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Background Cotton fiber is a model system for studying plant cell development. At present, the functions of many transcription factors in cotton fiber development have been elucidated, however, the roles of auxin response factor (ARF) genes in cotton fiber development need be further explored. Results Here, we identify auxin response factor (ARF) genes in three cotton species: the tetraploid upland cotton G. hirsutum , which has 73 ARF genes, and its putative extent parental diploids G. arboreum and G. raimondii , which have 36 and 35 ARFs, respectively. Ka and Ks analyses revealed that in G. hirsutum ARF genes have undergone asymmetric evolution in the two subgenomes. The cotton ARFs can be classified into four phylogenetic clades and are actively expressed in young tissues. We demonstrate that GhARF2b , a homolog of the Arabidopsis AtARF2 , was preferentially expressed in developing ovules and fibers. Overexpression of GhARF2b by a fiber specific promoter inhibited fiber cell elongation but promoted initiation and, conversely, its downregulation by RNAi resulted in fewer but longer fiber. We show that GhARF2b directly interacts with GhHOX3 and represses the transcriptional activity of GhHOX3 on target genes. Conclusion Our results uncover an important role of the ARF factor in modulating cotton fiber development at the early stage.

Background The cryptochromes (CRY) are specific blue light receptors of plants and animals, which play crucial roles in physiological processes of plant growth, development, and stress tolerance. Results In the present work, a systematic analysis of the CRY gene family was performed on twelve cotton species, resulting in 18, 17, 17, 17, and 17 CRYs identified in five alloteraploid cottons ( Gossypium hirsutum , G. barbadense , G. tomentosum , G. mustelinum and G. darwinii ), respectively, and five to nine CRY genes in the seven diploid species. Phylogenetic analysis of protein-coding sequences revealed that CRY genes from cottons and Arabidopsis thaliana could be classified into seven clades. Synteny analysis suggested that the homoeolog of G. hirsutum Gh_A02G0384 has undergone an evolutionary loss event in the other four allotetraploid cotton species. Cis -element analysis predicated the possible functions of CRY genes in G. hirsutum . RNA-seq data revealed that Gh_D09G2225 , Gh_A09G2012 and Gh_A11G1040 had high expressions in fiber cells of different developmental states. In addition, the expression levels of one ( Gh_A03G0120 ), 15 and nine GhCRY genes were down-regulated following the PEG, NaCl and high-temperature treatments, respectively. For the low-temperature treatment, five GhCRY genes were induced, and five were repressed. These results indicated that most GhCRY genes negatively regulate the abiotic stress treatments. Conclusion We report the structures, domains, divergence, synteny, and cis -elements analyses systematically of G. hirsutum CRY genes. Possible biological functions of GhCRY genes in differential tissues as well as in response to abiotic stress during the cotton plant life cycle were predicted.

N6-methyladenosine (m6A) RNA modification plays important regulatory roles in plant development and adapting to the environment, which requires methyltransferases to achieve the methylation process. However, there has been no research regarding m6A RNA methyltransferases in cotton. Here, a systematic analysis of the m6A methyltransferase (METTL) gene family was performed on twelve cotton species, resulting in six METTLs identified in five allotetraploid cottons, respectively, and three to four METTLs in the seven diploid species. Phylogenetic analysis of protein-coding sequences revealed that METTL genes from cottons, Arabidopsis thaliana, and Homo sapiens could be classified into three clades (METTL3, METTL14, and METTL-like clades). Cis-element analysis predicated the possible functions of METTL genes in G. hirsutum. RNA-seq data revealed that GhMETTL14 (GH_A07G0817/GH_D07G0819) and GhMETTL3 (GH_A12G2586/GH_D12G2605) had high expressions in root, stem, leaf, torus, petal, stamen, pistil, and calycle tissues. GhMETTL14 also had the highest expression in 20 and 25 dpa fiber cells, implying a potential role at the cell wall thickening stage. Suppressing GhMETTL3 and GhMETTL14 by VIGS caused growth arrest and even death in G. hirsutum, along with decreased m6A abundance from the leaf tissues of VIGS plants. Overexpression of GhMETTL3 and GhMETTL14 produced distinct differentially expressed genes (DEGs) in A. thaliana, indicating their possible divergent functions after gene duplication. Overall, GhMETTLs play indispensable but divergent roles during the growth of cotton plants, which provides the basis for the systematic investigation of m6A in subsequent studies to improve the agronomic traits in cotton.

N6-methyladenosine (m6A) RNA modification plays important regulatory roles in plant development and adapting to the environment, which requires methyltransferases to achieve the methylation process. However, there has been no research regarding m6A RNA methyltransferases in cotton. Here, a systematic analysis of the m6A methyltransferase (METTL) gene family was performed on twelve cotton species, resulting in six METTLs identified in five allotetraploid cottons, respectively, and three to four METTLs in the seven diploid species. Phylogenetic analysis of protein-coding sequences revealed that METTL genes from cottons, Arabidopsis thaliana, and Homo sapiens could be classified into three clades (METTL3, METTL14, and METTL-like clades). Cis-element analysis predicated the possible functions of METTL genes in G. hirsutum. RNA-seq data revealed that GhMETTL14 (GH_A07G0817/GH_D07G0819) and GhMETTL3 (GH_A12G2586/GH_D12G2605) had high expressions in root, stem, leaf, torus, petal, stamen, pistil, and calycle tissues. GhMETTL14 also had the highest expression in 20 and 25 dpa fiber cells, implying a potential role at the cell wall thickening stage. Suppressing GhMETTL3 and GhMETTL14 by VIGS caused growth arrest and even death in G. hirsutum, along with decreased m6A abundance from the leaf tissues of VIGS plants. Overexpression of GhMETTL3 and GhMETTL14 produced distinct differentially expressed genes (DEGs) in A. thaliana, indicating their possible divergent functions after gene duplication. Overall, GhMETTLs play indispensable but divergent roles during the growth of cotton plants, which provides the basis for the systematic investigation of m6A in subsequent studies to improve the agronomic traits in cotton.

Background: The cryptochromes (CRY) comprise a specific blue light receptor for plants and animals, which play crucial roles in physiological processes of plant growth, development, and stress tolerance. Results: In the present work, a systematical analysis of CRY gene family from five allotetraploid cotton species, G. hirsutum, G. barbadense, G. tomentosum, G. mustelinum and G. darwinii together with seven diploid species. There were 18, 17, 17, 17, and 17 CRYs identified in G. hirsutum, G. barbadense, G. tomentosum, G. mustelinum and G. darwinii, respectively, whereas five to nine CRY genes were identified in the diploid species. Phylogenetic analysis of the protein-coding sequences revealed that CRY genes from the allotetraploids G. hirsutum and G. barbadense, three diploid cotton species (G. raimondii, G. herbaceum, and G. arboreum), and Arabidopsis thaliana could be classified into seven clades. Synteny analysis suggested that the homoeolog of G. hirsutum Gh_A02G0384 has undergone an evolutionary loss event in the other four allotetraploid cotton species. Cis-element analysis predicated the possible functions of CRY genes in G. hirsutum. Public RNA-seq data were investigated to analyze the expression patterns of G. hirsutum CRY genes in various tissues as well as gene expressions under abiotic stress treatments. Conclusion: These results indicated the possible functions of G. hirsutum CRY genes in differential tissues as well as in response to abiotic stress during the cotton plants life cycle.

Background: Cotton fiber is a model system for studying plant cell development. At present, our understanding of cotton fiber development and the regulatory network is still primitive. Results: Here, we identify auxin response factor (ARF) genes in three cotton species: the tetraploid upland cotton G. hirsutum, which has 73 ARF genes, and its putative extent parental diploids G. arboreum and G. raimondii, which have 36 and 35 ARFs, respectively. Ka and Ks analyses revealed that in G. hirsutum ARF genes have undergone asymmetric evolution in the two subgenomes. The cotton ARFs can be classified into four phylogenetic clades and are actively expressed in young tissues. We demonstrate that GhARF2b, a homolog of the Arabidopsis AtARF2, was preferentially expressed in developing ovules and fibers. Overexpression of GhARF2b by a fiber specific promoter inhibited fiber cell elongation but promoted initiation and, conversely, its downregulation by RNAi of resulted in fewer but longer fiber. Conclusion: Our results uncover an important role of the ARF factor in modulating cotton fiber development at the early stage.

H 2 O 2 photosynthesis represents an appealing approach for sustainable and decentralized H 2 O 2 production. Unfortunately, current reactions are mostly carried out in laboratory-scale single-phase batch reactors, which have a limited H 2 O 2 production rate (<100 μmol h −1 ) and cannot operate in an uninterrupted manner. Herein, we propose continuous H 2 O 2 photosynthesis and extraction in a biphasic fluid system. A superhydrophobic covalent organic framework photocatalyst with perfluoroalkyl functionalization is rationally designed and prepared via the Schiff-base reaction. When applied in a home-built biphasic fluid photo-reactor, the superhydrophobicity of our photocatalyst allows its selective dispersion in the oil phase, while formed H 2 O 2 is spontaneously extracted to the water phase. Through optimizing reaction parameters, we achieve continuous H 2 O 2 photosynthesis and extraction with an unprecedented production rate of up to 968 μmol h −1 and tunable H 2 O 2 concentrations from 2.2 to 38.1 mM. As-obtained H 2 O 2 solution could satisfactorily meet the general demands of household disinfection and wastewater treatments. Photocatalytic H 2 O 2 synthesis is often performed in lab-scale batch reactors with low efficiency. Here, the authors report a biphasic fluid system that enables continuous H 2 O 2 synthesis and automatic product extraction, addressing the limitations of traditional methods.

This work focuses on transient forced vibration response characteristics of a radial turbine passing through the resonant frequency at different speeds. The transient structure analysis based on the modal superposition method is used to calculate the vibration response of the impeller, and the frequency sweep tests are carried out to verify the calculation results. The experimental results are in good agreement with the simulation results. The impeller response curve becomes steeper as the frequency sweep time increases; however, the elastic potential energy of the blade is dissipated more by the structural damping at 13000 Hz. The response waveform of frequency sweep time 10s is close to the situation of 60s. When the frequency sweep takes the 60s, the excitation energy is input to the impeller, and the damping dissipation of the system reaches a state close to equilibrium.

Enhancers act to regulate cell-type-specific gene expression by facilitating the transcription of target genes. In mammalian cells, active or primed enhancers are commonly marked by monomethylation of histone H3 at lysine 4 (H3K4me1) in a cell-type-specific manner. Whether and how this histone modification regulates enhancer-dependent transcription programs in mammals is unclear. In this study, we conducted SILAC mass spectrometry experiments with mononucleosomes and identified multiple H3K4me1-associated proteins, including many involved in chromatin remodeling. We demonstrate that H3K4me1 augments association of the chromatin-remodeling complex BAF to enhancers in vivo and that, in vitro, H3K4me1-marked nucleosomes are more efficiently remodeled by the BAF complex. Crystal structures of the BAF component BAF45C indicate that monomethylation, but not trimethylation, is accommodated by BAF45C’s H3K4-binding site. Our results suggest that H3K4me1 has an active role at enhancers by facilitating binding of the BAF complex and possibly other chromatin regulators. The authors conduct mass spectrometry experiments identifying H3K4me1-associated proteins, including members of the BAF chromatin-remodeling complex. They show that H3K4me1 augments association of the BAF complex with enhancers in vivo and that H3K4me1-marked nucleosomes are more efficiently remodeled by the BAF complex in vitro.

As a typical visual foundation model, SAM has been extensively utilized for optical image segmentation tasks. However, synthetic aperture radar (SAR) employs a unique imaging mechanism, and its images are very different from optical images. Directly transferring a pretrained SAM from optical scenes to SAR image instance segmentation tasks can lead to a substantial decline in performance. Therefore, this paper fully integrates the SAR scattering mechanism, and proposes a SAR image target segmentation method guided by the SAR scattering mechanism-based visual foundation model. First, considering the discrete distribution features of strong scattering points in SAR imagery, we develop an edge enhancement morphological adaptor. This adaptor is designed to incorporate a limited set of trainable parameters aimed at effectively boosting the target’s edge morphology, allowing quick fine-tuning within the SAR realm. Second, an adaptive denoising module based on wavelets and soft-thresholding techniques is implemented to reduce the impact of SAR coherent speckle noise, thus improving the feature representation performance. Furthermore, an efficient automatic prompt module based on a deep object detector is built to enhance the ability of rapid target localization in wide-area scenes and improve image segmentation performance. Our approach has been shown to outperform current segmentation methods through experiments conducted on two open-source datasets, SSDD and HRSID. When the ground-truth is used as a prompt, SARSAM improves mIOU by more than 10%, and APmask50 by more than 5% from the baseline. In addition, the computational cost is greatly reduced because the number of parameters and FLOPs of the structures that require fine-tuning are only 13.5% and 10.1% of the baseline, respectively.