Chinese Soil Moisture Observation Network and Time Series Data Set for High Resolution Satellite Applications.

High-quality ground observation networks are an important basis for scientific research. Here, an automatic soil observation network for high-resolution satellite applications in China (SONTE-China) was established to measure both pixel- and multilayer-based soil moisture and temperature. SONTE-China is distributed across 17 field observation stations with a variety of ecosystems, covering both dry and wet zones. In this paper, the average root mean squared error (RMSE) of station-based soil moisture for well-characterized SONTE-China sites is 0.027 m3/m3 (0.014~0.057 m3/m3) following calibration for specific soil properties. The temporal and spatial characteristics of the observed soil moisture and temperature in SONTE-China conform to the geographical location, seasonality and rainfall of each station. The time series Sentinel-1 C-band radar signal and soil moisture show strong correlations, and the RMSE of the estimated soil moisture from radar data was lower than 0.05 m3/m3 for the Guyuan and Minqin stations. SONTE-China is a soil moisture retrieval algorithm that can validate soil moisture products and provide basic data for weather forecasting, flood forecasting, agricultural drought monitoring and water resource management.

Genome-wide analysis and molecular dissection of the SPL gene family in Fraxinus mandshurica.

BACKGROUND: SQUAMOSA promoter binding protein-like (SPL) is a unique family of transcription factors in plants, which is engaged in regulating plant growth and development, physiological and biochemical processes. Fraxinus mandshurica is an excellent timber species with a wide range of uses in northeastern China and enjoys a high reputation in the international market. SPL family analysis has been reported in some plants while SPL family analysis of Fraxinus mandshurica has not been reported. RESULTS: We used phylogeny, conserved motifs, gene structure, secondary structure prediction, miR156 binding sites, promoter cis elements and GO annotation to systematically analyze the FmSPLs family. This was followed by expression analysis by subcellular localization, expression patterns at various tissue sites, abiotic stress and hormone induction. Because FmSPL2 is highly expressed in flowers it was selected to describe the SPL gene family of Fraxinus mandshurica by ectopic expression. Among them, 10 FmSPL genes that were highly expressed at different loci were selected for expression analysis under abiotic stress (NaCl and Cold) and hormone induction (IAA and ABA). These 10 FmSPL genes showed corresponding trends in response to both abiotic stress and hormone induction. We showed that overexpression of FmSPL2 in transgenic Nicotiana tabacum L. resulted in taller plants, shorter root length, increased root number, rounded leaves, and earlier flowering time. CONCLUSIONS: We identified 36 SPL genes, which were classified into seven subfamilies based on sequence analysis. FmSPL2 was selected for subsequent heterologous expression by analysis of expression patterns in various tissues and under abiotic stress and hormone induction, and significant phenotypic changes were observed in the transgenic Nicotiana tabacum L. These results provide insight into the evolutionary origin and biological significance of plant SPL. The aim of this study was to lay the foundation for the genetic improvement of Fraxinus mandshurica and the subsequent functional analysis of FmSPL2.

Nondestructive Classification of Maize Moldy Seeds by Hyperspectral Imaging and Optimal Machine Learning Algorithms.

Mildew of maize seeds may affect their germination rates and reduce crop quality. It is crucial to classify maize seeds efficiently and without destroying their original structure. This study aimed to establish hyperspectral datasets using hyperspectral imaging (HSI) of maize seeds with different degrees of mildew and then classify them using spectral characteristics and machine learning algorithms. Initially, the images were processed with Otus and morphological operations. Each seed's spectral features were extracted based on its coding, its edge, region of interest (ROI), and original pixel coding. Random forest (RF) models were optimized using the sparrow search algorithm (SSA), which is incapable of escaping the local optimum; hence, it was optimized using a modified reverse sparrow search algorithm (JYSSA) strategy. This reverse strategy selects the top 10% as the elite group, allowing us to escape from local optima while simultaneously expanding the range of the sparrow search algorithm's optimal solution. Finally, the JYSSA-RF algorithm was applied to the validation set, with 96% classification accuracy, 100% precision, and a 93% recall rate. This study provides novel ideas for future nondestructive detection of seeds and moldy seed selection by combining hyperspectral imaging and JYSSA algorithms based on optimized RF.

Molecular cloning and functional analysis of a UV-B photoreceptor gene, BpUVR8 (UV Resistance Locus 8), from birch and its role in ABA response.

As a photoreceptor specifically for UV-B light, UVR8 gene plays an important role in the photomorphogenesis and developmental growth of plants. In this research, we isolated the UVR8 gene from birch, named BpUVR8 (AHY02156). BpUVR8 overexpression rescued the uvr8 mutant phenotype using functional complementation assay of BpUVR8 in Arabidopsis uvr8 mutants, which showed that the function of UVR8 is conserved between Arabidopsis and birch. The expression analysis of BpUVR8 indicated that this gene is expressed in various tissues, but its expression levels in leaves are higher than in other organs. Moreover, abiotic stress factors, such as UV-B, salinity, and abscisic acid (ABA) can induce the expression of BpUVR8 gene. Interestingly, the analysis of promoter activity indicated that BpUVR8 promoter not only has the promoting activity but can also respond to the induction of abiotic stress and ABA signal. So, we analyzed its function in ABA response via transgenic UVR8 overexpression in Arabidopsis. The BpUVR8 enhances the susceptibility to ABA, which indicates that BpUVR8 is regulated by ABA and can inhibit seed germination. The root length of 20-day-old 35S::BpUVR8/WT transgenic plants was 18% reduced as compared to the wild-type under the ABA treatment. The membrane of the BpUVR8-overexpressing in Arabidopsis thaliana was the most damaged after ABA treatment and 35S::BpUVR8/WT transgenic plant was more sensitive to ABA than the wild type. These results showed that BpUVR8 is a positive regulator in the ABA signal transduction pathway. In the presence of low dose of UV-B, the sensitivity of wild-type and 35S::BpUVR8/WT plants to ABA was reduced. Moreover, BpUVR8 regulates the expression of a subset of ABA-responsive genes, both in Arabidopsis and Betula platyphylla, under the ABA treatment. Our data provide evidence that BpUVR8 is a positive regulator in the UV-B-induced photomorphogenesis in plants. Moreover, we propose from this research that BpUVR8 might have an important role in integrating plant growth and ABA signaling pathway.