Pollen transcriptomic analysis provided insights into understanding the molecular mechanisms underlying grafting-induced improvement in potato fertility

IntroductionHeterologous grafting has been proven to be a valid approach to improving potato fertility, especially when grafting potatoes with other Solanaceae family plants. However, the mechanisms underlying grafting-induced improvement in potato fertility are still unknown.MethodsIn this study, a poor-fertility potato cultivar “Qingshu No. 9” (Q9) was grafted with a tomato cultivar “Zhongyan988” (ZY988) to study the effects of heterologous grafting in the former. The tuber yield was controlled by different grafting and cultivation approaches, and the correlation between tuber yield and pollen vigor was studied. Comparative transcriptomic analysis of the potential mechanisms of pollen in potato scion fertility changes.ResultGrafting with the tomato rootstock effectively promoted the flower and fruit formation in the scion potato and improved its pollen viability by 15%–20%. In addition, a significant negative correlation was observed between the potato tuber yield and pollen viability, suggesting a potential impact on the metabolic regulatory network related to tuber formation. From the comparative transcriptomic analysis between the pollens from Q9 self-grafted plants and Q9-tomato grafting scion, 513 differentially expressed genes (DEGs) were identified. These DEGs were found to be related to gametophyte and pollen development, carbohydrate metabolism, and protein processing. Thus, these DEGs might be involved in improved fertility after reduced tuberization in plants subjected to heterologous grafting.DiscussionPotato/tomato heterologous grafting significantly improved the pollen viability of scion potatoes and was associated with the absence of potato tubers. Heterologous grafting promotes the transcription of genes related to protein processing, carbohydrate metabolism, and pollen development in pollen cells, resulting in the production of fertile pollen. Our results provided initial clues to understanding the improvement of potato fertility using the heterologous grafting method, which might be a useful tool in assisted potato breeding

Single-step replacement of an unreactive C-H bond by a C-S bond using polysulfide as the direct sulfur source in anaerobic ergothioneine biosynthesis

Ergothioneine, a natural longevity vitamin and antioxidant, is a thiol-histidine derivative. Recently, two types of biosynthetic pathways were reported. In the aerobic ergothioneine biosynthesis, a non-heme iron enzyme incorporates a sulfoxide to an sp2 C-H bond in trimethyl-histidine (hercynine) through oxidation reactions. In contrast, in the anaerobic ergothioneine biosynthetic pathway in a green sulfur bacterium, Chlorobium limicola, a rhodanese domain containing protein (EanB) directly replaces this unreactive hercynine C-H bond with a C-S bond. Herein, we demonstrate that polysulfide (HSSnSR) is the direct sulfur-source in EanB-catalysis. After identifying EanB's substrates, X-ray crystallography of several intermediate states along with mass spectrometry results provide additional mechanistic details for this reaction. Further, quantum mechanics/molecular mechanics (QM/MM) calculations reveal that protonation of Nπ of hercynine by Tyr353 with the assistance of Thr414 is a key activation step for the hercynine sp2 C-H bond in this trans-sulfuration reaction.R01 GM106443 - NIGMS NIH HHS; R41 AT010878 - NCCIH NIH HHSAccepted manuscrip

Unimodal productivity-biodiversity relationship along the gradient of multidimensional resources across Chinese grasslands

Resources can affect plant productivity and biodiversity simultaneously and thus are key drivers of their relationships in addition to plant-plant interactions. However, most previous studies only focused on a single resource while neglecting the nature of resource multidimensionality. Here we integrated four essential resources for plant growth into a single metric of resource diversity (RD) to investigate its effects on the productivity-biodiversity relationship (PBR) across Chinese grasslands. Results showed that habitats differing in RD have different PBRs − positive in low-resource habitats, but neutral in medium- and high-resource ones—while collectively, a weak positive PBR was observed. However, when excluding direct effects of RD on productivity and biodiversity, PBR in high-resource habitats became negative, which leads to a unimodal instead of a positive PBR along the RD gradient. By integrating resource effects and changing plant-plant interactions into a unified framework with the RD gradient, our work contributes to uncovering underlying mechanisms for inconsistent PBRs at large scales

Consistent forest leaf area index retrieval using ground and airborne data

L’indice de surface foliaire (Leaf Area Index, LAI), défini comme la moitié de la surface foliaire par unité de surface de sol, est un paramètre clé du cycle écologique de la Terre, et sa précision d'acquisition a toujours la nécessité et la possibilité d'amélioration. La technologie du scanner laser actif offre une possibilité d'obtention cohérente du LAI à plusieurs échelles, car le scanner laser terrestre et le scanner laser aéroporté fonctionnent sur le même mécanisme physique. Cependant, les informations tridimensionnelles du scanner laser ne sont pas complètement explorées dans les méthodes actuelles et les théories traditionnelles ont besoin d'adaptation. Dans cette thèse, le modèle de distribution de longueur de trajet est introduit pour corriger l'effet d’agrégation, et il est appliqué aux données du scanner laser terrestre et du scanner laser aéroporté. La méthode d'obtention de la distribution de longueur de trajet de différentes plates-formes est étudiée et le modèle de récupération cohérent est établi. Cette méthode permet d’améliorer la mesure du LAI des arbres individuels dans les zones urbaines et la cartographie LAI dans les forêts naturelles, et ses résultats sont cohérents à différentes échelles. Le modèle devrait faciliter la détermination cohérente de l'indice de surface foliaire des forêts à l'aide de données au sol et aéroportées.Leaf Area Index (LAI), defined as one half of the total leaf area per unit ground surface area, is a key parameter of vegetation structure for modeling Earth's ecological cycle and its acquisition accuracy always has the need and opportunity for improvement. Active laser scanning provides an opportunity for consistent LAI retrieval at multiple scales because terrestrial laser scanning (TLS) and airborne laser scanning (ALS) have the similar physical mechanism. However, the three-dimensional information of laser scanning is not fully explored in current methods and the traditional theories require adaptation. In this thesis, the path length distribution model is proposed to model the clumping effect, and it is applied to the TLS and ALS data. The method of obtaining the path length distribution of different platforms is studied, and the consistent retrieval model is established. This method is found to improve the individual tree measurement in urban areas and LAI mapping in natural forest, and its results at consistent at different scales. The model is expected to facilitate the consistent retrieval of the forest leaf area index using ground and airborne data

Estimation cohérente de l'indice de surface foliaire en utilisant des données terrestres et aéroportées

Leaf Area Index (LAI), defined as one half of the total leaf area per unit ground surface area, is a key parameter of vegetation structure for modeling Earth's ecological cycle and its acquisition accuracy always has the need and opportunity for improvement. Active laser scanning provides an opportunity for consistent LAI retrieval at multiple scales because terrestrial laser scanning (TLS) and airborne laser scanning (ALS) have the similar physical mechanism. However, the three-dimensional information of laser scanning is not fully explored in current methods and the traditional theories require adaptation. In this thesis, the path length distribution model is proposed to model the clumping effect, and it is applied to the TLS and ALS data. The method of obtaining the path length distribution of different platforms is studied, and the consistent retrieval model is established. This method is found to improve the individual tree measurement in urban areas and LAI mapping in natural forest, and its results at consistent at different scales. The model is expected to facilitate the consistent retrieval of the forest leaf area index using ground and airborne data.L’indice de surface foliaire (Leaf Area Index, LAI), défini comme la moitié de la surface foliaire par unité de surface de sol, est un paramètre clé du cycle écologique de la Terre, et sa précision d'acquisition a toujours la nécessité et la possibilité d'amélioration. La technologie du scanner laser actif offre une possibilité d'obtention cohérente du LAI à plusieurs échelles, car le scanner laser terrestre et le scanner laser aéroporté fonctionnent sur le même mécanisme physique. Cependant, les informations tridimensionnelles du scanner laser ne sont pas complètement explorées dans les méthodes actuelles et les théories traditionnelles ont besoin d'adaptation. Dans cette thèse, le modèle de distribution de longueur de trajet est introduit pour corriger l'effet d’agrégation, et il est appliqué aux données du scanner laser terrestre et du scanner laser aéroporté. La méthode d'obtention de la distribution de longueur de trajet de différentes plates-formes est étudiée et le modèle de récupération cohérent est établi. Cette méthode permet d’améliorer la mesure du LAI des arbres individuels dans les zones urbaines et la cartographie LAI dans les forêts naturelles, et ses résultats sont cohérents à différentes échelles. Le modèle devrait faciliter la détermination cohérente de l'indice de surface foliaire des forêts à l'aide de données au sol et aéroportées

Consistent forest leaf area index retrieval using ground and airborne data

L’indice de surface foliaire (Leaf Area Index, LAI), défini comme la moitié de la surface foliaire par unité de surface de sol, est un paramètre clé du cycle écologique de la Terre, et sa précision d'acquisition a toujours la nécessité et la possibilité d'amélioration. La technologie du scanner laser actif offre une possibilité d'obtention cohérente du LAI à plusieurs échelles, car le scanner laser terrestre et le scanner laser aéroporté fonctionnent sur le même mécanisme physique. Cependant, les informations tridimensionnelles du scanner laser ne sont pas complètement explorées dans les méthodes actuelles et les théories traditionnelles ont besoin d'adaptation. Dans cette thèse, le modèle de distribution de longueur de trajet est introduit pour corriger l'effet d’agrégation, et il est appliqué aux données du scanner laser terrestre et du scanner laser aéroporté. La méthode d'obtention de la distribution de longueur de trajet de différentes plates-formes est étudiée et le modèle de récupération cohérent est établi. Cette méthode permet d’améliorer la mesure du LAI des arbres individuels dans les zones urbaines et la cartographie LAI dans les forêts naturelles, et ses résultats sont cohérents à différentes échelles. Le modèle devrait faciliter la détermination cohérente de l'indice de surface foliaire des forêts à l'aide de données au sol et aéroportées.Leaf Area Index (LAI), defined as one half of the total leaf area per unit ground surface area, is a key parameter of vegetation structure for modeling Earth's ecological cycle and its acquisition accuracy always has the need and opportunity for improvement. Active laser scanning provides an opportunity for consistent LAI retrieval at multiple scales because terrestrial laser scanning (TLS) and airborne laser scanning (ALS) have the similar physical mechanism. However, the three-dimensional information of laser scanning is not fully explored in current methods and the traditional theories require adaptation. In this thesis, the path length distribution model is proposed to model the clumping effect, and it is applied to the TLS and ALS data. The method of obtaining the path length distribution of different platforms is studied, and the consistent retrieval model is established. This method is found to improve the individual tree measurement in urban areas and LAI mapping in natural forest, and its results at consistent at different scales. The model is expected to facilitate the consistent retrieval of the forest leaf area index using ground and airborne data

Application Impersonation: Problems of OAuth and API Design in Online Social Networks

ABSTRACT OAuth 2.0 protocol has enjoyed wide adoption by Online Social Network (OSN) providers since its inception. Although the security guideline of OAuth 2.0 is well discussed in RFC6749 and RFC6819, many real-world attacks due to the implementation speci cs of OAuth 2.0 in various OSNs have been discovered. To our knowledge, previously discovered loopholes are all based on the misuse of OAuth and many of them rely on provider side or application side vulnerabilities/ faults beyond the scope of the OAuth protocol. It was generally believed that correct use of OAuth 2.0 is secure. In this paper, we show that OAuth 2.0 is intrinsically vulnerable to App impersonation attack due to its provision of multiple authorization ows and token types. We start by reviewing and analyzing the OAuth 2.0 protocol and some common API design problems found in many 1st-tiered OSNs. We then propose the App impersonation attack and investigate its impact on 12 major OSN providers. We demonstrate that, App impersonation via OAuth 2.0, when combined with additional API design features/ de ciencies, make largescale exploit and privacy-leak possible. For example, it becomes possible for an attacker to completely crawl a 200-million-user OSN within just one week and harvest data objects like the status list and friend list which are expected, by its users, to be private among only friends. We also propose xes that can be readily deployed to tackle the OAuth2.0-based App impersonation problem

Ecosystem-Dependent Responses of Vegetation Coverage on the Tibetan Plateau to Climate Factors and Their Lag Periods

The spatiotemporal variation characteristics of the Normalized Difference Vegetation Index (NDVI) and its climate response patterns are of significance in deepening our understanding of regional vegetation and climate change. The response of vegetation to climate factors varies spatially and may have lag periods. In this paper, we studied the spatiotemporal responses of vegetation to climatic factors on an ecosystem-dependent scale using GIMMS NDVI3g data and climatic parameters. Pure pixels with a single vegetation type were firstly extracted to reduce the influence of mixed vegetation types. Then, a lag correlation analysis was used to explore the lag effects of climatic parameters affecting NDVI. Finally, the stepwise regression method was adopted to calculate the regression equation for NDVI and meteorological data with the consideration of effect lag times. The results show that precipitation has significant lag effects on vegetation. Temperature is the main climatic factor that affects most vegetation types at the start of growing season. At the end of growing season, the temperate desert, temperate steppe, and temperate desert steppe are greatly affected by precipitation. Moreover, the alpine steppe, alpine desert, alpine meadow, and alpine sparse vegetation are greatly affected by temperature. The needleleaf forest, subalpine scrub, and broadleaf evergreen forest are sensitive to sunshine percentage during almost the whole growing season. These findings could contribute to a better understanding of the drivers and mechanisms of vegetation degradation on the Tibetan Plateau

Estimating plant area density of individual trees from discrete airborne laser scanning data using intensity information and path length distribution

Plant area density (PAD) of individual trees is an important structural indicator related to tree growth status, stress levels due to pests and diseases, photosynthesis potential, and evapotranspiration. Airborne laser scanning (ALS) provides unprecedented 3D information for mapping forest canopy parameters. Previous studies mainly focused on mapping stand-level and 2D leaf area index. This study proposes a method to estimate PAD from discrete and multiple return ALS data at individual tree scales. The proposed method uses path length distribution to eliminate crown-shape-induced clumping, as well as intensity information to estimate crown transmittance from relative low-density points. The path length distribution is derived from the 3D crown boundary contours created by an alpha shape algorithm, which explicitly considers the non-uniform LiDAR pulse penetration distances. Pulse intensity is calibrated with the nearest pure-ground pulse to mitigate the need for prior leaf and ground reflectance information, which can be used in areas with a heterogeneous background. The proposed method was evaluated both in virtual experiments as well as with terrestrial laser scanning (TLS) data. The virtual experiments used the large-scale remote sensing data and image simulation model (LESS) to simulate virtual ALS scanning data based on abstract and realistic canopies. Results showed that the ALS-derived PAD is highly accurate, with RMSE less than 0.02 and R2 > 0.99 for the abstract sphere and cube crowns, and RMSE = 0.19 and R2 = 0.578 for the realistic crowns. The comparison with TLS of a birch plot shows that the ALS-derived PAD is consistent with those derived from TLS, with RMSE = 0.14 and R2 = 0.46. This study demonstrated that using the full intensity and geometry information of a point cloud is capable of generating high-resolution forest parameters from ALS data

Large-Scale Analysis of the Spatiotemporal Changes of Net Ecosystem Production in Hindu Kush Himalayan Region

The Hindu Kush Himalayan (HKH) region is one of the most ecologically vulnerable regions in the world. Several studies have been conducted on the dynamic changes of grassland in the HKH region, but few have considered grassland net ecosystem productivity (NEP). In this study, we quantitatively analyzed the temporal and spatial changes of NEP magnitude and the influence of climate factors on the HKH region from 2001 to 2018. The NEP magnitude was obtained by calculating the difference between the net primary production (NPP) estimated by the Carnegie–Ames Stanford Approach (CASA) model and the heterotrophic respiration (Rh) estimated by the geostatistical model. The results showed that the grassland ecosystem in the HKH region exhibited weak net carbon uptake with NEP values of 42.03 gC∙m−2∙yr−1, and the total net carbon sequestration was 0.077 Pg C. The distribution of NEP gradually increased from west to east, and in the Qinghai–Tibet Plateau, it gradually increased from northwest to southeast. The grassland carbon sources and sinks differed at different altitudes. The grassland was a carbon sink at 3000–5000 m, while grasslands below 3000 m and above 5000 m were carbon sources. Grassland NEP exhibited the strongest correlation with precipitation, and it had a lagging effect on precipitation. The correlation between NEP and the precipitation of the previous year was stronger than that of the current year. NEP was negatively correlated with temperature but not with solar radiation. The study of the temporal and spatial dynamics of NEP in the HKH region can provide a theoretical basis to help herders balance grazing and forage