Guangnan Xing

Soybean ( Glycine max [L.] Merr.) was domesticated in China over five millennia ago; yet, its global expansion has resulted in two distinct, independently evolved breeding pools in China and the Americas. While regional breeding has optimized specific traits, a comprehensive roadmap for the reciprocal exchange of these “breeding‐specific” beneficial alleles is lacking. Here, we performed a large‐scale genomic dissection of 2,377 soybean accessions, integrating 8.4 million high‐quality SNPs with multi‐environment phenotyping across 11 locations. Through genome‐wide association studies (GWAS), we identified 261 significant loci (223 novel) governing six key agronomic traits, revealing that Chinese and American germplasms have accumulated distinct sets of beneficial alleles of seed size/protein in China and oil/yield in the Americas. To harness this untapped potential, we developed the Soybean Targeted Improvement Navigation System (STINS), a framework integrating population genomics, GWAS, and genomic selection (GS). We demonstrate the potential of targeted beneficial allele introgression between populations via gene modification for rapid trait improvement. Proof‐of‐concept functional evaluation through CRISPR/Cas9‐mediated knockout of GmST05 in an American cultivar and overexpression of a resistant GmSNAP18 haplotype in a Chinese cultivar provided experimental support for STINS‐predicted targets for protein content and SCN resistance improvement. Our study provides a navigable genomic resource for “knowledge‐driven design breeding”, offering a blueprint for the global exchange of elite alleles to ensure future food security.

The subgenus Soja , including annual wild ( Glycine soja ) and cultivated soybean ( Glycine max ), is the primary germplasm source of soybeans. We analyzed the genome constitution of 750 wild and cultivated accessions from the Chinese Soybean Germplasm Population (CSGP), covering ~20.42% genic and ~79.58% intergenic regions. Most previous genomic studies focused on gene compositions and functions, with intergenic regions being non‐emphasized yet. Our results showed: (i) We defined 48,465 gene blocks (2–23 alleles/gene block) in the genic region. For intergenic region partitioning, the linkage‐disequilibrium (LD) confidence interval (CI) method performed the best, identifying 137,104 SNP LD blocks (SNPLDBs, 2–24 haplotypes/SNPLDB). (ii) Wild and cultivated accessions shared 98.5%/80.9% genes/alleles and 88.0%/80.8% SNPLDBs/haplotypes, indicating high wild genomic contribution to the cultivated genome; genic and intergenic regions exhibit distinct allele/haplotype dynamics during domestication. (iii) We proposed the three‐case restricted two‐stage multi‐locus multi‐allele genome‐wide association study (three‐case RTM‐GWAS), identifying 82 day‐to‐flowering (DTF) main‐effect genes and 47 intergenic‐SNPLDB‐impacted genes (by 34 SNPLDBs) (total 129 genes, 746 alleles). These explained 98.87% of phenotypic variance (PV), with main‐effect and SNPLDB‐impacted genes accounting for 68.61% and 30.26% PV, respectively; gene‐allele(s) impacted by SNPLDB‐haplotype (one/both sides) were also identified. (iv) Domestication process excluded more large‐effect positive alleles that shorten DTF in cultivated accessions, enhancing DTF's transgressive recombination potential in earliness. This study provides insights into genic/intergenic genome regions, offering a novel understanding of soybean functional genomics.

Annual wild soybean, the ancestor of cultivated soybean, underwent a significant increase in seed oil content during domestication. To elucidate the genetic basis of this change, a chromosome segment substitution line population (177 lines) constructed with cultivated soybean NN1138-2 as recipient and wild soybean N24852 as donor was used in this study. Phenotypic evaluation across three distinct environments led to the identification of two major QTL/segments, qOC14 on chromosome 14 and qOC20 on chromosome 20, which collectively explained 39.46% of the phenotypic variation, with individual contributions of 17.87% and 21.59%, respectively. Both wild alleles exhibited negative additive effects, with values of −0.35% and −0.42%, respectively, consistent with the inherently low oil content of wild soybeans. Leveraging transcriptome and genome data from the two parents, two candidate genes were predicted. Notably, Glyma.14G179800 is a novel candidate gene encoding a PHD-type zinc finger domain-containing protein, and the hap-A haplotype exhibits a positive effect on oil content. In contrast, Glyma.20G085100 is a reported POWR1 gene, known to regulate protein and oil content. Our findings not only validate the role of known gene but, more importantly, unveil a new candidate gene, offering valuable genetic resources and theoretical targets for molecular breeding of high-oil soybean.

Annual wild soybean is characterized by a high protein content. To elucidate the genetic basis, this study utilized a chromosome segment substitution line population (177 lines) constructed with cultivated soybean NN1138-2 as the recipient and wild soybean N24852 as the donor. Phenotypic analyses across three environments revealed significant variation in protein content ranging from 42.86% to 49.08%, with a high heritability of 0.70, indicating strong genetic control. Through high-throughput sequencing, six wild segments associated with high protein content were detected on chromosomes 3, 6, 9, 15, and 20, with phenotypic variation explained (PVE) by individual segments ranged from 3.58% to 22.46%, with segments on chromosomes 9, 15, and 20 as large-effect segments with PVE > 10%. All wild segments exhibited positive additive effects (0.42–1.09%), consistent with the characteristic of a high protein content in wild soybean. Compared with previous studies, five segments overlapped with reported loci, while qPro6.1 on chromosome 6 was a novel discovery. Integration of genomic and transcriptomic data identified 10 genes involved in nucleic acid binding, transmembrane protein transport, and amino acid synthesis pathway, with homologs validated in soybean, rice, and rapeseed. This research deepens the understanding of wild soybean’s high protein and offers new gene resources for breeding high-protein cultivated soybean.

Phytophthora soja e-induced root rot poses a major threat to soybean production. While the molecular mechanisms underlying soybean– P. sojae interactions have been extensively studied, their biochemical basis remains largely unexplored. Previous research has identified key metabolic modules involved in pathogen defense, but structural diversity has largely been constrained by studies on single soybean accessions. Here, we broadened the chemical search space to a diverse soybean germplasm collection using high-throughput metabolomics as a powerful tool for comprehensive metabolic profiling. Chemical classes of lipids and phenylpropanoids again retrieved the most pronounced responses upon P. sojae infection in general. A two-layer analytical strategy further finely resolved metabolites into pathogenesis-, resistance-, and tolerance-type accumulation patterns, leading to the identification of cinnamaldehyde and coumestrol as potent defense metabolites. Bioassays validated cinnamaldehyde directly and strongly inhibited cyst germination and mycelial growth, and coumestrol, a benzofuran-type metabolite, exhibited broad-spectrum activity against spore germination as an identified phytoalexin. Multiomics analyses nailed down the candidate of coumestrol biosynthesis genes, and genetically overexpression of regulatory genes ( Dir2a/4a/4b ) in hairy root systems increased coumestrol accumulation thus positively correlating with improved host resistance. Interestingly, tolerance-type compounds may serve distinct ecological roles, as exemplified by daidzein, which, despite being classified as a tolerance-type metabolite, recruits more zoospores facilitating secondary infection in fact. This study highlights a systematic approach for population-level investigations and emphasizes the necessity of integrating bioinformatics with experimental validation to accurately predict metabolite or gene ecological functions.

Key message A wild-allele GsPP2C-51-a1 of Glyma.14g162100 was identified in SojaCSSLP5, back to wild soybean, conferring drought tolerance. Its functions were verified in transgenic hairy root soybeans and Arabidopsis under water deficit and ABA treatment. Abstract A population of wild soybean chromosome segment substitution lines (CSSLs), SojaCSSLP5, with NN1138-2 as the cultivated recurrent parent and N24852 as the wild donor parent, was used to identify drought-tolerant loci/segments from the donor. Relative shoot dry weight, a tolerance indicator, varied significantly among the parents and CSSLs. Six drought tolerance loci/segments were detected in SojaCSSLP5, including Gm14_LDB_21 with GsPP2C-51 (Glyma.14g162100) as one of the four possible genes. This gene belongs to the F1 clade of protein phosphatase 2C based on gene ontology annotation, qPCR, and previous research results. Glyma.14g162100 was traced back to the Chinese germplasm population, in which four alleles existed on the locus, with soja holding all four, and max holding only two without any new alleles emerging. N24852 and NN1138-2 hold a1 and a2, respectively. The GsPP2C-51 protein was located inside the nucleus. In transgenic hairy root composite soybean, the GsPP2C-51-a1 overexpressed plants maintained a higher leaf fresh weight (tolerance) under 15% PEG stress compared to the empty vector plants. This was strongly supported by improved tolerance, chlorophyll content, and a series of physiological responses in GsPP2C-51-a1 overexpressed Arabidopsis plants under water deficit and abscisic acid treatments. Thus, the wild-type allele GsPP2C-51-a1 (Glyma.14g162100a1) from N24852 positively regulates plant drought tolerance.

Clanis bilineata tsingtauica Mell (CBT) is a traditional edible insect. This study aimed to (1) establish an in-situ procedure for determining the suitability of soybean varieties for CBT rearing and (2) identify soybean varieties that are most conducive to CBT rearing. We developed two isolation rearing methods: the first employs mesh bags as isolation rearing tools in net houses (BIRN) and fields (BIRF), and the second uses net houses directly as isolation rearing tools (IRN). The suitability of fourteen soybean varieties with different maturity groups to CBT was assessed. Based on F values and genetic variation coefficients from single-factor and combined variance analyses across various environments, the weight of 15-day-old larvae was identified as the primary suitability indicator for BIRN and BIRF, and the 25-day-old larvae weight per plot was selected as the key indicator for IRN. BIRN and BIRF methods offer advantages such as moderate cost and high throughput, completing evaluations in just one-sixths of the consumable expenses required by IFN. IRN method more accurately reflects actual production condition, with larvae reared on mid-late maturing, lodging-resistant soybean varieties achieving significantly higher larval weights than those reared on other types of soybean varieties. BIRN and BIRF methods evaluate soybean varieties suitability for CBT primarily based on larval weight, whereas IRN considers both larval weight and larval survival rate. Thus, IRN provides a comprehensive assessment of soybean varieties suitability for CBT. BIRN and BIRF allow for multiple evaluations annually with low consumable expenses, while IRN can be employed to select varieties based on initial screening results from BIRN and BIRF. The combination of mesh bag and net house isolation rearing methods facilitates the identification of specialized soybean varieties for CBT rearing. By integrating both methods, two soybean varieties, NN18-25 and NN1138-2, were specifically identified optimal for CBT larval rearing.

Shade tolerance is a key trait for cultivars in inter/relay-cropped soybeans in maize fields. Our previous genome-wide association study (GWAS) results on southern China soybean germplasm revealed that the shade tolerance was conferred by a complex of genes with multiple alleles. To complete our understanding of the shade tolerance gene system, GWAS with gene–allele sequences as markers (designated GASM-RTM-GWAS) was conducted in a recombinant inbred line (RIL) population between two extreme parents using the shade tolerance index (STI) and relative pith cell length (RCL) as indicators. Altogether, 211 genes, comprising 99 and 119 genes (seven shared) for STI and RCL, respectively, were identified and then annotated into a similar set of five biological categories. Furthermore, transcriptome analysis detected 7837 differentially expressed genes (DEGs), indicating plentiful DEGs involved in the expression of regulatory/causal GWAS genes. Protein–protein interaction (PPI) analysis and gene functional analysis for both GWAS genes and DEGs showed a group of interrelated causal genes and a group of interrelated DEGs; the former were included in the latter and their functions were interconnected as a gene network. For further understanding of the response of soybean to shade stress in a sequential connection, six chronological gene modules were grouped as signal activation and transport, signal-transduction, signal amplification, gene expression, regulated metabolites, and material transport. From the modules, 12 key genes were selected as entry points for further analysis. Our study provides an overview of the shade tolerance gene network as a new insight into a complex-trait genetic system, rather than the usual way of starting from a hand-picked single gene.

The soybean hawkmoth Clanis bilineata tsingtauica Mell (Lepidoptera, Sphingidae; CBT), as one of the main leaf-chewing pests of soybeans, has gained popularity as an edible insect in China recently due to its high nutritional value. However, high-quality genome of CBT remains unclear, which greatly limits further research. In the present study, we assembled a high-quality chromosome-level genome of CBT using PacBio HiFi reads and Hi-C technologies for the first time. The size of the assembled genome is 477.45 Mb with a contig N50 length of 17.43 Mb. After Hi-C scaffolding, the contigs were anchored to 29 chromosomes with a mapping rate of 99.61%. Benchmarking Universal Single-Copy Orthologues (BUSCO) completeness value is 99.49%. The genome contains 252.16 Mb of repeat elements and 14,214 protein-coding genes. In addition, chromosomal synteny analysis showed that the genome of CBT has a strong synteny with that of Manduca sexta. In conclusion, this high-quality genome provides an important resource for future studies of CBT and contributes to the development of integrated pest management strategies.