Silencing of the Wheat Protein Phosphatase 2A Catalytic Subunit TaPP2Ac Enhances Host Resistance to the Necrotrophic Pathogen Rhizoctonia cerealis

Eukaryotic type 2A protein phosphatases (protein phosphatase 2A, PP2A) consist of a scaffold subunit A, a regulatory subunit B, and a catalytic subunit C. Little is known about the roles of PP2Ac proteins that are involved in plant responses to necrotrophic fungal pathogens. Sharp eyespot, caused by the necrotrophic fungus Rhizoctonia cerealis, is a destructive disease of wheat (Triticum aestivum), an important staple food crop. Here, we isolated TaPP2Ac-4D from wheat, which encodes a catalytic subunit of the heterotrimeric PP2A, and characterized its properties and role in plant defense response to R. cerealis. Based on the sequence alignment of TaPP2Ac-4D with the draft sequences of wheat chromosomes from the International Wheat Genome Sequencing Consortium (IWGSC), it was found that TaPP2Ac-4D gene is located on the long arm of the wheat chromosome 4D and has two homologs assigned on wheat chromosomes 4A and 4B. Sequence and phylogenetic tree analyses revealed that the TaPP2Ac protein is a typical member of the PP2Ac family and belongs to the subfamily II. TaPP2Ac-4B and TaPP2Ac-4D displayed higher transcriptional levels in the R. cerealis-susceptible wheat cultivar Wenmai 6 than those seen in the resistant wheat line CI12633. The transcriptional levels of TaPP2Ac-4B and TaPP2Ac-4D were significantly elevated in wheat R. cerealis after infection and upon H2O2 treatment. Virus-induced gene silencing results revealed that the transcriptional knockdown of TaPP2Ac-4D and TaPP2Ac-4B significantly increased wheat resistance to R. cerealis infection. Meanwhile, the transcriptional levels of certain pathogenesis-related (PR) and reactive oxygen species (ROS)-scavenging enzyme encoding genes were increased in TaPP2Ac-silenced wheat plants. These results suggest that TaPP2Ac-4B and TaPP2Ac-4D negatively regulate defense response to R. cerealis infection possibly through modulation of the expression of certain PR and ROS-scavenging enzyme genes in wheat. This study reveals a novel function of the plant PP2Ac genes in plant immune responses

An adaptive observer for joint estimation of states and parameters in both state and output equations

International audienceAn adaptive observer is a recursive algorithm for joint state-parameter estimation of parameterized state-space systems. Previous works on globally convergent adaptive observers consider unknown parameters either in state equations or in output equations, but not in both of them. In this paper, a new adaptive observer is designed for linear time-varying systems with unknown parameters in both state and output equations. Its global convergence for simultaneous estimation of states and parameters is formally established under appropriate assumptions. A numerical example is presented to illustrate the performance of this adaptive observer

Next-generation sequencing yields a nearly complete mitochondrial genome of the Variegated Racerunner (Eremias Vermiculata) from Dunhuang Basin

The Variegated Racerunner, Eremias vermiculata, is widespread in Northwest China, southern Mongolia, and Zaisan Basin of Kazakhstan. In this study, a nearly complete mitochondrial genome (17,972 bp in length) of E. vermiculata from the Dunhuang Basin in Northwest China was determined by next-generation sequencing. Similar to the typical mtDNA of vertebrates, it contained two ribosomal RNA genes, 13 protein-coding genes (PCGs), 22 transfer RNA genes, and one control region (CR). With exception to the CR, all of the 37 genes were completely recovered. The concatenated PCGs were used to conduct Bayesian phylogenetic analyses together with mitogenome data of lacertids in GenBank. The resulting phylogenetic tree confirmed the monophyly of genus Eremias and its viviparous species as well as E. vermiculata, respectively. The mitogenome presented here will contribute to the examination of phylogeographic structure for E. vermiculata and understanding of mitochondrial DNA evolution in Eremias

Next-generation sequencing yields a nearly complete mitochondrial genome of the Multiocellated Racerunner (Eremias multiocellata) in Northwest China

The viviparous Multiocellated Racerunner, Eremias multiocellata, is widespread in North China, Mongolia, and the Tuva Republic of Russia. A nearly complete mitochondrial genome of one individual from the suburb of Jingyuan County in Northwest China was determined by next-generation sequencing. The mitogenome is 17,333 bp in size, comprising 2 ribosomal RNA genes, 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and one control region. The gene arrangement and composition is similar to the typical mitochondrial DNA of vertebrates. With exception to the control region, all of the 37 genes were completely recovered. The concatenated PCGs were used to conduct Bayesian phylogenetic analyses together with several related lizards with mitogenome data in GenBank. The resulting phylogenetic tree confirmed the monophyly of both genus Eremias and its viviparous group. The mitogenome sequence will provide fundamental data for resolving phylogenetic and genetic problems related to Eremias viviparity

Effects of biopolymer ratio and pH value on the complex formation between whey protein isolates and soluble Auricularia auricular polysaccharides

Biopolymer complexes fabricated by proteins and neutral polysaccharides have some specific and innovative functionalities. A better understanding of the interactions among these biopolymers might provide new insight into the applications of the complexes. Therefore, this study aimed to investigate the structural characteristics and molecular interaction mechanisms of whey protein isolates (WPI) and Auricularia auricular polysaccharides (APs). The turbidity analysis confirmed that the pH value and mixing ratio of the two polymers had strong effects on the formation of the APs-WPI complexes. All dispersions formed soluble complexes at approximately pH = 6.0 (pHc). APs-WPI self-assembles exhibited physically cross-linked networks under higher APs proportions, while they formed spherical complexes at higher WPI ratios. The addition of APs could alter the secondary structure of WPI, and the most noticeable changes were located in the regions of β-sheet and β-turn as confirmed by circular dichroism (CD) analysis. A molecular docking study showed that the amino acid residues of β-lactoglobulin complexed with the –COOH and –OH groups of APs. Hydrogen bonds and hydrophobic interactions, which were nonbonding contributions, played a key role in the formation of the APs-WPI complex. This study provided a basis for the development and application of APs in WPI-based beverages

Reducing Threading Dislocations of Single-Crystal Diamond via In Situ Tungsten Incorporation

A lower dislocation density substrate is essential for realizing high performance in single-crystal diamond electronic devices. The in-situ tungsten-incorporated homoepitaxial diamond by introducing tungsten hexacarbonyl has been proposed. A 3 × 3 × 0.5 mm3 high-pressure, high-temperature (001) diamond substrate was cut into four pieces with controlled experiments. The deposition of tungsten-incorporated diamond changed the atomic arrangement of the original diamond defects so that the propagation of internal dislocations could be inhibited. The SEM images showed that the etching pits density was significantly decreased from 2.8 × 105 cm−2 to 2.5 × 103 cm−2. The reduction of XRD and Raman spectroscopy FWHM proved that the double-layer tungsten-incorporated diamond has a significant effect on improving the crystal quality of diamond bulk. These results show the evident impact of in situ tungsten-incorporated growth on improving crystal quality and inhibiting the dislocations propagation of homoepitaxial diamond, which is of importance for high-quality diamond growth

Evaluating the Canopy Chlorophyll Density of Maize at the Whole Growth Stage Based on Multi-Scale UAV Image Feature Fusion and Machine Learning Methods

Maize is one of the main grain reserve crops, which directly affects the food security of the country. It is extremely important to evaluate the growth status of maize in a timely and accurate manner. Canopy Chlorophyll Density (CCD) is closely related to crop health status. A timely and accurate estimation of CCD is helpful for managers to take measures to avoid yield loss. Thus, many methods have been developed to estimate CCD with remote sensing data. However, the relationship between the CCD and the features used in these CCD estimation methods at different growth stages is unclear. In addition, the CCD was directly estimated from remote sensing data in most previous studies. If the CCD can be accurately estimated from the estimation results of Leaf Chlorophyll Density (LCD) and Leaf Area Index (LAI) remains to be explored. In this study, Random Forest (RF), Support Vector Machines (SVM), and Multivariable Linear Regression (MLR) were used to develop CCD, LCD, and LAI estimation models by integrating multiple features derived from unmanned aerial vehicle (UAV) multispectral images. Firstly, the performances of the RF, SVM, and MLR trained over spectral features (including vegetation indices and band reflectance; dataset I), texture features (dataset II), wavelet coefficient features (dataset III), and multiple features (dataset IV, including all the above datasets) were analyzed, respectively. Secondly, the CCDP was calculated from the estimated LCD and estimated LAI, and then the CCD was estimated based on multiple features and the CCDP was compared. The results show that the correlation between CCD and different features is significantly different at every growth stage. The RF model trained over dataset IV yielded the best performance for the estimation of LCD, LAI, and CCD (R2 values were 0.91, 0.97, and 0.97, and RMSE values were 6.59 μg/cm2, 0.35, and 24.85 μg/cm2). The CCD directly estimated from dataset IV is slightly closer to the ground truth CCD than the CCDP (R2 = 0.96, RMSE = 26.85 μg/cm2) calculated from LCD and LAI. The results indicated that the CCD of maize can be accurately estimated from multiple multispectral image features at the whole growth stage, and both CCD estimation strategies can be used to estimate the CCD accurately. This study provides a new reference for accurate CCD evaluation in precision agriculture

In-situ measurements of land-atmosphere exchanges of water energy and carbon dioxide in space and time over the heterogeneous Barrax site during SPARC2004

International audienceIn order to advance our understanding of land-atmosphere exchanges of water, energy and CO2 in space and time over heterogeneous land surfaces, an intensive field campaign was carried out at the Barrax agricultural test site in Spain in the period 12-21 July 2004 involving multiple field, satellite and airborne instruments for characterizing the state of the atmosphere, the vegetation and the soil from visible to microwave range of the spectrum. Part of the experimental area is a core site of a 25 km2 area within which numerous crops are grown - on both irrigated and dry land - alongside fields of bare soil. This campaign was carried out in combination with the EU 6FP EAGLE Project. Emphasis of this paper is on the in-situ measurements of land-atmosphere exchanges of water, energy and CO2 as well as the thermal dynamic states of the atmosphere, the soil and the vegetation

Impact of the coronavirus disease 2019 interventions on the incidence of hand, foot, and mouth disease in mainland China

Background: In early 2020, non-pharmaceutical interventions (NPIs) were implemented in China to reduce and contain the coronavirus disease 2019 (COVID-19) transmission. These NPIs might have also reduced the incidence of hand, foot, and mouth disease (HFMD). Methods: The weekly numbers of HFMD cases and meteorological factors in 31 provincial capital cities and municipalities in mainland China were obtained from Chinese Center for Disease Control and Prevention (CCDC) and National Meteorological Information Center of China from 2016 to 2020. The NPI data were collected from local CDCs. The incidence rate ratios (IRRs) were calculated for the entire year of 2020, and for January-July 2020 and August-December 2020. The expected case numbers were estimated using seasonal autoregressive integrated moving average models. The relationships between kindergarten closures and incidence of HFMD were quantified using a generalized additive model. The estimated associations from all cities were pooled using a multivariate meta-regression model. Findings: Stringent NPIs were widely implemented for COVID-19 control from January to July 2020, and the IRRs for HFMD were less than 1 in all 31 cities, and less than 0.1 for 23 cities. Overall, the proportion of HFMD cases reduced by 52.9% (95% CI: 49.3-55.5%) after the implementation of kindergarten closures in 2020, and this effect was generally consistent across subgroups. Interpretation: The decrease in HFMD incidence was strongly associated with the NPIs for COVID-19. HFMD epidemic peaks were either absent or delayed, and the final epidemic size was reduced. Kindergarten closure is an intervention to prevent HFMD outbreaks. Funding: This research was supported by the National Natural Science Foundation of China (81973102 & 81773487), Public Health Talents Training Program of Shanghai Municipality (GWV-10.2-XD21), the Shanghai New Three-year Action Plan for Public Health (GWV-10.1-XK16), the Major Project of Scientific and Technical Winter Olympics from National Key Research and Development Program of China (2021YFF0306000), 13th Five-Year National Science and Technology Major Project for Infectious Diseases (2018ZX10725-509) and Key projects of the PLA logistics Scientific research Program (BHJ17J013)