

Besides manipulating nitrate uptake and allocation, nitrate transporters (NRTs) are also known to play crucial roles in pathogen defense and stress response. By blasting with the model NRT genes of poplar and Arabidopsis, a total of 408 gene members were identified from 5 maize inbred lines in which the number of NRTs ranged from 72 to 88. Phylogenetic analysis showed that the NRT genes of maize were classified into NRT1/PTR (NPF), NRT2 and NRT3 subfamilies, respectively. Marked divergence of the duplication patterns of NRT genes were identified, which may be a new basis for classification and identification of maize varieties. In terms of biotic stress, NRT2.5A showed an enhanced expression during the pathogen infection of Colletotrichum graminicola, while NRT1c4C was down-regulated, suggesting that maize NRT transporters may have both positive and negative roles in the disease resistance response. This work will promote the further studies of NRT gene families in maize, as well as be beneficial for further understanding of their potential roles in plant-pathogen interactions.

Synthesis, phloem mobility and induced plant resistance of synthetic salicylic acid amino acid or glucose conjugates.

BACKGROUND: The growing demand for food, combined with a strong social expectation for a diet produced with fewer conventional agrochemical inputs, has led to the development of new alternatives in plant protection worldwide. Among different possibilities, the stimulation of the plant innate immune system by chemicals represents a novel and promising way. The vectorization strategy of an active ingredient that we previously developed with fungicides can potentially extend to salicylic acid (SA) or its halogenated analogues. RESULTS: Using the click chemistry method, six new conjugates combining SA or two mono- or di-halogenated analogues with L-glutamic acid or ß-D-glucose via a 1,2,3-triazole nucleus have been synthesized. Conjugate 8a, which is derived from SA and glutamic acid, showed high phloem mobility in the Ricinus model, similar to that of SA alone despite a much higher steric hindrance. In vivo bioassays of the six conjugates against two maize pathogenic fungi Bipolaris maydis and Fusarium graminearum revealed that, unlike SA, the amino acid conjugate 8a with good phloem mobility exerted a protective effect not only locally at the application site, but also in distant stem tissues after foliar application. Moreover, compounds 8a and 8b induced up-regulation of both defense-related genes ZmNPR1 and ZmPR1 similar to their parent compounds upon challenge inoculation with B. maydis. CONCLUSION: The vectorization of salicylic acid or its halogenated derivatives by coupling them with an α-amino acid can be a promising strategy to stimulate SA-mediated plant defenses responses against pathogens outside the application site. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Glycosylphosphatidylinositol Anchor Biosynthesis Pathway-Related Protein GPI7 Is Required for the Vegetative Growth and Pathogenicity of Colletotrichum graminicola.

Glycosylphosphatidylinositol (GPI) anchoring is a common post-translational modification in eukaryotic cells and has been demonstrated to have a wide range of biological functions, such as signal transduction, cellular adhesion, protein transport, immune response, and maintaining cell wall integrity. More than 25 proteins have been proven to participate in the GPI anchor synthesis pathway which occurs in the cytoplasmic and the luminal face of the ER membrane. However, the essential proteins of the GPI anchor synthesis pathway are still less characterized in maize pathogen Colletotrichum graminicola. In the present study, we analyzed the biological function of the GPI anchor synthesis pathway-related gene, CgGPI7, that encodes an ethanolamine phosphate transferase, which is localized in ER. The vegetative growth and conidia development of the ΔCgGPI7 mutant was significantly impaired in C. graminicola. and qRT-PCR results showed that the transcriptional level of CgGPI7 was specifically induced in the initial infection stage and that the pathogenicity of ΔCgGPI7 mutant was also significantly decreased compared with the wild type. Furthermore, the ΔCgGPI7 mutant displayed more sensitivity to cell wall stresses, suggesting that CgGPI7 may play a role in the cell wall integrity of C. graminicola. Cell wall synthesis-associated genes were also quantified in the ΔCgGPI7 mutant, and the results showed that chitin and ß-1,3-glucans synthesis genes were significantly up-regulated in ΔCgGPI7 mutants. Our results suggested that CgGPI7 is required for vegetative growth and pathogenicity and might depend on the cell wall integrity of C. graminicola.

Plant Peroxisome-Targeting Effector MoPtep1 Is Required for the Virulence of Magnaporthe oryzae.

Rice blast caused by Magnaporthe oryzae is one of the most serious fungous diseases in rice. In the past decades, studies have reported that numerous M. oryzae effectors were secreted into plant cells to facilitate inoculation. Effectors target host proteins to assist the virulence of pathogens via the localization of specific organelles, such as the nucleus, endoplasmic reticulum, chloroplast, etc. However, studies on the pathogenesis of peroxisome-targeting effectors are still limited. In our previous study, we analyzed the subcellular localization of candidate effectors from M. oryzae using the agrobacterium-mediated transient expression system in tobacco and found that MoPtep1 (peroxisomes-targeted effector protein 1) localized in plant peroxisomes. Here, we proved that MoPtep1 was induced in the early stage of the M. oryzae infection and positively regulated the pathogenicity, while it did not affect the vegetative growth of mycelia. Subcellular localization results showed that MoPtep1 was localized in the plant peroxisomes with a signal peptide and a cupredoxin domain. Sequence analysis indicated that the homologous protein of MoPtep1 in plant-pathogenic fungi was evolutionarily conserved. Furthermore, MoPtep1 could suppress INF1-induced cell death in tobacco, and the targeting host proteins were identified using the Y2H system. Our results suggested that MoPtep1 is an important pathogenic effector in rice blast.

Glycosyltransferase FvCpsA Regulates Fumonisin Biosynthesis and Virulence in Fusarium verticillioides.

Fusarium verticillioides is the major maize pathogen associated with ear rot and stalk rot worldwide. Fumonisin B1 (FB1) produced by F. verticillioides, poses a serious threat to human and animal health. However, our understanding of FB1 synthesis and virulence mechanism in this fungus is still very limited. Glycosylation catalyzed by glycosyltransferases (GTs) has been identified as contributing to fungal infection and secondary metabolism synthesis. In this study, a family 2 glycosyltransferase, FvCpsA, was identified and characterized in F. verticillioides. ΔFvcpsA exhibited significant defects in vegetative growth. Moreover, ΔFvcpsA also increased resistance to osmotic and cell wall stress agents. In addition, expression levels of FUM genes involved in FB1 production were greatly up-regulated in ΔFvcpsA. HPLC (high performance liquid chromatography) analysis revealed that ΔFvcpsA significantly increased FB1 production. Interestingly, we found that the deletion of FvCPSA showed penetration defects on cellophane membrane, and thus led to obvious defects in pathogenicity. Characterization of FvCpsA domain experiments showed that conserved DXD and QXXRW domains were vital for the biological functions of FvCpsA. Taken together, our results indicate that FvCpsA is critical for fungal growth, FB1 biosynthesis and virulence in F. verticillioides.

Genomic Sequence Resource of Kabatiella zeae, the Causative Pathogen of Corn Eyespot Disease.

Kabatiella zeae is the causative pathogen of corn eyespot disease, which is an important leaf disease that damages corn (Zea mays L.) worldwide. In this study, we provided an annotated draft of the assembled genome of the K. zeae field strain KZ1 through PacBio and Illumina sequencing. The assembled KZ1 genome size is 23,602,820 bp, and its GC content is 50.71%. The completeness of the assembled genome is 97.6% in this study. The assembly obtained in this study has 94 contigs and the length of N50 is 720,243 bp. This study is the first report of the K. zeae genome, which contributes to further research on the genetic variation and pathogenic mechanism of this important fungal pathogen.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Self-Powered Intelligent Human-Machine Interaction for Handwriting Recognition.

Handwritten signatures widely exist in our daily lives. The main challenge of signal recognition on handwriting is in the development of approaches to obtain information effectively. External mechanical signals can be easily detected by triboelectric nanogenerators which can provide immediate opportunities for building new types of active sensors capable of recording handwritten signals. In this work, we report an intelligent human-machine interaction interface based on a triboelectric nanogenerator. Using the horizontal-vertical symmetrical electrode array, the handwritten triboelectric signal can be recorded without external energy supply. Combined with supervised machine learning methods, it can successfully recognize handwritten English letters, Chinese characters, and Arabic numerals. The principal component analysis algorithm preprocesses the triboelectric signal data to reduce the complexity of the neural network in the machine learning process. Further, it can realize the anticounterfeiting recognition of writing habits by controlling the samples input to the neural network. The results show that the intelligent human-computer interaction interface has broad application prospects in signature security and human-computer interaction.

Genome Sequence Resource for Nigrospora oryzae, an Important Pathogenic Fungus Threatening Crop Production.

Nigrospora oryzae is an important phytopathogenic fungus with a broad host range. Here, we report an annotated draft of the genome of N. oryzae field strain GZL1 collected from maize assembled from PacBio and Illumina sequencing reads. The assembly we obtained has 15 scaffolds with an N50 length of 4,037,616 bp. The resulting GZL1 draft genome is 43,214,190 bp, with GC content of 58.19%. The completeness of GZL1 genome assembly is 99.30%. This study is the first report of the genome sequence of N. oryzae, which can facilitate future study of the genetic variation and pathogenic mechanism of this important fungal pathogen.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Phloem Delivery of Fludioxonil by Plant Amino Acid Transporter-Mediated Polysuccinimide Nanocarriers for Controlling Fusarium Wilt in Banana.

Fusarium wilt disease poses a serious threat to the global production of bananas. The targeted delivery of fungicides to banana phloem tissues may offer new hope for controlling this hard-to-treat vascular disease. In this study, fludioxonil (FLU)-loaded glycine methyl ester-conjugated polysuccinimide nanoparticles (PGA) were prepared with a loading efficiency (LE) of 27.9%. The obtained nanoparticles (FLU@PGA) exhibited pH-sensitive controlled release, specifically under an alkaline pH in plant phloem. In vivo experiments in potted bananas demonstrated that FLU@PGA can achieve the downward delivery of FLU to banana rhizomes and roots after foliar application, reducing disease severity by 50.4%. The phloem transport studies showed that the phloem loading of FLU@PGA was involved in an active transport mechanism at the organ level (castor bean seedlings). The observation of fluorescein-5-isothiocyanate cadaverine-labeled PGA nanocarriers showed that they could be absorbed by mesophyll cells and loaded into vascular tissues through the symplastic pathway. Furthermore, the interaction of FLU@PGA with the plant amino acid transporter AtLHT1 was observed to enhance transmembrane uptake at the cellular level (Xenopus oocytes). These results suggested that the phloem-targeted delivery of fungicide by transporter-mediated nanocarriers could be a promising new strategy for the management of Fusarium wilt in bananas.

Silver Nanowire-Bacterial Cellulose Composite Fiber-Based Sensor for Highly Sensitive Detection of Pressure and Proximity.

Fiber-based sensors are desirable to provide an immersive experience for users in the human-computer interface. We report a hierarchically porous silver nanowire-bacterial cellulose fiber that can be utilized for sensitive detection of both pressure and proximity of human fingers. The conductive fiber was synthesized via continuous wet-spinning at a speed of 20 m/min, with a diameter of 53 µm, the electrical conductivity of 1.3 × 104 S/cm, a tensile strength of 198 MPa, and elongation strain of 3.0% at break. The fibers were coaxially coated with a 10 µm thick poly(dimethylsiloxane) dielectric elastomer to form the fiber sensor element which is thinner than a human hair. Two of the sensor fibers were laid diagonally, and the capacitance changes between the conductive cores were measured in response to pressure and proximity. In the touch mode, a fiber-based sensor experienced monotonic capacitance increase in the pressure range from 0 to 460 kPa, and a linear response with a high sensitivity of 5.49 kPa-1 was obtained in the low-pressure regime (<0.5 kPa). In touchless mode, the sensor is highly sensitive to objects at a distance of up to 30 cm. Also, the fiber can be easily stitched into garments as comfortable and fashionable sensors to detect heartbeat and vocal pulses. A fiber sensor array is able to serve as a touchless piano to play music and accurately determine the proximity of an object. A 2 × 2 array was further shown for two- and three-dimensional location detection of remote objects.

Evaluating the combined effect of a systemic phenylpyrrole fungicide and the plant growth-promoting rhizobacteria Paraburkholderia phytofirmans (strain PsJN::gfp2x) against the grapevine trunk pathogen Neofusicoccum parvum.

BACKGROUND: A new chemical control strategy for grapevine trunk diseases (GTDs) is to develop site-targeted fungicides to protect grapevine vascular tissues. Due to the complexity of GTDs, the effectiveness of a single method is limited. Investigation of the interactions between chemical and biological agents is an essential requirement for integrated control strategies. The effect of a phloem-mobile derivative of the fungicide fenpiclonil (SM 26) in combined use with the plant growth-promoting rhizobacteria, Paraburkholderia phytofirmans PsJN on the Neofusicoccum parvum strain Bourgogne (NpB) was evaluated. RESULTS: SM 26 was found to be translocated to the shoot apices and roots of grapevines through both xylem and phloem after foliage application. In vitro studies demonstrated that SM 26 exhibited no inhibitory effect on the growth of PsJN and could be largely absorbed into the bacterial cells. In vivo evaluation showed that the combined use of SM 26 and PsJN was the most effective following artificial inoculation of NpB on the stems of rooted Chardonnay and Sauvignon cuttings. Finally, the expression of defence-related genes, including the genes associated with secondary metabolism (ANTS, PAL, STS, Vv17.3), defence proteins (GLUC, PR1, PGIP), redox status (GTS1) and ethylene synthesis (ACC), was found to be strongly upregulated in PsJN + SM 26 cotreated plants compared to non-treated plants (controls), especially for Chardonnay. CONCLUSION: The systemic profungicide SM 26 interacts with the biocontrol agent PsJN to stimulate some plant defence responses, and their combined use may present a potential integrated control strategy against GTDs. © 2020 Society of Chemical Industry.

Synthesis, bioactivities and phloem uptake of dipeptide-chlorantraniliprole derivatives.

Phloem systemicity is a desirable property for insecticides to control sucking insects. However, the development of phloem systemic insecticides is challenging. One possible strategy is to link existed insecticides with endogenous substances so that the resulting conjugates can be transported by specific transporters into the phloem. In this study, novel dipeptide promoieties were introduced into chlorantraniliprole, which is an efficient and broad-spectrum anthranilic diamide insecticide without phloem mobility. Twenty-two new dipeptide-chlorantraniliprole conjugates have been synthesized. Systemic tests showed that all conjugates exhibited phloem mobility in Ricinus communis. In particular, compound 4g with alanyl-alanine dipeptide fragment was able to accumulate in phloem sap (114.49 ± 11.10 µM) in the form of its hydrolysis product 5g. Results of bioassay showed that conjugates 4g and 5g were able to exhibit comparable insecticidal activity against Plutella xylostella L. and Spodoptera exigua compared to its parent compound chlorantraniliprole. This work demonstrated that the dipeptide structures were able to contribute to the improvement of the uptake and phloem mobility of chlorantraniliprole, and two phloem mobile conjugates with satisfactory in vivo insecticidal effect was obtained as new candidates for high-efficient insecticides.

Self-Powered Multifunctional Electronic Skin for a Smart Anti-Counterfeiting Signature System.

Self-powered electronic skin is a promising field for human-machine interfaces to the next generation of intelligent and interactive products due to its capability of including multiple physical parameters for sensing without additional energy supply. This paper reports a novel active multifunctional electronic skin capable of independently detecting contact trajectory, acceleration, velocity, and pressure based on the synchronized triboelectrification and piezoelectric effect. Motion trajectories in the full plane can be identified by using a net-cross electrodes configuration design. Under this electrode special structure design, the motion information such as velocity and acceleration can be accurately obtained by the time difference between the peak values of the triboelectric signal. Real-time detection of dynamic pressure with only two electrodes is achieved by a spacer-grid design and a high quality piezoelectric nanofiber film. By virtue of its high sensitivity and precision, a smart anti-counterfeiting signature system (SASS) can be achieved by this self-powered multifunctional electronic skin with the capability of recognizing the writing habits of people within a 100 ms error for security. It is also a promising candidate in terms of human-machine interaction, cyber security, and so on.

Sulfoxaflor Applied via Drip Irrigation Effectively Controls Cotton Aphid (Aphis gossypii Glover).

Aphis gossypii Glover is a major pest of cotton and can severely affect cotton yield and lint quality. In this study, the efficacy of sulfoxaflor applied via drip irrigation and foliar spray on controlling cotton aphids was evaluated in 2016 and 2017 in Xinjiang, China. The distribution of sulfoxaflor in cotton roots, stems, leaves, and aphids, as well as its effects on two natural enemies of aphids, were also investigated. Results showed that sulfoxaflor applied through drip irrigation mainly concentrated in leaves and provided effective control of cotton aphids for 40 days, compared to 20 days when applied through foliar spray. Furthermore, drip application resulted in much lower sulfoxaflor concentrations in aphids than foliar spray. As a result, ladybird beetle and lacewing populations were higher in drip applied plants than in foliar sprayed plants. Additionally, the cost of drip irrigation was lower than foliar spray as cotton plants are commonly irrigated via drip irrigation in Xinjiang. Our results showed that application of sulfoxaflor through drip irrigation is an effective way of controlling cotton aphids in Xinjiang due to a prolonged control period, safety to two natural enemies, and lower cost of application.

Vectorizing agrochemicals: enhancing bioavailability via carrier-mediated transport.

Systemicity of agrochemicals is an advantageous property for controlling phloem sucking insects, as well as pathogens and pests not accessible to contact products. After the penetration of the cuticle, the plasma membrane constitutes the main barrier to the entry of an agrochemical into the sap flow. The current strategy for developing systemic agrochemicals is to optimize the physicochemical properties of the molecules so that they can cross the plasma membrane by simple diffusion or ion trapping mechanisms. The main problem with current systemic compounds is that they move everywhere within the plant, and this non-controlled mobility results in the contamination of the plant parts consumed by vertebrates and pollinators. To achieve the site-targeted distribution of agrochemicals, a carrier-mediated propesticide strategy is proposed in this review. After conjugating a non-systemic agrochemical with a nutrient (α-amino acids or sugars), the resulting conjugate may be actively transported across the plasma membrane by nutrient-specific carriers. By applying this strategy, non-systemic active ingredients are expected to be delivered into the target organs of young plants, thus avoiding or minimizing subsequent undesirable redistribution. The development of this innovative strategy presents many challenges, but opens up a wide range of exciting possibilities. © 2018 Society of Chemical Industry.