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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

VpPUB24, a novel gene from Chinese grapevine, Vitis pseudoreticulata, targets VpICE1 to enhance cold tolerance.

The ubiquitination system plays important roles in the degradation and modification of substrate proteins. In this study, we characterize a putative U-box type E3 ubiquitin ligase gene, VpPUB24 (plant U-box protein 24), from Chinese wild grapevine, Vitis pseudoreticulata accession Baihe-35-1. We show that VpPUB24 is induced by a number of stresses, especially cold treatment. Real-time PCR analysis indicated that the PUB24 transcripts were increased after cold stress in different grapevine species, although the relative expression level was different. In grapevine protoplasts, we found that VpPUB24 was expressed at a low level at 22 °C but accumulated rapidly following cold treatment. A yeast two-hybrid assay revealed that VpPUB24 interacted physically with VpICE1. Further experiments indicated that VpICE1 is targeted for degradation via the 26S proteasome and that the degradation is accelerated by VpHOS1, and not by VpPUB24. Immunoblot analyses indicated that VpPUB24 promotes the accumulation of VpICE1 and suppresses the expression of VpHOS1 to regulate the abundance of VpICE1. Furthermore, VpICE1 promotes transcription of VpPUB24 at low temperatures. We also found that VpPUB24 interacts with VpHOS1 in a yeast two-hybrid assay. Additionally, over-expression of VpPUB24 in Arabidopsis thaliana enhanced cold tolerance. Collectively, our results suggest that VpPUB24 interacts with VpICE1 to play a role in cold stress.

RING-H2-type E3 gene VpRH2 from Vitis pseudoreticulata improves resistance to powdery mildew by interacting with VpGRP2A.

Grapevine is one of the world's most important fruit crops. European cultivated grape species have the best fruit quality but show almost no resistance to powdery mildew (PM). PM caused by Uncinula necator is a harmful disease that has a significant impact on the economic value of the grape crop. In this study, we examined a RING-H2-type ubiquitin ligase gene VpRH2 that is associated with significant PM-resistance of Chinese wild-growing grape Vitis pseudoreticulata accession Baihe-35-1. The expression of VpRH2 was clearly induced by U. necator inoculation compared with its homologous gene VvRH2 in a PM-susceptible grapevine V. vinifera cv. Thompson Seedless. Using a yeast two-hybrid assay we confirmed that VpRH2 interacted with VpGRP2A, a glycine-rich RNA-binding protein. The degradation of VpGRP2A was inhibited by treatment with the proteasome inhibitor MG132 while VpRH2 did not promote the degradation of VpGRP2A. Instead, the transcripts of VpRH2 were increased by over-expressing VpGRP2A while VpRH2 suppressed the expression of VpGRP2A. Furthermore, VpGRP2A was down-regulated in both Baihe-35-1 and Thompson Seedless after U. necator inoculation. Specifically, we generated VpRH2 overexpression transgenic lines in Thompson Seedless and found that the transgenic plants showed enhanced resistance to powdery mildew compared with the wild-type. In summary, our results indicate that VpRH2 interacts with VpGRP2A and plays a positive role in resistance to powdery mildew.

Highly interactive nature of flower-specific enhancers and promoters, and its potential impact on tissue-specific expression and engineering of multiple genes or agronomic traits.

Molecular stacking enables multiple traits to be effectively engineered in crops using a single vector. However, the co-existence of distinct plant promoters in the same transgenic unit might, like their mammalian counterparts, interfere with one another. In this study, we devised a novel approach to investigate enhancer-promoter and promoter-promoter interactions in transgenic plants and demonstrated that three of four flower-specific enhancer/promoters were capable of distantly activating a pollen- and stigma-specific Pps promoter (fused to the cytotoxic DT-A gene) in other tissues, as revealed by novel tissue ablation phenotypes in transgenic plants. The NtAGI1 enhancer exclusively activated stamen- and carpel-specific DT-A expression, thus resulting in tissue ablation in an orientation-independent manner; this activation was completely abolished by the insertion of an enhancer-blocking insulator (EXOB) between the NtAGI1 enhancer and Pps promoter. Similarly, AGL8 and AP1Lb1, but not AP1La, promoters also activated distinct tissue-specific DT-A expression and ablation, with the former causing global growth retardation and the latter ablating apical inflorescences. While the tissue specificity of the enhancer/promoters generally defined their activation specificities, the strength of their activity in particular tissues or developmental stages appeared to determine whether activation actually occurred. Our findings provide the first evidence that plant-derived enhancer/promoters can distantly interact/interfere with one another, which could pose potential problems for the tissue-specific engineering of multiple traits using a single-vector stacking approach. Therefore, our work highlights the importance of adopting enhancer-blocking insulators in transformation vectors to minimize promoter-promoter interactions. The practical and fundamental significance of these findings will be discussed.

Effects of Spectralon absorption on reflectance spectra of typical planetary surface analog materials.

Acquiring accurate visible and near-infrared (VisNIR) reflectance values of atmosphereless celestial bodies is very important in inferring the physical and geological properties of their surficial materials. When a calibration target with inherent non-trivial absorption features is used, the calibrated reflectance would essentially always contain spurious spectral features and the spectroscopic data may easily be misinterpreted if the artifact is not properly taken care of. We demonstrate with laboratory reflectance measurements that the VisNIR spectra of three typical planetary surface analog materials, lunar simulant JSC-1A, olivine and pyroxene grains, have an artificial peak at 2.1 µm when Spectralon-type plaque made of polytetrafluoroethylene is used as the calibration target in the NIR region. The degree of severity of this artifact is dependent on the strength of the 2.0 µm absorption feature of the mineral. Empirical methods are proposed to remove this artifact to bring the spectra close to that calibrated by a gold mirror which does not have any conspicuous absorption features in the NIR region. The correction methods may be applied to reflectance data acquired by the VisNIR imaging spectrometer onboard the Yutu Rover of the Chinese Chang'E 3 lunar mission which employed an onboard Spectralon-type calibration target.

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.

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.

The Chinese wild grapevine (Vitis pseudoreticulata) E3 ubiquitin ligase Erysiphe necator-induced RING finger protein 1 (EIRP1) activates plant defense responses by inducing proteolysis of the VpWRKY11 transcription factor.

Ubiquitin-mediated regulation responds rapidly to specific stimuli; this rapidity is particularly important for defense responses to pathogen attack. Here, we investigated the role of the E3 ubiquitin ligase Erysiphe necator-induced RING finger protein 1 (EIRP1) in the defense response of Chinese wild grapevine Vitis pseudoreticulata. The regulatory function of E3 ubiquitin ligase EIRP1 was investigated using molecular, genetic and biochemical approaches. EIRP1 encodes a C3HC4-type Really Interesting New Gene (RING) finger protein that harbors E3 ligase activity. This activity requires the conserved RING domain, and VpWRKY11 also interacts with EIRP1 through the RING domain. VpWRKY11 localizes to the nucleus and activates W-box-dependent transcription in planta. EIRP1 targeted VpWRKY11 in vivo, resulting in VpWRKY11 degradation. The expression of EIRP1 and VpWRKY11 responds rapidly to powdery mildew in Vitis pseudoreticulata grapevine; also, overexpression of EIRP1 in Arabidopsis confers enhanced resistance to the pathogens Golovinomyces cichoracearum and Pseudomonas syringae pv tomato DC3000. Our data suggest that the EIRP1 E3 ligase positively regulates plant disease resistance by mediating proteolysis of the negative regulator VpWRKY11 via degradation by the 26S proteasome.

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.

Identification of the dehydrin gene family from grapevine species and analysis of their responsiveness to various forms of abiotic and biotic stress.

BACKGROUND: Dehydrins (DHNs) protect plant cells from desiccation damage during environmental stress, and also participate in host resistance to various pathogens. In this study, we aimed to identify and characterize the DHN gene families from Vitis vinifera and wild V. yeshanensis, which is tolerant to both drought and cold, and moderately resistant to powdery mildew. RESULTS: Four DHN genes were identified in both V. vinifera and V. yeshanensis, which shared a high sequence identity between the two species but little homology between the genes themselves. These genes were designated DHN1, DHN2, DHN3 and DHN4. All four of the DHN proteins were highly hydrophilic and were predicted to be intrinsically disordered, but they differed in their isoelectric points, kinase selectivities and number of functional motifs. Also, the expression profiles of each gene differed appreciably from one another. Grapevine DHN1 was not expressed in vegetative tissues under normal growth conditions, but was induced by drought, cold, heat, embryogenesis, as well as the application of abscisic acid (ABA), salicylic acid (SA), and methyl jasmonate (MeJA). It was expressed earlier in V. yeshanensis under drought conditions than in V. vinifera, and also exhibited a second round of up-regulation in V. yeshanensis following inoculation with Erysiphe necator, which was not apparent in V. vinifera. Like DHN1, DHN2 was induced by cold, heat, embryogenesis and ABA; however, it exhibited no responsiveness to drought, E. necator infection, SA or MeJA, and was also expressed constitutively in vegetative tissues under normal growth conditions. Conversely, DHN3 was only expressed during seed development at extremely low levels, and DHN4 was expressed specifically during late embryogenesis. Neither DHN3 nor DHN4 exhibited responsiveness to any of the treatments carried out in this study. Interestingly, the presence of particular cis-elements within the promoter regions of each gene was positively correlated with their expression profiles. CONCLUSIONS: The grapevine DHN family comprises four divergent members. While it is likely that their functions overlap to some extent, it seems that DHN1 provides the main stress-responsive function. In addition, our results suggest a close relationship between expression patterns, physicochemical properties, and cis-regulatory elements in the promoter regions of the DHN genes.