Systematic identification of wheat spike developmental regulators by integrated multiomics, transcriptional network, GWAS, and genetic analyses

The spike architecture of wheat plays a crucial role in determining grain number,making it a key trait for optimization in wheat breeding programs.In this study,we used a multi-omic approach to analyze the transcriptome and epigenome profiles of the young spike at eight developmental stages,revealing co-ordinated changes in chromatin accessibility and H3K27me3 abundance during the flowering transition.We constructed a core transcriptional regulatory network(TRN)that drives wheat spike formation and experimentally validated a multi-layer regulatorymodule involving TaSPL15,TaAGLG1,and TaFUL2.By integrating the TRN with genome-wide association studies,we identified 227 transcription factors,including 42 with known functions and 185 with unknown functions.Further investigation of 61 novel transcription factors using multiple homozygous mutant lines revealed 36 transcription factors that regulate spike architecture or flowering time,such as TaMYC2-A1,TaMYB30-A1,and TaWRKY37-A1.Of particular interest,TaMYB30-A1,downstream of and repressed by WFzP,was found to regulate fertile spikelet number.Notably,the excellent haplotype of TaMYB30-A1,which contains a C allele at the WFzP binding site,was enriched during wheat breeding improvement in China,leading to improved agronomic traits.Finally,we constructed a free and open access Wheat Spike Multi-Omic Database(http://39.98.48.156:8800/#/).Our study identifies novel and high-confidence regulators and offers an effective strategy for dissecting the genetic basis of wheat spike development,with practical value forwheat breeding.

Boosting wheat functional genomics via an indexed EMS mutant library of KN9204

A better understanding of wheat functional genomics can improve targeted breeding for better agronomic traits and environmental adaptation.However,the lack of gene-indexed mutants and the low transformation efficiency of wheat limit in-depth gene functional studies and genetic manipulation for breeding.In this study,we created a library for KN9204,a popular wheat variety in northern China,with a reference genome,transcriptome,and epigenome of different tissues,using ethyl methyl sulfonate(EMS)mutagenesis.This library contains a vast developmental diversity of critical tissues and transition stages.Exome capture sequencing of 2090 mutant lines using KN9204 genome-designed probes revealed that 98.79%of coding genes had mutations,and each line had an average of 1383 EMS-type SNPs.We identified new allelic variations for crucial agronomic trait-related genes such as Rht-D1,Q,TaTB1,and WFZP.We tested 100 lines with severemutations in 80 NAC transcription factors(TFs)under drought and salinity stress and identified 13 lines with altered sensitivity.Further analysis of three lines using transcriptome and chromatin accessibility data revealed hundreds of direct NAC targets with altered transcription patterns under salt or drought stress,including SNAC1,DREB2B,CML16,and ZFP182,factors known to respond to abiotic stress.Thus,we have generated and indexed a KN9204 EMS mutant library that can facilitate functional genomics research and offer resources for genetic manipulation of wheat.

Genome sequencing of Sitopsis species provides insights into their contribution to the B subgenome of bread wheat

Wheat(Triticum aestivum,BBAADD)is an allohexaploid species that originated from two polyploidization events.The progenitors of the A and D subgenomes have been identified as Triticum urartu and Aegilops tauschii,respectively.Current research suggests that Aegilops speltoides is the closest but not the direct ancestor of the B subgenome.However,whether Ae.speltoides has contributed genomically to the wheat B subgenome and which chromosome regions are conserved between Ae.speltoides and the B subgenome remain unclear.Here,we assembled a high-quality reference genome for Ae.speltoides,resequenced 53 accessions from seven species(Aegilops bicornis,Aegilops longissima,Aegilops searsii,Aegilops sharonensis,Ae.speltoides,Aegilops mutica[syn.Amblyopyrum muticum],and Triticumdicoccoides)and revealed their genomic contributions to the wheat B subgenome.Our results showed that centromeric regions were particularly conserved between Aegilops and Triticum and revealed 0.17 Gb of conserved blocks between Ae.speltoides and the B subgenome.We classified five groups of conserved and non-conserved genes between Aegilops and Triticum,revealing their biological characteristics,differentiation in gene expression patterns,and collinear relationships between Ae.speltoides and the wheat B subgenome.We also identified gene families that expanded in Ae.speltoides during its evolution and 789 genes specific to Ae.speltoides.These genes can serve as genetic resources for improvement of adaptability to biotic and abiotic stress.The newly constructed reference genome and large-scale resequencing data for Sitopsis species will provide a valuable genomic resource for wheat genetic improvement and genomic studies.

WheatGmap:a comprehensive platform for wheat gene mapping and genomic studies

Bulked segregant analysis(BSA)is an efficient and low-cost strategy that is widely used to identify causal genes in segregating populations.BSA-based methods,such as BSA sequencing(Wenger et al.,2010),bulked segregant RNA sequencing(BSR-seq)(del Viso et al.,2012),and MutMap(Abe et al.,2012),are powerful tools that can be used for rapidly discovering genetic markers and gene mapping.Although BSA is increasingly being used in wheat(Triticum aestivum)gene mapping efforts,few user-friendly BSA tools have been developed for researchers lacking a strong bioinformatics background.Here,we developed the web-based BSA platform WheatGmap(https://www.wheatgmap.org),which integrates multiple BSA mapping models and large amounts of public data to accelerate gene cloning and functional research and facilitate resource sharing.

A bipolar modified separator using TiO2 nanosheets anchored on N-doped carbon scaffold for high-performance Li–S batteries

Lithium-sulfur batteries hold promise for next generation batteries due to their high theoretical energy density and low cost.However,the rapid capacity fading caused by the shuttle of polysulfide between two electrodes severely hinders the practical application of Li-S batteries.To address the issue,we reported a three-dimensional heterostructured TiO2 nanosheets/N-doped carbon(TO/NC),which is coated on a commercial polypro pylene(PP) separator,as an efficient barrier for Li-S batteries.The TO/NC coating layer provides a bipolar chemical adsorption of lithium polysulfides(LiPSs) via TiO2 nanosheets with exposed(001) facets and N-doped carbon,showing high trapping capacity and remarkable electrocatalytic activity for LiPSs.The slurry-bladed carbon black/sulfur cathode with 64 wt% sulfur offers outstanding performance with an initial capacity of 1314 mAh g^-1 at 0.2 C.Over 900 cycles,the cell still maintains the capacity of 448 mA h g^-1 at a 1 C rate with a degradation rate of only 0.055% per cycle.The separator reported in this work holds great promise for the development of high-energy Li-S batteries.