Ectopic enhancer-enhancer interactions as causal forces driving RNA-directed DNA methylation in gene regulatory regions.

Cis-regulatory elements (CREs) are integral to the spatiotemporal and quantitative expression dynamics of target genes, thus directly influencing phenotypic variation and evolution. However, many of these CREs become highly susceptible to transcriptional silencing when in a transgenic state, particularly when organised as tandem repeats. We investigated the mechanism of this phenomenon and found that three of the six selected flower-specific CREs were prone to transcriptional silencing when in a transgenic context. We determined that this silencing was caused by the ectopic expression of non-coding RNAs (ncRNAs), which were processed into 24-nt small interfering RNAs (siRNAs) that drove RNA-directed DNA methylation (RdDM). Detailed analyses revealed that aberrant ncRNA transcription within the AGAMOUS enhancer (AGe) in a transgenic context was significantly enhanced by an adjacent CaMV35S enhancer (35Se). This particular enhancer is known to mis-activate the regulatory activities of various CREs, including the AGe. Furthermore, an insertion of 35Se approximately 3.5 kb upstream of the AGe in its genomic locus also resulted in the ectopic induction of ncRNA/siRNA production and de novo methylation specifically in the AGe, but not other regions, as well as the production of mutant flowers. This confirmed that interactions between the 35Se and AGe can induce RdDM activity in both genomic and transgenic states. These findings highlight a novel epigenetic role for CRE-CRE interactions in plants, shedding light on the underlying forces driving hypermethylation in transgenes, duplicate genes/enhancers, and repetitive transposons, in which interactions between CREs are inevitable.

Vacancy-assisted exposed Sn atoms enhancing NO2 room temperature sensing of SnSe2 nanoflowers.

NO2 is a hazardous gas extremely harmful to the ecosystem and human health, so effective detection of NO2 is critical. SnSe2 is a promising candidate for gas sensors owing to its unique layered configuration that facilitates the diffusion of gas molecules. Here, ultrathin self-assembled nanoflowers F-SnSe2 rich in defects were synthesized by a simple solvothermal method. It exhibits excellent gas sensing performances for NO2 at room temperature (25 °C), with a high gas sensing response of 8.6 for 1 ppm NO2 and a lower detection limit as low as 200 ppb, capable of sensitively detecting ppb-level NO2. DFT calculations revealed that the presence of Se vacancies assists the central Sn atoms to break through the shielding effect of the surface Se atoms and become exposed active sites. The higher reactivity leads to more charge transfer and higher adsorption energy, which strongly promoted the adsorption of NO2. This work verifies the important role of vacancies for the exposed active sites and provides new guidance for defect engineering to modulate the gas sensing performances of SnSe2.

Lateral GeSn p-i-n photodetectors on insulator prepared by the rapid melting growth method.

In this work, GeSn lateral p-i-n photodetectors (PDs) on insulator were fabricated with an active GeSn layer grown by the rapid melting growth (RMG) method. Taking advantages of the defect-free GeSn strips, GeSn PDs with 5.3% Sn content have low dark current and high responsivities, which are about 0.48, 0.47, and 0.24 A/W for wavelengths of 1550, 1630, and 2000 nm, respectively. The radio frequency of the lateral GeSn PDs was also studied and a 3 dB bandwidth of about 3.8 GHz was achieved. These results indicate that the GeSn grown by the rapid melting growth method is capable of fabricating high-performance Si-based optoelectronic devices.

Ce-Ag Active Bimetallic Pairs in Two-Dimensional SnS2 for Enhancing NO2 Sensing.

Developing gas sensors capable of efficiently detecting harmful gases is urgent to protect the human environment. Here, an active Ce-Ag bimetallic pair was innovatively introduced into SnS2, which successfully exhibited excellent NO2 gas sensing performance. 0.8% Ce-SnS2-Ag showed a gas sensing response of 5.18 to 1 ppm of NO2 at a low temperature of 80 °C, with a lower limit of detection as low as 100 ppb. DFT calculations revealed that Ce atoms are substituted into the main lattice of SnS2, which opens up the interlayer spacing and serves as an anchor point to fix the Ag atoms in the interlayer. The Ce-Ag bimetallic pairs successfully modulate the electronic structure of SnS2, which promotes the adsorption and charge transfer between NO2 and Ce-SnS2-Ag and thus achieves such an outstanding gas sensing performance. This work opens an avenue for the rational functional modification of SnS2 with an optimized electronic structure and enhanced gas sensing.

Synthesis and Structure-Activity Analysis of Novel Potential Antifungal Cyclotryptamine Alkaloid Derivatives.

A total of 39 novel cyclotryptamine alkaloid derivatives were prepared from 2-(1H-indol-3-yl) acetonitrile. The prepared compounds were evaluated against six plant pathogen fungi. Bioassay results revealed that most of the compounds displayed higher in vitro antifungal activities than the positive control. Notably, compound b2 displayed the broadest and most effective activity among the tested cyclotryptamine alkaloid derivatives and might be a novel potential leading compound for further development as an antifungal agent.

Debiased Scene Graph Generation for Dual Imbalance Learning.

Scene graph generation (SGG) is one of the hottest topics in computer vision and has attracted many interests since it provides rich semantic information between objects. In practice, the SGG datasets are often dual imbalanced, presented as a large number of backgrounds and rarely few foregrounds, and highly skewed foreground relationships categories (i.e., the long-tailed distribution). How to tackle this dual imbalanced problem is crucial but rarely studied in literature. Existing methods only consider the long-tailed distribution of foregrounds classes and ignore the background-foreground imbalance in SGG, which results in a biased model and prevents it from being applied in the downstream tasks widely. To reduce its side effect and make the contributions of different categories equally, we propose a novel debiased SGG method (named DSDI) by incorporating biased resistance loss and causal intervention tree. We first deeply analyze the potential causes of dual imbalanced problem in SGG. Then, to learn more discriminate representation of the foreground by expanding the foreground features space, the biased resistance loss decouples the background classification from foreground relationship recognition. Meanwhile, a causal graph of content and context is designed to remove the context bias and learn unbiased relationship features via casual intervention tree. Extensive experimental results on two extremely imbalanced datasets: VG150 and VrR-VG, demonstrate our DSDI outperforms other state-of-the-art methods. All our models will be available in https://github.com/zhouhao0515/unbiasedSGG-DSDI.

High abundance of solar wind-derived water in lunar soils from the middle latitude.

Remote sensing data revealed that the presence of water (OH/H2O) on the Moon is latitude-dependent and probably time-of-day variation, suggesting a solar wind (SW)-originated water with a high degassing loss rate on the lunar surface. However, it is unknown whether or not the SW-derived water in lunar soil grains can be preserved beneath the surface. We report ion microprobe analyses of hydrogen abundances, and deuterium/hydrogen ratios of the lunar soil grains returned by the Chang'e-5 mission from a higher latitude than previous missions. Most of the grain rims (topmost ~100 nm) show high abundances of hydrogen (1,116 to 2,516 ppm) with extremely low δD values (-908 to -992‰), implying nearly exclusively a SW origin. The hydrogen-content depth distribution in the grain rims is phase-dependent, either bell-shaped for glass or monotonic decrease for mineral grains. This reveals the dynamic equilibrium between implantation and outgassing of SW-hydrogen in soil grains on the lunar surface. Heating experiments on a subset of the grains further demonstrate that the SW-implanted hydrogen could be preserved after burial. By comparing with the Apollo data, both observations and simulations provide constraints on the governing role of temperature (latitude) on hydrogen implantation/migration in lunar soils. We predict an even higher abundance of hydrogen in the grain rims in the lunar polar regions (average ~9,500 ppm), which corresponds to an estimation of the bulk water content of ~560 ppm in the polar soils assuming the same grain size distribution as Apollo soils, consistent with the orbit remote sensing result.

Modeling, analysis, and demonstration of a carrier-injection electro-absorption modulator at 2 µm on Ge-on-Si platform.

In this paper, a carrier-injection electro-absorption modulator (EAM) at 2 µm is demonstrated on Ge-on-Si platform. The EAM shows a compact size and high modulation efficiency due to the strong free-carrier electroabsorption (FCEA) effect in Ge. A modulation depth of 40 dB can be obtained under the injection current of only 420 mA. Small-signal frequency response measurement is performed and a small-signal equivalent circuit model is proposed. Based on reflection coefficients and equivalent circuit, the frequency response of carrier-injection EAM is discussed in detail. The 500 Mbps open eye diagram verifies the data-processing capacity of our EAM at 2 µm wavelength for its application in biological, chemical molecular detection, and infrared imaging systems.

GeSn resonance cavity enhanced photodetector with gold bottom reflector for the L band optical communication.

In this work, GeSn resonant cavity enhanced (RCE) p-i-n photodetectors (PDs) with 3.7% Sn content in a GeSn layer were fabricated on a silicon on insulator (SOI) substrate. The gold (Au) layer and the deposited SiO2 layer constitute the bottom reflector and top reflector of the RCE detectors, respectively. The GeSn RCE PD has three resonant peaks and its responsivity is improved about 4.5 times at 1630 nm, compared with GeSn PDs without a gold bottom mirror. The cutoff wavelength of GeSn RCE PDs is up to 1820 nm, while it is only 1730 nm for GeSn PDs without a gold reflector. The responsivity of RCE PDs at 1630 nm reaches 0.126 A/W and 3-dB bandwidth at about 36 GHz is achieved. These results indicate that the RCE structure is an effective approach for enhancing the GeSn PD performance operated at the L band.

The MdBBX22-miR858-MdMYB9/11/12 module regulates proanthocyanidin biosynthesis in apple peel.

Proanthocyanidins (PAs) have antioxidant properties and are beneficial to human health. The fruit of apple (Malus × domestica Borkh.), especially the peel, is rich in various flavonoids, such as PAs, and thus is an important source of dietary antioxidants. Previous research on the regulation of PAs in apple has mainly focussed on the transcription level, whereas studies conducted at the post-transcriptional level are relatively rare. In this study, we investigated the function of mdm-miR858, a miRNA with multiple functions in plant development, in the peel of apple fruit. We showed that mdm-miR858 negatively regulated PA accumulation by targeting MdMYB9/11/12 in the peel. During fruit development, mdm-miR858 expression was negatively correlated with MdMYB9/11/12 expression and PA accumulation. A 5'-RACE experiment, GUS staining assays and transient luminescent assays indicated that mdm-miR858 cleaved and inhibited the expression of MdMYB9/11/12. Overexpression of mdm-miR858 in apple calli, tobacco and Arabidopsis reduced the accumulation of PAs induced by overexpression of MdMYB9/11/12. Furthermore, we found that MdBBX22 bound to the mdm-miR858 promoter and induced its expression. Overexpression of MdBBX22 induced the expression of mdm-miR858 to inhibit the accumulation of PAs in apple calli overexpressing MdMYB9/11/12. Under light stress, MdBBX22 induced mdm-miR858 expression to inhibit PA accumulation and thereby indirectly enhanced anthocyanin synthesis in the peel. The present results revealed that the MdBBX22-miR858-MdMYB9/11/12 module regulates PA accumulation in apple. The findings provide a reference for further studies of the regulatory mechanism of PA accumulation and the relationship between PAs and anthocyanins.

A non-motorized spectro-goniometric system to measure the bi-directional reflectance spectra of particulate surfaces in the visible and near-infrared.

Reflectance spectroscopy is a powerful tool for remotely identifying the compositional and physical properties of surface materials. Due to the anisotropic scattering nature of most surfaces, the spectral features, including the absolute reflectance value, spectral slope, and band depth, are influenced by illumination and viewing configurations. Therefore, it is important to understand how spectral features vary with illumination and observation geometries for various particulate surfaces through laboratory measurements. Here, we describe a non-motorized spectro-goniometric system capable of measuring the bi-directional reflectance of particulate surfaces in the upper hemisphere in the wavelength range from 350 to 2150 nm. The incident and the viewing zenith angles can be varied from 0° to 55° and from 0° to 70°, respectively. The relative viewing azimuth angle can be varied from 0° to 360°. Measurements on Labsphere Spectralon agree well with measurements done with other instruments. We also present measurement results on two typical planetary analog materials, the JSC-1A Martian soil simulant and the JSC-1A lunar regolith simulant.

MdBBX21, a B-Box Protein, Positively Regulates Light-Induced Anthocyanin Accumulation in Apple Peel.

The red coloration of apple (Malus × domestica Borkh.) is due to the accumulation of anthocyanins in the fruit peel. Light is essential for anthocyanin biosynthesis in apple. In this study, we performed a transcriptome sequencing (RNA-seq) analysis of apple fruit exposed to light after unbagging. The identified differentially expressed genes included MdBBX21, which is homologous to Arabidopsis BBX21, suggesting it may be involved in light-induced anthocyanin biosynthesis. Additionally, MdBBX21 was localized in the nucleus and its gene was expressed earlier than MdMYB1 in apple peel treated with light. Overexpressing MdBBX21 in Arabidopsis and apple calli under light increased anthocyanin accumulation. Dual-luciferase and yeast one-hybrid assays confirmed that MdBBX21 binds to the MdHY5, MdBBX20, and MdBBX22-1/2 promoters and induces expression. At the same time, MdHY5 can also activate the expression of MdBBX21. Furthermore, bimolecular fluorescence complementation and yeast two-hybrid assays demonstrated that MdBBX21 can interact with MdHY5. This interaction can significantly enhance MdMYB1 promoter activity. These findings clarify the molecular mechanism by which MdBBX21 positively regulates light-induced anthocyanin accumulation in apple.

Evaluation of Physiological Characteristics, Soluble Sugars, Organic Acids and Volatile Compounds in 'Orin' Apples (Malus domestica) at Different Ripening Stages.

'Orin' is a popular apple cultivar, which has a yellow-green appearance, pleasant taste, and unique aroma. However, few studies on the fruit quality characteristics of 'Orin' apples have been reported before. In this study, changes of the physiological characteristics were measured at different ripening stages, and the soluble sugars and organic acids were determined by high-performance liquid chromatography (HPLC). Volatile compounds were identified using the headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). During the fruit ripening, the 'Orin' apple fruit weight, size, and total soluble solid were gradually increased by contrast with the titratable acidity, and the firmness decreased. The content of four soluble sugars reached the maximum at the 180 days after full bloom (DAFB) stage. Malic acid was measured as the most abundant organic acid in 'Orin' apples. Ethyl butyrate, hexyl propanoate, hexyl acetate and butyl acetate belonging to esters with high odor activity values (OAVs) could be responsible for the typical aroma of 'Orin' apples. The aim of this work was to provide information on the flavor characteristics of 'Orin' apples and promote this apple cultivar for marketing and processing in the future.

mdm-miR828 Participates in the Feedback Loop to Regulate Anthocyanin Accumulation in Apple Peel.

Anthocyanins are responsible for the red pigmentation in the peel of apple (Malus × domestica Borkh.) fruit. Relatively few studies have investigated anthocyanins at the posttranscriptional level. MicroRNAs play an important role in plant growth and development by regulating gene expression at the posttranscriptional level. In this study, mdm-miR828 showed a relatively low expression level during the rapid fruit coloration period. However, the mdm-miR828 expression level increased in the late fruit coloration stage. Overexpression of mdm-miR828 inhibited anthocyanin synthesis in apple and Arabidopsis. Dual-luciferase and yeast one-hybrid assays showed that MdMYB1 is capable of binding to the promoter of mdm-MIR828b to promote its expression. The results indicate that mdm-miR828 is involved in a feedback regulatory mechanism associated with anthocyanin accumulation in apple. In addition, mdm-miR828 is involved in the inhibition of anthocyanin accumulation in response to high temperature.

Radiometric calibration of thermal emission data from the Asteroid and Lunar Environment Chamber (ALEC).

The vacuum and thermal environment of airless planetary surfaces, particularly those dominated by a particulate regolith such as the Moon and asteroids, produces intense near-surface thermal gradients that can substantially alter their thermal emissivity spectra when compared with spectra collected at ambient terrestrial conditions. Therefore, spectroscopic measurements acquired under conditions designed to simulate the radiation environment in which remote measurements of airless bodies are made should be used as the basis for interpreting those data. As a foundation for this goal, we report the radiometric calibration of thermal infrared emission data collected with a Fourier transform infrared spectrometer integrated with the custom Asteroid and Lunar Environment Chamber (ALEC) at Brown University. This chamber is designed to simulate the environment of airless planetary bodies by evacuating the atmospheric gasses to vacuum (<10-4 mbar), cooling the chamber with a flow of liquid nitrogen, heating the base and sides of samples with temperature-controlled sample cups, and heating the top of samples with an external light source. We present a new method for deriving sample emissivity based on the absolute radiometry properties of our system, focusing on the 400-2000 cm-1 wavenumber range. This method produces calibrated radiance spectra from calibration targets, and particulate samples and those spectra are used to derive emissivity spectra. We demonstrate that the ALEC system and data reduction methods successfully replicate independently determined spectral properties of particulate samples under both ambient and cold, vacuum conditions. The ALEC system is shown to be capable of supporting ongoing and future planetary exploration of airless surfaces by facilitating careful investigation of meteorites, lunar samples, and planetary materials at an array of environmental conditions.

Transcriptome profiling of anthocyanin biosynthesis in the peel of 'Granny Smith' apples (Malus domestica) after bag removal.

BACKGROUND: Bagging is commonly used to enhance red pigmentation and thereby improve fruit quality of apples (Malus domestica). The green-skinned apple cultivar 'Granny Smith' develops red pigmentation after bagging removal, but the signal transduction pathways mediating light-induced anthocyanin accumulation in apple peel are yet to be defined. The aim of this study was to identify the mechanisms underpinning red pigmentation in 'Granny Smith' after bag removal based on transcriptome sequencing. RESULTS: The anthocyanin content in apple peel increased considerably after bag removal, while only trace amounts of anthocyanins were present in the peel of unbagged and bagged fruits. RNA sequencing identified 18,152 differentially expressed genes (DEGs) among unbagged, bagged, and bag-removed fruits at 0, 4, and 10 days after bag removal. The DEGs were implicated in light signal perception and transduction, plant hormone signal transduction, and antioxidant systems. Weighted gene co-expression network analysis of DEGs generated a module of 23 genes highly correlated with anthocyanin content. The deletion of - 2026 to - 1870 bp and - 1062 to - 964 bp regions of the MdMYB1 (LOC103444202) promoter induced a significant decrease in glucuronidase activity and anthocyanin accumulation in apple peel. CONCLUSIONS: Bagging treatment can induce red pigmentation in 'Granny Smith' via altering the expression patterns of genes involved in crucial signal transduction and biochemical metabolic pathways. The - 2026 to - 1870 bp and - 1062 to - 964 bp regions of the MdMYB1 promoter are essential for MdMYB1-mediated regulation of anthocyanin accumulation in the 'Granny Smith' apple cultivar. The findings presented here provide insight into the mechanisms of coloration in the peel of 'Granny Smith' and other non-red apple cultivars.

Transcriptome Profiling Reveals Transcriptional Regulation by DNA Methyltransferase Inhibitor 5-Aza-2'-Deoxycytidine Enhancing Red Pigmentation in Bagged "Granny Smith" Apples (Malus domestica).

The red color of apples (Malus domestica) is an attractive trait for consumers. The green skinned "Granny Smith" cultivar develops red pigmentation after bagging treatment. DNA methylation plays an important role in various developmental processes in plants. To explore the possible functions of DNA methylation in the pigmentation of bagged "Granny Smith" apples, we first analyzed the anthocyanin content of fruit skin following treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (5-aza-dC). The results revealed an increase in anthocyanin content in bagged fruits following 5-aza-dC treatment, while no anthocyanins were detected in unbagged fruits. In addition, 8482 differentially expressed genes between 5-aza-dC-treated and control groups were identified in bagged fruits by RNA sequencing, including genes encoding transcription factors, enzymes related to anthocyanin accumulation, and methylases. Changes in the expression of these genes may be responsible for 5-aza-dC-induced red pigmentation in bagged fruits of "Granny Smith". The findings provide novel evidence for the involvement of DNA methylation in the red pigmentation of non-red-skinned apples.

The effect of promoter methylation on MdMYB1 expression determines the level of anthocyanin accumulation in skins of two non-red apple cultivars.

BACKGROUND: Fruit color in apple (Malus domestica Borkh.) is ascribed mainly to the accumulation of anthocyanin pigments, and is an important trait for determining fruit market acceptance. Bagging is a commonly used treatment to enhance the red pigmentation in apple skin. The MdMYB1 transcription factor gene plays an important role in the biosynthesis of anthocyanin in apple after bag removal, but little is known about how MdMYB1 transcription is regulated. RESULTS: In this study, we investigated pigmentation in the non-red skinned cultivars 'Granny Smith' and 'Golden Delicious' after bag removal. The fruit skins of the two cultivars showed red/pink pigmentation after bag treatment. Transcript levels of MdMYB1, the master regulator of anthocyanin biosynthesis in apple, increased, and showed a correlation with anthocyanin content in both cultivars after bag removal. The MdMYB1 genomic sequences were compared in the two cultivars, which showed that the green-fruited cultivar 'Granny Smith' harbors the MdMYB1-1 and MdMYB1-2 alleles, while the yellow-fruited cultivar 'Golden Delicious' harbors only MdMYB1-2. A comparison of methylation levels in the 2 kb region upstream of the MdMYB1 ATG between the bag-treated fruits after removal from the bags and the unbagged fruits showed a correlation between hypomethylation and the red-skin phenotype in 'Granny Smith'. Moreover, 'Granny Smith' fruits responded to treatment with 5-aza-2'-deoxycytidine, an inducer of DNA demethylation. An investigation of the MdMYB1 promoter in 'Granny Smith' showed reduced methylation in the regions - 2026 to - 1870 bp, - 1898 to - 1633 bp, and - 541 to - 435 bp after bag removal and 5-aza-2'-deoxycytidine treatments. CONCLUSIONS: Differences in anthocyanin levels between 'Granny Smith' and 'Golden Delicious' can be explained by differential accumulation of MdMYB1-specific mRNA. Different levels of MdMYB1 transcripts in the two cultivars are associated with methylation levels in the promoter region. Hypomethylation of the MdMYB1 promoter is correlated with the formation of red pigmentation in 'Granny Smith' fruit skins. As a result, red pigmentation in Granny Smith' was more intense than in 'Golden Delicious' fruits after bag removal.

Analysis of ß-Galactosidase During Fruit Development and Ripening in Two Different Texture Types of Apple Cultivars.

ß-galactosidase (ß-Gal), one of the cell wall modifying enzymes, plays an important role in fruit ripening and softening. However, its role in apple fruit texture remains unclear. In this study, the role of ß-Gal was analyzed in two apple cultivars, 'Fuji' and 'Qinguan,' which are characterized by different fruit texture types, during fruit development and ripening. The firmness and pectin content of the fruits rapidly decreased and were much lower in 'Fuji' than in 'Qinguan' from 105 days after full bloom (DAFB). Transmission electron microscopy showed that the pectin-rich middle lamella was substantially degraded from 105 to 180 DAFB in the two apple cultivars. However, the degradation was more severe in 'Fuji' than in 'Qinguan.' Subcellular localization analysis showed that the Mdß-Gal1, Mdß-Gal2, and Mdß-Gal5 proteins were located in the cell wall. ß-Gal activity continuously increased during all fruit developmental stages and was much higher in the mature fruits of 'Fuji' than in those of 'Qinguan,' indicating that pectin was degraded by ß-Gal. Consistent with the enzyme activities, expression levels of ß-Gal genes (Mdß-Gal1, Mdß-Gal2, and Mdß-Gal5) showed only slight changes from 60 to 105 DAFB but then dramatically increased until fruit ripening, with higher values in 'Fuji' than in 'Qinguan.' Furthermore, we found that activities of deletion derivatives in the Mdß-Gal2 promoter and transcript level of Mdß-Gal2 were induced by the treatment with methyl jasmonate (MeJA) and ethylene (ETH) hormones. Two ETH and one MeJA hormone-responsive elements were identified by analyzing the promoter sequence. These results suggest that ß-Gals, induced by ETH and MeJA, are involved in different fruit texture types of apple cultivars by influencing the degradation of pectin during the mature fruit stage.

Overexpression of VpEIFP1, a novel F-box/Kelch-repeat protein from wild Chinese Vitis pseudoreticulata, confers higher tolerance to powdery mildew by inducing thioredoxin z proteolysis.

An F-box protein (VpEIFP1) induced by Erysiphe necator was isolated from Vitis pseudoreticulata, a wild Chinese grapevine species naturally resistant to powdery mildew (PM). It contains an F-box domain and two Kelch-repeat motifs. Expression profiles indicate the VpEIFP1 is strongly induced at both transcriptional and translational levels by PM infection. A subcellular localisation assay showed that VpEIFP1 is predominantly located in the nucleus and cytoplasm. Overexpression of VpEIFP1 accelerated the accumulation of hydrogen peroxide (H2O2) and up-regulated the expressions of ICS2, NPR1 and PR1 involved in defence responses, resulting in suppression of PM germination and growth. As an F-box protein, VpEIFP1 interacts with thioredoxin z (VpTrxz) in the yeast-two-hybrid (Y2H) assay and in the bimolecular fluorescence complementation (BiFC) assay. Decreased amounts of VpTrxz protein in transgenic grapevine leaves overexpressing VpEIFP1 were restored by proteasome inhibitor MG132, implying that VpEIFP1 mediated VpTrxz for degradation through the SCFVpEIFP1 (Skp1-Cullin-F-box) E3 ubiquitin ligase complex. The RNA interference line of VpTrxz showed increased H2O2 accumulation following PM inoculation. We propose VpEIFP1 positively modulates the grapevine defence response to PM by inducing the degradation of VpTrxz via the ubiquitin/26S proteasome system.