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The controllable photocatalytic C−C coupling of methanol to produce ethylene glycol (EG) is a highly desirable but challenging objective for replacing the current energy‐intensive thermocatalytic process. Here, we develop a metal‐free porous boron nitride catalyst that demonstrates exceptional selectivity in the photocatalytic production of EG from methanol under mild conditions. Comprehensive experiments and calculations are conducted to thoroughly investigate the reaction mechanism, revealing that the OB3 unit in the porous BN plays a critical role in the preferential activation of C−H bond in methanol to form ⋅CH2OH via a concerted proton‐electron transfer mechanism. More prominent energy barriers are observed for the further dehydrogenation of the ⋅CH2OH intermediate on the OB3 unit, inhibiting the formation of some other by‐products during the catalytic process. Additionally, a small downhill energy barrier for the coupling of ⋅CH2OH in the OB3 unit promotes the selective generation of EG. This study provides valuable insights into the underlying mechanisms and can serve as a guide for the design and optimization of photocatalysts for efficient and selective EG production under mild conditions. [ABSTRACT FROM AUTHOR]

Polyploidy is recurrent across the tree of life and known as an evolutionary driving force in plant diversification and crop domestication. How polyploid plants adapt to various habitats has been a fundamental question that remained largely unanswered. Brassica napus is a major crop cultivated worldwide, resulting from allopolyploidy between unknown accessions of diploid B. rapa and B. oleracea. Here, we used whole-genome resequencing data of accessions representing the majority of morphotypes and ecotypes from the species B. rapa , B. oleracea , and B. napus to investigate the role of polyploidy during domestication. To do so, we first reconstructed the phylogenetic history of B. napus , which supported the hypothesis that the emergence of B. napus derived from the hybridization of European turnip of B. rapa and wild B. oleracea. These analyses also showed that morphotypes of swede and Siberian kale (used as vegetable and fodder) were domesticated before rapeseed (oil crop). We next observed that frequent interploidy introgressions from sympatric diploids were prominent throughout the domestication history of B. napus. Introgressed genomic regions were shown to increase the overall genetic diversity and tend to be localized in regions of high recombination. We detected numerous candidate adaptive introgressed regions and found evidence that some of the genes in these regions contributed to phenotypic diversification and adaptation of different morphotypes. Overall, our results shed light on the origin and domestication of B. napus and demonstrate interploidy introgression as an important mechanism that fuels rapid diversification in polyploid species. [ABSTRACT FROM AUTHOR]

Solar‐driven CO2 reduction reaction (CO2RR) with water into carbon‐neutral fuels is of great significance but remains challenging due to thermodynamic stability and kinetic inertness of CO2. Biomass‐derived nitrogen‐doped carbon (N‐Cb) have been considered as promising earth‐abundant photocatalysts for CO2RR, although their activities are not ideal and the reaction mechanism is still unclear. Herein, an efficient catalyst is developed for CO2‐to‐CO conversion realized on diverse N‐Cb materials with hierarchical pore structures. It is demonstrated that the CO2‐to‐CO conversion preferentially takes place on positively charged carbon atoms next to pyridinic‐N using two representatives treated pollens with the largest difference in pyridinic‐N density and N content as model photocatalysts. Systematic experimental results indicate that surface local electric field originating from charge separation can be boosted by hierarchical pore structures, doped N, as well as pyridinic‐N. Mechanistic studies reveal that positively charged carbon atoms next to pyridinic‐N serve as active sites for CO2RR, reduce the energy barrier on the formation of CO*, and facilitate the CO2RR performance. All these benefits cooperatively contribute to treated chrysanthemum pollen catalyst exhibiting excellent CO formation rate of 203.2 µmol h−1 g−1 with 97.2% selectivity in pure water vapor. These results provide a new perspective into CO2RR on N‐Cb, which shall guide the design of nature‐based photocatalysts for high‐performance solar‐fuel generation. [ABSTRACT FROM AUTHOR]

Physical contact between genes distant on chromosomes is a potentially important way for genes to coordinate their expressions. To investigate the potential importance of distant contacts, we performed high‐throughput chromatin conformation capture (Hi‐C) experiments on leaf nuclei isolated from Brassica rapa and Brassica oleracea. We then combined our results with published Hi‐C data from Arabidopsis thaliana. We found that distant genes come into physical contact and do so preferentially between the proximal promoter of one gene and the downstream region of another gene. Genes with higher numbers of conserved noncoding sequences (CNSs) nearby were more likely to have contact with distant genes. With more CNSs came higher numbers of transcription factor binding sites and more histone modifications associated with the activity. In addition, for the genes we studied, distant contacting genes with CNSs were more likely to be transcriptionally coordinated. These observations suggest that CNSs may enrich active histone modifications and recruit transcription factors, correlating with distant contacts to ensure coordinated expression. This study advances our knowledge of gene contacts and provides insights into the relationship between CNSs and distant gene contacts in plants. [ABSTRACT FROM AUTHOR]

Summary: Brassica rapa comprises many important cultivated vegetables and oil crops. However, Chiifu v3.0, the current B. rapa reference genome, still contains hundreds of gaps. Here, we presented a near‐complete genome assembly of B. rapa Chiifu v4.0, which was 424.59 Mb with only two gaps, using Oxford Nanopore Technology (ONT) ultralong‐read sequencing and Hi‐C technologies. The new assembly contains 12 contigs, with a contig N50 of 38.26 Mb. Eight of the ten chromosomes were entirely reconstructed in a single contig from telomere to telomere. We found that the centromeres were mainly invaded by ALE and CRM long terminal repeats (LTRs). Moreover, there is a high divergence of centromere length and sequence among B. rapa genomes. We further found that centromeres are enriched for Copia invaded at 0.14 MYA on average, while pericentromeres are enriched for Gypsy LTRs invaded at 0.51 MYA on average. These results indicated the different invasion mechanisms of LTRs between the two structures. In addition, a novel repetitive sequence PCR630 was identified in the pericentromeres of B. rapa. Overall, the near‐complete genome assembly, B. rapa Chiifu v4.0, offers valuable tools for genomic and genetic studies of Brassica species and provides new insights into the evolution of centromeres. [ABSTRACT FROM AUTHOR]

The species Brassica rapa includes enormous leafy vegetables with extreme leaf morphological diversity. Leaf traits such as size, shape, weight, and ratio of the leaf blade to the petiole contribute to yield, appearance, and desirability to consumers. These leaf-related traits are controlled by quantitative trait loci (QTLs). The construction of high-density bin maps using low-coverage sequencing is a powerful method for QTL fine-mapping and gene identification. In this study, we performed whole-genome re-sequencing of Wutacai 'Zhongbaye' and Chinese cabbage 'HN53' and 150 F2 individuals to construct a high-density bin map for QTL mapping of 11 leaf-related traits. The parental lines and F2 population were re-sequenced at 10x and 1x coverage, respectively. A map containing 565 bin markers was constructed based on parental single-nucleotide polymorphisms and a modified sliding window approach. The total map length was 944.6 cM and the average distance of the bins was 1.65 cM. In total, 60 significant QTLs controlling 11 leaf-related traits were detected. We further identified candidate genes responsible for these complex leaf-related traits. These findings suggest that this cost-effective bin-mapping approach is capable of rapid identification of QTLs and candidate genes, and will thus facilitate the dissection of the underlying molecular basis of leaf morphological variations and accelerate the improvement of B. rapa vegetable breeding. [ABSTRACT FROM AUTHOR]

Summary: Transposable element (TE) is prevalent in plant genomes. However, studies on their impact on phenotypic evolution in crop plants are relatively rare, because systematically identifying TE insertions within a species has been a challenge. Here, we present a novel approach for uncovering TE insertion polymorphisms (TIPs) using pan‐genome analysis combined with population‐scale resequencing, and we adopt this pipeline to retrieve TIPs in a Brassica rapa germplasm collection. We found that 23% of genes within the reference Chiifu‐401‐42 genome harbored TIPs. TIPs tended to have large transcriptional effects, including modifying gene expression levels and altering gene structure by introducing new introns. Among 524 diverse accessions, TIPs broadly influenced genes related to traits and acted a crucial role in the domestication of B. rapa morphotypes. As examples, four specific TIP‐containing genes were found to be candidates that potentially involved in various climatic conditions, promoting the formation of diverse vegetable crops in B. rapa. Our work reveals the hitherto hidden TIPs implicated in agronomic traits and highlights their widespread utility in studies of crop domestication. [ABSTRACT FROM AUTHOR]

SUMMARY: Leaf heading is an important and economically valuable horticultural trait in many vegetables. The formation of a leafy head is a specialized leaf morphogenesis characterized by the emergence of the enlarged incurving leaves. However, the transcriptional regulation mechanisms underlying the transition to leaf heading remain unclear. We carried out large‐scale time‐series transcriptome assays covering the major vegetative growth phases of two headingBrassica crops, Chinese cabbage and cabbage, with the non‐heading morphotype Taicai as the control. A regulatory transition stage that initiated the heading process is identified, accompanied by a developmental switch from rosette leaf to heading leaf in Chinese cabbages. This transition did not exist in the non‐heading control. Moreover, we reveal that the heading transition stage is also conserved in the cabbage clade. Chinese cabbage acquired through domestication a leafy head independently from the origins of heading in other cabbages; phylogenetics supports that the ancestor of all cabbages is non‐heading. The launch of the transition stage is closely associated with the ambient temperature. In addition, examination of the biological activities in the transition stage identified the ethylene pathway as particularly active, and we hypothesize that this pathway was targeted for selection for domestication to form the heading trait specifically in Chinese cabbage. In conclusion, our findings on the transcriptome transition that initiated the leaf heading in Chinese cabbage and cabbage provide a new perspective for future studies of leafy head crops. Significance Statement: By profiling the gene expression dynamics during the heading formation in Chinese cabbage and cabbage, as compared with a non‐heading control, we identified a conserved, temperature‐responsive Leaf Heading Transition Stage marked by the transcriptional reprogramming along with the development of folding leaves. We highlight the ethylene pathway, whose genes are activated during the transition in Chinese cabbage, as the unintended target of domestication, which implies the existence of significant variation within the ancestral non‐heading races. [ABSTRACT FROM AUTHOR]

The species Brassica rapa includes several important vegetable crops. The draft reference genome of B. rapa ssp. pekinensis was completed in 2011, and it has since been updated twice. The pangenome with structural variations of 18 B. rapa accessions was published in 2021. Although extensive genomic analysis has been conducted on B. rapa , a comprehensive genome annotation including gene structure, alternative splicing (AS) events, and non-coding genes is still lacking. Therefore, we used the Pacific Biosciences (PacBio) single-molecular long-read technology to improve gene models and produced the annotated genome version 3.5. In total, we obtained 753,041 full-length non-chimeric (FLNC) reads and collapsed these into 92,810 non-redundant consensus isoforms, capturing 48% of the genes annotated in the B. rapa reference genome annotation v3.1. Based on the isoform data, we identified 830 novel protein-coding genes that were missed in previous genome annotations, defined the untranslated regions (UTRs) of 20,340 annotated genes and corrected 886 wrongly spliced genes. We also identified 28,564 AS events and 1,480 long non-coding RNAs (lncRNAs). We produced a relatively complete and high-quality reference transcriptome for B. rapa that can facilitate further functional genomic research. [ABSTRACT FROM AUTHOR]

After removing low-quality cells and genes, we obtained 16 055 high-quality cells and 30 214 genes. Single-cell transcriptome reveals differentiation between adaxial and abaxial mesophyll cells in Brassica rapa Keywords: scRNA-seq; mesophyll cell; adaxial-abaxial polarity; ribosomal protein-encoding genes; Brassica rapa EN scRNA-seq mesophyll cell adaxial-abaxial polarity ribosomal protein-encoding genes Brassica rapa 2233 2235 3 11/22/22 20221201 NES 221201 Mesophyll cells are the main site of photosynthesis and the largest cell population in leaves, with tightly packed cylinder palisade mesophyll cells (PMCs) on the adaxial side and loosely arranged rounded spongy mesophyll cells (SMCs) on the abaxial side. Red dots indicate the reported genes involved in PMCs development in Arabidopsis, while green dots represent the top 10 genes with the most connections. [Extracted from the article]

Chinese cabbage is an important leaf heading vegetable crop. At the heading stage, its leaves across inner to outer show significant morphological differentiation. However, the genetic control of this complex leaf morphological differentiation remains unclear. Here, we reported the transcriptome profiling of Chinese cabbage plant at the heading stage using 24 spatially dissected tissues representing different regions of the inner to outer leaves. Genome-wide transcriptome analysis clearly separated the inner leaf tissues from the outer leaf tissues. In particular, we identified the key transition leaf by the spatial expression analysis of key genes for leaf development and sugar metabolism. We observed that the key transition leaves were the first inwardly curved ones. Surprisingly, most of the heading candidate genes identified by domestication selection analysis obviously showed a corresponding expression transition, supporting that key transition leaves are related to leafy head formation. The key transition leaves were controlled by a complex signal network, including not only internal hormones and protein kinases but also external light and other stimuli. Our findings provide new insights and the rich resource to unravel the genetic control of heading traits. [ABSTRACT FROM AUTHOR]

The LiF-rich solid electrolyte interphase (SEI) is an emerging research hotspot to improve battery performance. Its high Li-ion conductivity and high interfacial energy result in fast lithiation/de-lithiation in electrode materials while at the same time protect materials from pulverization. Currently, the developed LiF-rich SEI fabrication methods are based on electrolyte decomposition upon cycling, but so far have only been applied to Li metal or Si anodes. Furthermore, the influences of LiF on the electrochemical behavior of the electrolyte are not fully understood. Here, a new pre-coating approach is proposed to fabricate a conformal LiF layer on both anode and cathode materials (silicon suboxide (SiOx) and LiNi0.8Co0.1Mn0.1O2 (NCM811) as examples). LiF assisted the increase in the specific capacity of a SiOx electrode from 301 to 1034 mA h g−1 after 100 cycles at 500 mA g−1. In addition, a full cell assembled with a prepared anode (SiOG@LiF3) and cathode (NCM811@LiF3) showed outstanding cycling stability. Combining density functional theory (DFT) calculation with SEM and XPS characterization revealed for the first time that the pre-coating LiF layer had a strong preferential adsorption of LiPF6 molecules on the surface, leading to the formation of inorganic-rich SEI during cycling; thereby enabling a fast Li-ion uptake/removal process and improving the electrode integrity. [ABSTRACT FROM AUTHOR]