Triptolide is a trace natural product of Tripterygium wilfordii. It has antitumor activities, particularly against pancreatic cancer cells. Identification of genes and elucidation of the biosynthetic ...pathway leading to triptolide are the prerequisite for heterologous bioproduction. Here, we report a reference-grade genome of T. wilfordii with a contig N50 of 4.36 Mb. We show that copy numbers of triptolide biosynthetic pathway genes are impacted by a recent whole-genome triplication event. We further integrate genomic, transcriptomic, and metabolomic data to map a gene-to-metabolite network. This leads to the identification of a cytochrome P450 (CYP728B70) that can catalyze oxidation of a methyl to the acid moiety of dehydroabietic acid in triptolide biosynthesis. We think the genomic resource and the candidate genes reported here set the foundation to fully reveal triptolide biosynthetic pathway and consequently the heterologous bioproduction.
Chrysanthemum (Chrysanthemum morifolium Ramat.) is a globally important ornamental plant with great economic, cultural, and symbolic value. However, research on chrysanthemum is challenging due to ...its complex genetic background. Here, we report a near-complete assembly and annotation for C. morifolium comprising 27 pseudochromosomes (8.15 Gb; scaffold N50 of 303.69 Mb). Comparative and evolutionary analyses reveal a whole-genome triplication (WGT) event shared by Chrysanthemum species approximately 6 million years ago (Mya) and the possible lineage-specific polyploidization of C. morifolium approximately 3 Mya. Multilevel evidence suggests that C. morifolium is likely a segmental allopolyploid. Furthermore, a combination of genomics and transcriptomics approaches demonstrate the C. morifolium genome can be used to identify genes underlying key ornamental traits. Phylogenetic analysis of CmCCD4a traces the flower colour breeding history of cultivated chrysanthemum. Genomic resources generated from this study could help to accelerate chrysanthemum genetic improvement.
Pre-harvest sprouting (PHS), the germination of seeds on the plant prior to harvest, poses significant challenges to agriculture. It not only reduces seed and grain yield, but also impairs the ...commodity quality of the fruit, ultimately affecting the success of the subsequent crop cycle. A deeper understanding of PHS is essential for guiding future breeding strategies, mitigating its impact on seed production rates and the commercial quality of fruits. PHS is a complex phenomenon influenced by genetic, physiological, and environmental factors. Many of these factors exert their influence on PHS through the intricate regulation of plant hormones responsible for seed germination. While numerous genes related to PHS have been identified in food crops, the study of PHS in vegetable crops is still in its early stages. This review delves into the regulatory elements, functional genes, and recent research developments related to PHS in vegetable crops. Meanwhile, this paper presents a novel understanding of PHS, aiming to serve as a reference for the study of this trait in vegetable crops.
Maize (
L.) is a tropical crop, and low temperature has become one of the main abiotic stresses for maize growth and development, affecting many maize growth processes. The main area of maize ...production in China, Jilin province, often suffers from varying degrees of cold damage in spring, which seriously affects the quality and yield of maize. In the face of global climate change and food security concerns, discovering cold tolerance genes, developing cold tolerance molecular markers, and creating cold-tolerant germplasm have become urgent for improving maize resilience against these conditions and obtaining an increase in overall yield. In this study, whole-genome sequencing and genotyping by sequencing were used to perform genome-wide association analysis (GWAS) and quantitative trait locus (QTL) mapping of the two populations, respectively. Overall, four single-nucleotide polymorphisms (SNPs) and 12 QTLs were found to be significantly associated with cold tolerance. Through joint analysis, an intersection of GWAS and QTL mapping was found on chromosome 3, on which the
gene was identified as a potential factor in cold tolerance. We verified the function of this target gene through overexpression, suppression of expression, and genetic transformation into maize. We found that
overexpression resulted in better cold tolerance in this crop. The identification of genes associated with cold tolerance contributes to the clarification of the underlying mechanism of this trait in maize and provides a foundation for the adaptation of maize to colder environments in the future, to ensure food security.
Sweetpotato (Ipomoea batatas (L.) Lam.) is the seventh most important crop in the world and is mainly cultivated for its underground storage root (SR). The genetic studies of this species have been ...hindered by a lack of high-quality reference sequence due to its complex genome structure. Diploid Ipomoea trifida is the closest relative and putative progenitor of sweetpotato, which is considered a model species for sweetpotato, including genetic, cytological, and physiological analyses.
Here, we generated the chromosome-scale genome sequence of SR-forming diploid I. trifida var. Y22 with high heterozygosity (2.20%). Although the chromosome-based synteny analysis revealed that the I. trifida shared conserved karyotype with Ipomoea nil after the separation, I. trifida had a much smaller genome than I. nil due to more efficient eliminations of LTR-retrotransposons and lack of species-specific amplification bursts of LTR-RTs. A comparison with four non-SR-forming species showed that the evolution of the beta-amylase gene family may be related to SR formation. We further investigated the relationship of the key gene BMY11 (with identity 47.12% to beta-amylase 1) with this important agronomic trait by both gene expression profiling and quantitative trait locus (QTL) mapping. And combining SR morphology and structure, gene expression profiling and qPCR results, we deduced that the products of the activity of BMY11 in splitting starch granules and be recycled to synthesize larger granules, contributing to starch accumulation and SR swelling. Moreover, we found the expression pattern of BMY11, sporamin proteins and the key genes involved in carbohydrate metabolism and stele lignification were similar to that of sweetpotato during the SR development.
We constructed the high-quality genome reference of the highly heterozygous I. trifida through a combined approach and this genome enables a better resolution of the genomics feature and genome evolutions of this species. Sweetpotato SR development genes can be identified in I. trifida and these genes perform similar functions and patterns, showed that the diploid I. trifida var. Y22 with typical SR could be considered an ideal model for the studies of sweetpotato SR development.
The hollow cylinders of TiB-Ti composites with a gradient distribution of Ti phase were synthesized by the combination of traditional slurry spray with centrifugal forming process. The influences of ...the concentration of sodium hexametaphosphate (SHMP), the concentration of polyvinyl alcohol (PVA) and solid content (20 vol%–35 vol%) on the rheological properties of the TiB
2
−Ti composite slurries were investigated. Slurries with low viscosity, weak thixotropy and shear-thinning behaviour were obtained for facilitating the slurry spraying process. The effects of different centrifugal conditions on the migration of components during the forming process were studied. The phase composition and the elements distribution of the prepared samples were characterized by the energy-dispersive X-ray spectrometer. The observations revealed that the samples fabricated at 1 500 r/min for 3 min had a significant composition variation. For two-phase systems with small density differences and large particle size variation, centrifugal time was more important than centrifugal speed in forming a continuous gradient structure.
The spatial–temporal simulation of fire disasters and evacuation route planning are important research fields for urban emergency responses and are primary tasks that answer complex questions after ...fires break out. The increasing demand for refined building information models will sharply increase the calculated and analyzed quantity. This demand presents a challenge for fire emergency responses based on massive building information. In this paper, the principle of the realistic worst case (RWC) is introduced into fire simulation and evacuation route planning. Taking the library of the Nanjing Forestry University as the study object, the spatial–temporal characteristics of the influential environmental factors of the fire are simulated, such as the meteorological elements, building structure, and building skin. The scenario zones that are relatively prone to fire are selected using an overlay analysis across the four seasons. Then, the risk threshold for evacuating personnel is analyzed in the fire zone according to international standards and firefighting criteria. Specific parameters are determined based on the analysis of the above. The growing trends for fires across the four seasons are simulated with scenario zones as the starting positions and incorporate factors such as temperature, carbon monoxide, and smoke. Lastly, a life safety assurance path (LSAP) for personnel evacuation is designed based on an indoor road network and path search algorithm. The evacuation planning result is compared with the traditional shortest-time path and shortest-distance path. Based on the study results, fire scenario zones can improve the speed and operating efficiency of spatial–temporal simulation models of fire and can also support path planning and design for emergency responses.
The theoretical basis of the preparation of phase change energy storage materials is analyzed firstly, and then the preparation methods of fatty acid phase change energy storage materials are ...analyzed in detail. Furthermore, the application of phase change energy storage materials in building energy saving is analyzed. Finally, combined with the above contents, the application prospect and research direction of phase change energy storage materials are briefly described.
Artificially improving persimmon (Diospyros kaki Thunb.), one of the most important fruit trees, remains challenging owing to the lack of reference genomes. In this study, we generated an ...allele-aware chromosome-level genome assembly for the autohexaploid persimmon 'Xiaoguotianshi' (Chinese-PCNA type) using PacBio CCS and Hi-C technology. The final assembly contained 4.52 Gb, with a contig N50 value of 5.28 Mb and scaffold N50 value of 44.01 Mb, of which 4.06 Gb (89.87%) of the assembly were anchored onto 90 chromosome-level pseudomolecules comprising 15 homologous groups with 6 allelic chromosomes in each. A total of 153,288 protein-coding genes were predicted, of which 98.60% were functionally annotated. Repetitive sequences accounted for 64.02% of the genome; and 110,480 rRNAs, 12,297 tRNAs, 1,483 miRNAs, and 3,510 snRNA genes were also identified. This genome assembly fills the knowledge gap in the autohexaploid persimmon genome, which is conducive in the study on the regulatory mechanisms underlying the major economically advantageous traits of persimmons and promoting breeding programs.
Abstract
Jujube (
Ziziphus jujuba
Mill.) is an important perennial fruit tree with a range of interesting horticultural traits. It was domesticated from wild jujube (
Ziziphus acidojujuba
), but the ...genomic variation dynamics and genetic changes underlying its horticultural traits during domestication are poorly understood. Here, we report a comprehensive genome variation map based on the resequencing of 350 accessions, including wild, semi-wild and cultivated jujube plants, at a >15× depth. Using the combination of a genome-wide association study (GWAS) and selective sweep analysis, we identified several candidate genes potentially involved in regulating seven domestication traits in jujube. For fruit shape and kernel shape, we integrated the GWAS approach with transcriptome profiling data, expression analysis and the transgenic validation of a candidate gene to identify a causal gene,
ZjFS3
, which encodes an ethylene-responsive transcription factor. Similarly, we identified a candidate gene for bearing-shoot length and the number of leaves per bearing shoot and two candidate genes for the seed-setting rate using GWAS. In the selective sweep analysis, we also discovered several putative genes for the presence of prickles on bearing shoots and the postharvest shelf life of fleshy fruits. This study outlines the genetic basis of jujube domestication and evolution and provides a rich genomic resource for mining other horticulturally important genes in jujube.
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