E3 ligase DECREASED GRAIN SIZE 1 promotes degradation of a G-protein subunit and positively regulates grain size in rice.

Grain size is one of the most important traits determining crop yield. However, the mechanism controlling grain size remains unclear. Here, we confirmed the E3 ligase activity of DECREASED GRAIN SIZE 1 (DGS1) in positive regulation of grain size in rice (Oryza sativa) suggested in a previous study. Rice G-protein subunit gamma 2 (RGG2), which negatively regulates grain size, was identified as an interacting protein of DGS1. Biochemical analysis suggested that DGS1 specifically interacts with canonical Gγ subunits (rice G-protein subunit gamma 1 [RGG1] and rice G-protein subunit gamma 2 [RGG2]) rather than non-canonical Gγ subunits (DENSE AND ERECT PANICLE 1 [DEP1], rice G-protein gamma subunit type C 2 [GCC2], GRAIN SIZE 3 [GS3]). We also identified the necessary domains for interaction between DGS1 and RGG2. As an E3 ligase, DGS1 ubiquitinated and degraded RGG2 via a proteasome pathway in several experiments. DGS1 also ubiquitinated RGG2 by its K140, K145 and S147 residues. Thus, this work identified a substrate of the E3 ligase DGS1 and elucidated the post transcriptional regulatory mechanism of the G-protein signalling pathway in the control of grain size.

Improving pre-harvest sprouting resistance in rice by editing OsABA8ox using CRISPR/Cas9.

KEY MESSAGE: Knock out OsABA8ox helps improve pre-harvest spouting resistance and do not affect rice yield. Pre-harvest sprouting(PHS) is a phenomenon that the seeds of crops germinate preharvest, which reduces the yield and quality of rice. Abscisic acid(ABA) is one of the phytohormones that promotes seed dormancy. ABA8' hydroxylase is the main enzyme that can catabolism ABA in plant. There are three genes that encode ABA8' hydroxylase in rice, named OsABA8ox1, OsABA8ox2 and OsABA8ox3. In this study, we use CRISPR/Cas9 gene editing technology to target these three genes in Ningjing6 and find that the knockout transgenic lines are all significantly strengthen in seed dormancy and have no effect on the yield. By a series of quantitative experiments, we consider that after knock out OsABA8ox, the high endogenous ABA level will influence the ABA signal which suppress the substantial and energy metabolism in the seeds, and finally led to higher dormancy.

Ribonuclease H-like gene SMALL GRAIN2 regulates grain size in rice through brassinosteroid signaling pathway.

Grain size is a key agronomic trait that determines the yield in plants. Regulation of grain size by brassinosteroids (BRs) in rice has been widely reported. However, the relationship between the BR signaling pathway and grain size still requires further study. Here, we isolated a rice mutant, named small grain2 (sg2), which displayed smaller grain and a semi-dwarf phenotype. The decreased grain size was caused by repressed cell expansion in spikelet hulls of the sg2 mutant. Using map-based cloning combined with a MutMap approach, we cloned SG2, which encodes a plant-specific protein with a ribonuclease H-like domain. SG2 is a positive regulator downstream of GLYCOGEN SYNTHASE KINASE2 (GSK2) in response to BR signaling, and its mutation causes insensitivity to exogenous BR treatment. Genetical and biochemical analysis showed that GSK2 interacts with and phosphorylates SG2. We further found that BRs enhance the accumulation of SG2 in the nucleus, and subcellular distribution of SG2 is regulated by GSK2 kinase activity. In addition, Oryza sativa OVATE family protein 19 (OsOFP19), a negative regulator of grain shape, interacts with SG2 and plays an antagonistic role with SG2 in controlling gene expression and grain size. Our results indicated that SG2 is a new component of GSK2-related BR signaling response and regulates grain size by interacting with OsOFP19.

Decreased grain size1, a C3HC4-type RING protein, influences grain size in rice (Oryza sativa L.).

KEY MESSAGE: We reported that DGS1 plays a positive role in regulating grain size in rice and was regulated by OsBZR1. Grain size is an important agronomic trait that contributes to grain yield. However, the underlying molecular mechanisms that determine final grain size are still largely unknown. We isolated a rice mutant showing reduced grain size in a 60Co-irradiated variety Nanjing 35 population. We named the mutant decreased grain size1 (dgs1). Map-based cloning and subsequent transgenic CRISPR and complementation assays indicated that a mutation had occurred in LOC_Os03g49900 and that the DGS1 allele regulated grain size. DGS1 encodes a protein with a 7-transmembrane domain and C3HC4 type RING domain. It was widely expressed, especially in young tissues. DGS1 is a membrane-located protein. OsBZR1 (BRASSINAZOLE-RESISTANT1), a core transcription activator of BR signaling, also plays a positive role in grain size. We provided preliminary evidence that OsBZR1 can bind to the DGS1 promoter to activate expression of DGS1.

Invariant Image Representation Using Novel Fractional-Order Polar Harmonic Fourier Moments.

Continuous orthogonal moments, for which continuous functions are used as kernel functions, are invariant to rotation and scaling, and they have been greatly developed over the recent years. Among continuous orthogonal moments, polar harmonic Fourier moments (PHFMs) have superior performance and strong image description ability. In order to improve the performance of PHFMs in noise resistance and image reconstruction, PHFMs, which can only take integer numbers, are extended to fractional-order polar harmonic Fourier moments (FrPHFMs) in this paper. Firstly, the radial polynomials of integer-order PHFMs are modified to obtain fractional-order radial polynomials, and FrPHFMs are constructed based on the fractional-order radial polynomials; subsequently, the strong reconstruction ability, orthogonality, and geometric invariance of the proposed FrPHFMs are proven; and, finally, the performance of the proposed FrPHFMs is compared with that of integer-order PHFMs, fractional-order radial harmonic Fourier moments (FrRHFMs), fractional-order polar harmonic transforms (FrPHTs), and fractional-order Zernike moments (FrZMs). The experimental results show that the FrPHFMs constructed in this paper are superior to integer-order PHFMs and other fractional-order continuous orthogonal moments in terms of performance in image reconstruction and object recognition, as well as that the proposed FrPHFMs have strong image description ability and good stability.

UGEE-Net: Uncertainty-guided and edge-enhanced network for image splicing localization.

Image splicing, a prevalent method for image tampering, has significantly undermined image authenticity. Existing methods for Image Splicing Localization (ISL) struggle with challenges like limited accuracy and subpar performance when dealing with imperceptible tampering and multiple tampered regions. We introduce an Uncertainty-Guided and Edge-Enhanced Network (UGEE-Net) for ISL to tackle these issues. UGEE-Net consists of two core tasks: uncertainty guidance and edge enhancement. We employ Bayesian learning to model uncertainty maps of tampered regions, directing the model's focus to challenging pixels. Simultaneously, we employ a frequency domain-auxiliary edge enhancement strategy to imbue localization features with global contour information and fine-grained local details. These mechanisms work in parallel, synergistically boosting performance. Additionally, we introduce a cross-level fusion and propagation mechanism that effectively utilizes contextual information for cross-layer feature integration and leverages channel-level correlations for cross-layer feature propagation, gradually enhancing the localization feature's details. Experiment results affirm UGEE-Net's superiority in terms of detection accuracy, robustness, and generalization capabilities. Furthermore, to meet the growing demand for high-quality datasets in image forensics, we present the HTSI12K dataset, which includes 12,000 spliced images with imperceptible tampering traces and diverse categories, rendering it suitable for real-world auxiliary model training.

WEAK SEED DORMANCY 1, an aminotransferase protein, regulates seed dormancy in rice through the GA and ABA pathways.

Seed dormancy is a critical trait that enhances plant survival by preventing seed germination at the wrong time or under unsuitable conditions. Lack of seed dormancy in rice can lead to pre-harvest sprouting on mother plants leading to reduced yield and seed quality. Although some genes have been identified, knowledge of regulation of seed dormancy is limited. Here, we characterized a weak seed dormancy mutant named weak seed dormancy 1 (wsd1) that showed a higher seed germination percentage than the wild-type following the harvest ripeness. We cloned the WSD1 encoding an aminotransferase protein using a MutMap approach. WSD1 was stably expressed after imbibition and its protein was localized in the endoplasm reticulum. A widely targeted metabolomics assay and amino acid analysis showed that WSD1 had a role in regulating homeostasis of amino acids. PAC treatment and RNA-seq analysis showed that WSD1 regulates seed dormancy by involvement in the GA biosynthesis pathway. GA1 content and expression of GA biosynthesis-related genes were increased in the wsd1 mutant compared with the wild-type. The wsd1 mutant had reduced sensitivity to ABA. Our overall results indicated that WSD1 regulates seed dormancy by balancing the ABA and GA pathways.

Comparative Transcriptome Profiling Reveals the Genes Involved in Storage Root Expansion in Sweetpotato (Ipomoea batatas (L.) Lam.).

Sweetpotato (Ipomoea batatas (L.) Lam.) is recognized as one of the most important root crops in the world by the Food and Agriculture Organization of the United Nations. The yield of sweetpotato is closely correlated with the rate of storage root (SR) formation and expansion. At present, most of the studies on sweetpotato SR expansion are focused on the physiological mechanism. To explore the SR expansion mechanism of sweetpotato, we performed transcriptome sequencing of SR harvested at 60, 90, 120, and 150 days after planting (DAP) to analyze two sweetpotato lines, Xuzishu 8 and its crossing progenies named Xu 18-192, which were selected from an F1 segregation population of Xuzishu 8 and Meiguohong, in which SR expansion was delayed significantly. A total of 57,043 genes were produced using transcriptome sequencing, of which 1312 were differentially expressed genes (DEGs) in four SR growth periods of the sweetpotato lines. The combination of the KEGG and trend analysis revealed several key candidate genes involved in SR expansion. The SBEI gene involved in starch metabolism, and transcription factors ARF6, NF-YB3 and NF-YB10 were all significantly up-regulated during SR expansion. The data from this study provide insights into the complex mechanisms of SR formation and expansion in sweetpotato and identify new candidate genes for increasing the yield of sweetpotato.

Rice OsBT1 regulates seed dormancy through the glycometabolism pathway.

Seed dormancy and germination in rice (Oryza sativa L.) are complex and important agronomic traits that involve a number of physiological processes and energy. A mutant named h470 selected from a60Co-radiated indica cultivar N22 population had weakened dormancy that was insensitive to Gibberellin (GA) and Abscisic acid (ABA). The levels of GA4 and ABA were higher in h470 than in wild-type (WT) plants. The gene controlling seed dormancy in h470 was cloned by mut-map and transgenesis and confirmed to encode an ADP-glucose transporter protein. A 1 bp deletion in Os02g0202400 (OsBT1) caused the weaker seed dormancy in h470. Metabolomics analyses showed that most sugar components were higher in h470 seeds than the wild type. The mutation in h470 affected glycometabolism.