Search bioRxiv⌕ Search

Biology subjects

Zhang, S.

Publications and source records attributed to Zhang, S..

At least 775 records · Page 43Linked to original sources

Universal mechanism of hormone and allosteric agonist mediated activation of glycoprotein hormone receptors as revealed by structures of follicle stimulating hormone receptor

Follicle stimulating hormone (FSH) is an essential glycoprotein hormone for human reproduction, which functions are mediated by a G protein-coupled receptor, FSHR. Aberrant FSH-FSHR signaling causes infertility and ovarian hyperstimulation syndrome. Here we report cryo-EM structures of FSHR in both inactive and active states, with the active structure bound to FSH and an allosteric agonist compound 21f. The structures of FSHR are similar to other glycoprotein hormone receptors, highlighting a conserved activation mechanism of hormone-induced receptor activation. Compound 21f formed extensive interactions with the TMD to directly activate FSHR. Importantly, the unique residue H6157.42 in FSHR plays an essential role in determining FSHR selectivity for various allosteric agonists. Together, our structures provide a molecular basis of FSH and small allosteric agonist-mediated FSHR activation, which could inspire the design of FSHR-targeted drugs for the treatment of infertility and controlled ovarian stimulation for in vitro fertilization.

cell biology↗

Fat Extract Modulates Calcium Signaling and Protects Against Hyperactive Osteoclastogenesis in Bone Remodeling with Antioxidant Capacity

Osteoclasts are cells which are primarily involved in bone remodeling and osteolytic bone diseases. Hyperactive osteoclastogenesis leads to pathological bone loss and microarchitectural deterioration, particularly in postmenopausal osteoporosis. However, given the limitations of current first-line osteoclast inhibitors, there is an urgent need for a novel antiresorptive agent with higher efficiency and fewer side effects. Cell-free fat extract (CEFFE) is the liquid fraction obtained from human adipose tissues, which are enriched with a variety of cytokines and growth factors. This study aims to explore its pharmaceutical effect on hyperactive osteoclast formation in vivo and in vitro. CEFFE exhibits excellent potentials to attenuate osteoclast-associated bone loss in an ovariectomy (OVX) mouse model and to inhibit RANKL-induced osteoclastogenesis in primary bone marrow-derived monocytes. Furthermore, the cationic protein fraction of CEFFE (CEFFE-Cation) is identified as the main inhibitory component in osteoclast formation assay. Excessive reactive oxygen species (ROS) production is the main cause of osteoclast overactivation. According to LC-MS/MS analysis, the CEFFE-Cation fraction mainly consists of various antioxidant enzymes, extracellular matrix, and secreted cytokines, which endow it with a superior antioxidant capacity. Ca2+ signaling contributes to osteoclast maturation. In addition to scavenging ROS, CEFFE-Cation is also capable of mitigating Ca2+ oscillation, calcineurin activation, and subsequent NFATc1 nuclear translocation during osteoclastogenesis. Overall, this study elucidates the promising translational potential of CEFFE as a next-generation personalized antiresorptive agent for osteolytic bone disease treatment.

pathology↗

Inference of cell type-specific gene regulatory networks on cell lineages from single cell omic datasets

Cell type-specific gene expression patterns are outputs of transcriptional gene regulatory networks (GRNs) that connect transcription factors and signaling proteins to target genes. Single-cell technologies such as single cell RNA-sequencing (scRNA-seq) and single cell Assay for Transposase-Accessible Chromatin using sequencing (scATAC-seq), can examine cell-type specific gene regulation at unprecedented detail. However, current approaches to infer cell type-specific GRNs are limited in their ability to integrate scRNA-seq and scATAC-seq measurements and to model network dynamics on a cell lineage. To address this challenge, we have developed single-cell Multi-Task Network Inference (scMTNI), a multi-task learning framework to infer the GRN for each cell type on a lineage from scRNA-seq and scATAC-seq data. Using simulated and real datasets, we show that scMTNI is a broadly applicable framework for linear and branching lineages that accurately infers GRN dynamics and identifies key regulators of fate transitions for diverse processes such as cellular reprogramming and differentiation.

bioinformatics↗

Multimodal electrocorticogram active electrode array based on zinc oxide-thin film transistors

Active electrocorticogram (ECoG) electrodes can amplify the weak electrophysiological signals and improve the anti-interference ability, but the traditional active electrodes are so opaque that cannot realize photoelectric collaborative observation. Here an active and fully-transparent ECoG array based on zinc oxide-thin film transistors (ZnO-TFTs) was developed as the local neural signal amplifier for electrophysiological monitoring. The transparency of the proposed ECoG array was up to 85% which is superior to previous reported active electrode array. Various electrical characterizations demonstrated its ability of electrophysiological signal recording, with a higher signal-to-noise ratio of 19.9 dB compared to the Au grid one (13.2 dB). The high transparency of ZnO-TFT electrode array allowed the collecting electrophysiological signals under direct light stimulation on optogenetic mice brain concurrently. The ECoG array could also work under 7-Tesla magnetic resonance imaging to record local brain signal without affecting brain tissue imaging. As the most transparent active ECoG array to date, it provides a powerful multimodal tool for brain observation, including recording brain activity under synchronized optical modulation and 7-Tesla magnetic resonance imaging.

bioengineering↗

Deep generative modeling and clustering of single cell Hi-C data

Deciphering 3D genome conformation is important for understanding gene regulation and cellular function at a spatial level. The recent advances of single cell Hi-C technologies have enabled the profiling of the 3D architecture of DNA within individual cell, which allows us to study the cell-to-cell variability of 3D chromatin organization. Computational approaches are in urgent need to comprehensively analyze the sparse and heterogeneous single cell Hi-C data. Here, we proposed scDEC-Hi-C, a new framework for single cell Hi-C analysis with deep generative neural networks. scDEC-Hi-C outperforms existing methods in terms of single cell Hi-C data clustering and imputation. Moreover, the generative power of scDEC-Hi-C could help unveil the heterogeneity of chromatin architecture across different cell types. We expect that scDEC-Hi-C could shed light on deepening our understanding of the complex mechanism underlying the formation of chromatin contacts. scDEC-Hi-C is freely available at https://github.com/kimmo1019/scDEC-Hi-C. Key pointsO_LIscDEC-Hi-C provides an end-to-end framework based on autoencoder and deep generative model to comprehensively analyze single cell Hi-C data, including low-dimensional embedding and clustering. C_LIO_LIThrough a series of experiments including single cell Hi-C data clustering and structural difference identification, scDEC-Hi-C demonstrates suprioir performance over existing methods. C_LIO_LIIn the downstream analysis of chromatin loops from single cell Hi-C data, scDEC-Hi-C is capable of significantly enhancing the ability for identifying single cell chromatin loops by data imputation. C_LI

bioinformatics↗

Comprehensive analysis identifies histone 2A ubiquitination as a marker for aging and pan-cancer prognosis

Ubiquitination is a post-translational modification (PTM) that induces protein degradation or function alteration and plays crucial roles in aging and cancer. Previous ubiquitinomes of aging mainly focused on how ubiquitination changes in drosophila and other lower animals, but how ubiquitination changes during the aging of higher animals and what causes these changes remain unclear. Here, we profiled whole-life ubiquitinome data of mouse brain, heart, liver, muscle, and spleen, and integratively analyzed the ubiquitinome data with RNA sequencing data. The results showed that the ubiquitination of protein, especially histone 2A (H2A), changed intensely during aging due to the regulated expression of E3 ligases (E3s) and deubiquitylating enzymes (DUBs). Then we developed two distinct H2A E3s/DUBs expression subtypes with different prognosis, DNA damage response (DDR), and tumor microenvironment cell infiltration degrees based on an unsupervised method in pan-cancer. In conclusion, our study provided temporal resolution ubiquitinome data of mouse aging and revealed the vital role of H2A ubiquitination in aging and tumor progression.

cancer biology↗

MINE is a method for detecting spatial density of regulatory chromatin interactions based on a MultI-modal NEtwork

Chromatin interactions play essential roles in chromatin conformation and gene expression. However, few tools exist to analyze the spatial density of regulatory chromatin interactions. Here, we present the MultI-modal NEtwork (MINE) toolkit, including MINE-Loop, MINE-Density, and MINE-Viewer. MINE-Loop network modeling integrates Hi-C, ATAC-seq, and histone ChIP-seq data to enhance the detection of regulatory chromatin interactions (RCIs, i.e., chromatin interactions that are anchoring regulatory elements to chromatin); MINE-Density quantifies the spatial density of regulatory chromatin interactions identified by MINE-Loop within different chromatin conformations; and MINE-Viewer facilitates 3D visualization of the density of chromatin interactions and participating regulatory factors, such as transcription factors. We applied MINE to investigate the relationship between the spatial density of regulatory chromatin interactions (SD-RCI) and chromatin volume change in HeLa cells before and after liquid-liquid phase separation. Changes in SD-RCI before and after treating the HeLa cells with 1,6-hexanediol showed that the change in chromatin volume was related to the degree of activation or repression of genes in chromatin interactions. The MINE toolkit provides a new method for quantitative study of chromatin conformation. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=187 HEIGHT=200 SRC="FIGDIR/small/499656v1_ufig1.gif" ALT="Figure 1"> View larger version (51K): org.highwire.dtl.DTLVardef@1705cc8org.highwire.dtl.DTLVardef@1db89adorg.highwire.dtl.DTLVardef@2be8e4org.highwire.dtl.DTLVardef@c6f1a6_HPS_FORMAT_FIGEXP M_FIG C_FIG In BriefGong et al. provide a toolkit MINE to explore the relationship between spatial density of regulatory chromatin interactions, gene expression and chromatin structure change. HighlightsO_LIMINE toolkit was provided to detect more regulatory chromatin interactions (RCI), count the spatial density of regulatory chromatin interactions and visualize the density of chromatin interactions with transcription factors in three-dimension. C_LIO_LIChromatin regions were divided into developed active hub, developing active hub, developed repressive hub, and developing repressive hub according to the density of active or repressive regulatory chromatin interactions. C_LIO_LIThe change of chromatin structure before and after liquid-liquid phase separation is quantitively described by using the MINE toolkit. C_LI

bioinformatics↗

Human iPSC-derived neuron of 16p11.2 deletion reveals haplotype-specific expression of MAPK3 and its contribution to variable NDD phenotypes

Recurrent proximal 16p11.2 deletion (16p11.2del) is risk factor of diverse neurodevelopmental disorders (NDDs) with variable penetrance. Although previous human induced pluripotent stem cell (hiPSC) models of 16p11.2del confirmed disrupted neuron development, it is not known which gene(s) at this interval are mainly responsible for the abnormal cellular phenotypes and how the NDD penetrance is regulated. After haplotype phasing of 16p11.2 region, we generated hiPSCs for two 16p11.2del families with distinct residual haplotypes and variable NDD phenotypes. We also differentiated the hiPSCs to cortical neural cells and demonstrated MAPK3 as a driver signal of 16p11.2 region contributing to the dysfunctions in multiple pathways related to neuron development, which leads to altered morphological or electrophysiological properties in neuron cells. Furthermore, residual haplotype-specific MAPK3 expression was identified in 16p11.2del neuron cells, associating MAPK3 down-expression with the minor allele of the residual haplotype. Ten SNPs of the residual haplotype are mapped as enhancer SNPs (enSNPs) of MAPK3, eight enSNPs were functionally validated by luciferase assays, implying enSNPs contribute to residual haplotype-specific MAPK3 expression via cis-regulation. Finally, the analyses of three different patient cohorts showed that the residual haplotype of 16p11.2del is associated with variable NDD phenotypes.

genetics↗

A novel RHH family transcription factor aCcr1 and its viral homologs dictate cell cycle progression in archaea

Cell cycle regulation is of paramount importance for all forms of life. Here we report that a conserved and essential cell cycle-specific transcription factor (designated as aCcr1) and its viral homologs control cell division in Sulfolobales. We show that the transcription level of accr1 reaches peak during active cell division (D-phase) subsequent to the expression of CdvA, an archaea-specific cell division protein. Cells over-expressing the 58-aa-long RHH (ribbon-helix-helix) family cellular transcription factor as well as the homologs encoded by large spindle-shaped viruses Acidianus two-tailed virus (ATV) and Sulfolobus monocaudavirus 3 (SMV3) display significant growth retardation and cell division failure, manifested as enlarged cells with multiple chromosomes. aCcr1 over-expression results in downregulation of 17 genes (>4-folds) including cdvA. A conserved motif, aCcr1-box, located between the TATA-binding box and the translation initiation site in the promoters of 13 out of the 17 highly repressed genes, is critical for aCcr1 binding. The aCcr1-box is present in the promoters of cdvA genes across Sulfolobales, suggesting that aCcr1-mediated cdvA repression is an evolutionarily conserved mechanism by which archaeal cells dictate cytokinesis progression, whereas their viruses take advantage of this mechanism to manipulate the host cell cycle.

microbiology↗

Bioorthogonal in-cell Labeling and Profiling of N6-isopentenyladenosine (i6A) Modified RNA

Chemical modifications in RNAs play critical roles in structural diversification and functional regulation of many vital biochemical processes. Several hydrophobic prenyl-modifications have been discovered in a variety of RNA species since the 1990s. Prenyl groups are the feedstocks of terpene and many other biological molecules and the processes of prenylation in different macromolecules have been widely studied. We present here a new chemical biology technique to identify and label i6A, a prenyl-modified RNA residue, based on the unique reactivity of the prenyl group. We also found that iodine-mediated cycloaddition reactions of the prenyl group occurs in a superfast manner, and converts i6A from a hydrogen-bond acceptor into a donor. Based on this reactivity, we developed an iodine-mediated oxidation and reverse transcription (IMORT) method to profile cellular i6A residues with a single-base resolution, allowing for the transcriptome-wide detection and analysis of various i6A-containing RNA species.

biochemistry↗

The role of proton in a eukaryotic zinc transporter

Zinc transporter 8 (ZnT8) is mainly expressed in pancreatic islet {beta} cells and is responsible for H+-coupled uptake (antiport) of Zn2+ into the lumen of insulin secretory granules. Structures of human ZnT8 and its prokaryotic homolog YiiP have provided structural basis for constructing a plausible transport cycle for Zn2+. However, the mechanistic role that protons play in the transport process remains unclear. Here we present a lumen-facing cryo-EM structure of ZnT8 from Xenopus tropicalis (xtZnT8) in the presence of Zn2+ at a luminal pH (5.5). Compared to a Zn2+-bound xtZnT8 structure at a cytosolic pH (7.5), the low-pH structure displays an empty transmembrane Zn2+-binding site with a disrupted coordination geometry. Combined with a Zn2+-binding assay our data suggest that protons may disrupt Zn2+ coordination at the transmembrane Zn2+-binding site in the lumen-facing state, thus facilitating Zn2+ release from ZnT8 into the lumen.

biochemistry↗

Enhancer-promoter contact formation requires RNAPII and antagonizes loop extrusion

Mammalian chromosomes are folded by converging and opposing forces. Here, we tested the role of RNAPII across different scales of interphase chromatin folding in a cellular system allowing for its auxin-mediated degradation. We used Micro-C and computational modeling to characterize subsets of loops differentially gained or lost upon RNAPII depletion. Gained loops, extrusion of which was antagonized by RNAPII, almost invariably formed by engaging new or rewired CTCF anchors. Lost loops selectively concerned contacts between enhancers and promoters anchored by RNAPII. Surprisingly, promoter-promoter contacts were almost insensitive to polymerase depletion and sustained cohesin occupancy in its absence. Selective loss of enhancer-promoter contacts explains the repression of most genes. Together, our findings reconcile the role of RNAPII in transcription with that in setting-up regulatory 3D chromatin architectures genome-wide, while also revealing a direct impact on cohesin loop extrusion.

genomics↗

SiPLATZ12 transcript factor regulates multiple yield traits and salt tolerance in foxtail millet (Setaria italica)

Grain yield and salt tolerance are critical for crop production. However, the genetic and biochemical basis underlying the trade-off of these characters remain poorly described in crops. We show here that SiPLATZ12 transcription factor positively regulates multiple elite yield traits at the expense of salt tolerance in foxtail millet. SiPLATZ12 overexpression increases seed size, panicle length, and stem diameter, while reduces plant height and salt tolerance of foxtail millet. A 9-bp insertion in the SiPLATZ12 promoter has significant effects on the different expression of SiPLATZ12, multiple yield traits, and salt tolerance between foxtail millet and its wild ancestor, green foxtail. Moreover, SiPLATZ12 upregulates the expression of genes involved in seed development, but repressing the transcription of most NHX, SOS, and CBL genes to regulate Na+, K+ and pH homeostasis. Therefore, our results uncover a domesticated site that could be used to improve grain yield and salt tolerance in foxtail millet.

molecular biology↗

Integrated analysis of intestinal microbiota and metabolomic reveals that decapod iridescent virus 1 (DIV1) infection induces secondary bacterial infection and metabolic reprogramming in Marsupenaeus japonicus

In recent years, with global warming and increasing marine pollution, some novel marine viruses have become widespread in the aquaculture industry, causing huge losses to the aquaculture industry. Decapod iridescent virus 1 (DIV1) is one of the newly discovered marine viruses that has been reported to be detected in a variety of farmed crustacean and wild populations. Previous studies have found that DIV1 can induce the Warburg effect. To further explore the effect of DIV1-induced metabolic reprogramming on Marsupenaeus japonicus intestinal metabolome and microbiota and the consequence on immune response, histological analysis, enzyme activity analysis and the integrated analysis of intestinal microbiome and metabolomics were performed in this study. The results showed that obvious injury in the intestinal mucosa was observed after DIV1 infection. The oxidative and antioxidant capacity of the shrimp intestine was unbalanced, the activity of lysozyme was decreased, and the activities of digestive enzymes were disordered, causing secondary bacterial infection. In addition, the increased abundance of harmful bacteria, such as Photobacterium and Vibrio, synergized with DIV1 to promote the Warburg effect and induce metabolic reprogramming, thereby providing material and energy for DIV1 replication. This study is the first to report the changes of intestinal microbiota and metabolites of M. japonicus under DIV1 infection, demonstrating that DIV1 can induce secondary bacterial infection and metabolic reprogramming, and several highly related bacteria and metabolites were screened as biomarkers. These biomarkers can be leveraged for diagnosis of pathogenic infections or incorporated as exogenous metabolites to enhance immune response.

microbiology↗

Systems Analysis of de novo Mutations in Congenital Heart Diseases Identified a Molecular Network in Hypoplastic Left Heart Syndrome

Congenital heart diseases (CHD) are a class of birth defects affecting [~]1% of live births. These conditions are hallmarked by extreme genetic heterogeneity, and therefore, despite a strong genetic component, only a very handful of at-risk loci in CHD have been identified. We herein introduced systems analyses to uncover the hidden organization on biological networks of genomic mutations in CHD, and leveraged network analysis techniques to integrate the human interactome, large-scale patient exomes, the fetal heart spatial transcriptomes, and single-cell transcriptomes of clinical samples. We identified a highly connected network in CHD where most of the member proteins had previously uncharacterized functions in regulating fetal heart development. While genes on the network displayed strong enrichment for heart-specific functions, a sub-group, active specifically at early developmental stages, also regulates fetal brain development, thereby providing mechanistic insights into the clinical comorbidities between CHD and neurodevelopmental conditions. At a small scale, we experimentally verified previously uncharacterized cardiac functions of several novel proteins employing cellular assays and gene editing techniques. At a global scale, our study revealed developmental dynamics of the identified CHD network and observed the strongest enrichment for pathogenic mutations in the network specific to hypoplastic left heart syndrome (HLHS). Our single-cell transcriptome analysis further identified pervasive dysregulation of the network in cardiac endothelial cells and the conduction system in the HLHS left ventricle. Taken together, our systems analyses identified novel factors in CHD, revealed key molecular mechanisms in HLHS, and provides a generalizable framework readily applicable to studying many other complex diseases.

systems biology↗

New Hydra Genomes Reveal Conserved Principles of Hydrozoan Transcriptional Regulation

The epithelial and interstitial stem cells of the freshwater polyp Hydra are the best characterized stem cell systems in any cnidarian, providing valuable insight into cell type evolution and the origin of stemness in animals. However, little is known about the transcriptional regulatory mechanisms that determine how these stem cells are maintained and how they give rise to their diverse differentiated progeny. To address such questions, a thorough understanding of transcriptional regulation in Hydra is needed. To this end, we generated extensive new resources for characterizing transcriptional regulation in Hydra, including new genome assemblies for Hydra oligactis and the AEP strain of Hydra vulgaris, an updated whole-animal single-cell RNA-seq atlas, and genome-wide maps of chromatin interactions, chromatin accessibility, sequence conservation, and histone modifications. These data revealed the existence of large chromatin interaction domains in the Hydra genome that likely influence transcriptional regulation in a manner distinct from topologically associating domains in bilaterians. We also uncovered the transcriptomic profiles of two previously molecularly uncharacterized cell types, isorhiza-containing nematocytes and somatic gonad ectoderm. We identified novel candidate regulators of cell-type-specific transcription, several of which have likely been conserved at least since the divergence of Hydra and the jellyfish Clytia hemisphaerica over 200 million years ago. The resources generated in this study, which collectively represent the most comprehensive characterization of transcriptional regulation in a cnidarian to date, are accessible through a newly created genome portal, available at research.nhgri.nih.gov/HydraAEP/.

developmental biology↗

Differences in neurotoxic outcomes of organophosphorus pesticides revealed via multi-dimensional screening in adult and regenerating planarians

Organophosphorus pesticides (OPs) are a chemically diverse class of commonly used insecticides. Epidemiological studies suggest that low dose chronic prenatal and infant exposures can lead to life-long neurological damage and behavioral disorders. While inhibition of acetylcholinesterase (AChE) is the shared mechanism of acute OP neurotoxicity, OP-induced developmental neurotoxicity (DNT) can occur independently and/or in the absence of significant AChE inhibition, implying that OPs affect alternative targets. Moreover, different OPs can cause different adverse outcomes, suggesting that different OPs act through different mechanisms. These findings emphasize the importance of comparative studies of OP toxicity. Freshwater planarians are an invertebrate system that uniquely allows for automated, rapid and inexpensive testing of adult and developing organisms in parallel to differentiate neurotoxicity from DNT. Effects found only in regenerating planarians would be indicative of DNT, whereas shared effects may represent neurotoxicity. We leverage this unique feature of planarians to investigate potential differential effects of OPs on the adult and developing brain by performing a comparative screen to test 7 OPs (acephate, chlorpyrifos, dichlorvos, diazinon, malathion, parathion and profenofos) across 10 concentrations in quarter-log steps. Neurotoxicity was evaluated using a wide range of quantitative morphological and behavioral readouts. AChE activity was measured using an Ellman assay. The toxicological profiles of the 7 OPs differed across the OPs and between adult and regenerating planarians. Toxicological profiles were not correlated with levels of AChE inhibition. Twenty-two "mechanistic control compounds" known to target pathways suggested in the literature to be affected by OPs (cholinergic neurotransmission, serotonin neurotransmission, endocannabinoid system, cytoskeleton, adenyl cyclase and oxidative stress) and 2 negative controls were also screened. When compared with the mechanistic control compounds, the phenotypic profiles of the different OPs separated into distinct clusters. The phenotypic profiles of adult vs regenerating planarians exposed to the OPs clustered differently, suggesting some developmental-specific mechanisms. These results further support findings in other systems that OPs cause different adverse outcomes in the (developing) brain and build the foundation for future comparative studies focused on delineating the mechanisms of OP neurotoxicity in planarians.

pharmacology and toxicology↗

A pangenome analysis pipeline (PSVCP) provides insights into rice functional gene identification

BackgroundA pangenome aims to capture the complete genetic diversity within a species and reduce bias in genetic analysis inherent in using a single reference genome. However, the current linear format of most plant pangenomes limits the presentation of position information for novel sequences. Graph pangenomes have been developed to overcome this limitation. However, there is a lack of bioinformatics analysis tools for graph format genomes. ResultsTo overcome this problem, we have developed a novel pangenome construction strategy and a downstream pangenome analysis pipeline that captures position information while maintaining a linearized layout. We applied this strategy to construct a high-quality rice pangenome using 12 representative rice genomes and analyze an international rice panel with 413 diverse accessions using the pangenome reference. Our results provide insights into rice population structure and genomic diversity. Applying the pangenome for PAV-based GWAS analysis can identify causal structural variations for rice grain weight and plant height, while SNP-based GWAS can only identify approximate genomic locations. Additionally, a new locus (qPH8-1) was found to be associated with plant height on chromosome 8 that could not be detected using the SNP-based GWAS. ConclusionsOur results demonstrate that the pangenome constructed by our pipeline combined with PAV-based GWAS can provide additional power for genomic and genetic analysis. The pangenome constructed in this study and associated genome sequence data provide valuable genomic resources for future rice crop improvement.

genetics↗