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. 2026 Apr 3;16:15918. doi: 10.1038/s41598-026-46606-7

Genome-wide identification and expression analysis of the expansin gene family in Brassica napus L

Wen Luo 1,2,#, Ji Zhang 3,#, Heng Zhang 1,2, Kun Bao 1,2, Wei Yan 1,2, Xinrong Qin 1,2,✉
PMCID: PMC13195113  PMID: 41933006

Abstract

Expansins (EXPs) are a class of proteins that cause the relaxation of plant cell walls, thereby playing a role in regulating cell growth and various developmental processes in plants. In this study, a comprehensive analysis of the EXP gene family in Brassica napus L. (B. napus) was conducted, 127 EXP genes of B. napus identified using the ZS11 reference genome. These genes were classified into four subfamilies: alpha-expansin (EXPA), beta-expansin (EXPB), expansin-like A (EXLA), and expansin-like B (EXLB), with 98, 18, 5, and 6 members, respectively, evenly distributed across 19 chromosomes. The physicochemical properties, motif structures, and chromosomal distribution of these genes were evaluated. Evolutionary analysis within and between genomes indicated that the EXP genes(BnaEXs) exhibit a high degree of conservation., and segmental duplication was identified as the primary driver of the expansion of the BnaEXs in B. napus. Additionally, synteny analysis between B. napus, Arabidopsis thaliana L. and Nicotiana tabacum L. revealed that BnaEXs exhibit diverse evolutionary patterns across different plant species. The gene expression levels of the B. napus transcriptome database (BnPIR) demonstrated that most members are expressed in at least one tissue of B. napus. The differential expression of eight BnaEXs in response to various stress conditions and across different tissues was demonstrated by qPCR. The results of this study provide a solid foundation for further elucidating the biological functions of expansin genes in B. napus development and offer valuable genetic resources for future crop improvement.

Supplementary Information

The online version contains supplementary material available at 10.1038/s41598-026-46606-7.

Keywords: Expansins, Gene family, Brassica napus L., Gene expression profiles

Subject terms: Biotechnology, Computational biology and bioinformatics, Genetics, Molecular biology, Plant sciences

Introduction

Brassica napus L., commonly known as rapeseed, is the world’s second-largest oilseed crop and holds significant economic value. It is an important oilseed crop in China, serving as a key source of edible vegetable oil and feed protein. This species is a typical allopolyploid, resulting from the natural interspecific hybridisation between Brassica rapa (AA, n = 10) and Brassica oleracea (CC, n = 9). The yield of B. napus is influenced by various biotic and abiotic stresses. The loosening of the cell wall is the first step in plant cell growth, a process regulated by the EXP gene family1.

The increase in both cell number and volume relies on the loosening of the cell wall, which is crucial for plant growth and development2. Expansins are a type of cell wall-loosening proteins widely found in higher plants, bacteria, and fungi. These proteins enable cell expansion driven by turgor pressure3. EXP proteins typically consist of 250–275 amino acid residues and are composed of three domains: an N-terminal signal peptide and two conserved domains, Domain I and Domain II. The signal peptide, generally comprising 20–30 amino acid residues, targets the proteins to the cell wall. Domain I (DPBB_1) contains 120–135 amino acid residues and is rich in cysteine, which is characteristic of its catalytic domain4. Domain II is homologous to group-2 grass pollen allergens。Due to the unique modification effects of expansins on cell walls, they have garnered attention in studies related to fibre development in cotton and ramie. Research has shown that three genes encoding expansins are upregulated in the upper stem bark of ramie5,6.

The expansin family is an ancient and conserved large gene family, currently classified into four subfamilies: EXPA, EXPB, EXLA, and EXLB. The EXPA subfamily, first identified in cucumber, is primarily involved in plant growth and development7,8. In recent years, with the deepening of genome sequencing and advancements in genome assembly technologies, expansin genes have been identified and analysed in an increasing number of species, such as Arabidopsis thaliana, Populus, Ginkgo biloba, and rice9.

Expansins play crucial roles in processes such as seed germination, salt tolerance, drought resistance, fruit ripening, and root elongation10–12. They are indispensable components of plant genomes. In Arabidopsis, AtEXPA4 and AtEXPB5 are essential for pollen tube growth13. AtEXPA4 also promotes root growth and development by enhancing the elongation of the primary root and root meristem. In soybean, overexpression of GmEXPB2 leads to significant changes in root size by increasing cell division and elongation14. In rice, overexpression of OsEXPA8 results in increased plant height and leaf size, attributed to enhanced cell wall remodelling during cell expansion15.

Thus, expansins play a crucial role in crop development, yet research on expansins in rapeseed remains limited. Brassicaceae expansin studies have focused on Arabidopsis (26 members) and B. rapa (35 members), they lack data on allotetraploid B. napus. The genome of B. napus has been continuously sequenced and resequenced, and these genomic data make it possible to perform a comprehensive genome-wide identification of gene families16. This study primarily focuses on the expansin gene family in rapeseed. The findings provide a foundation for further research into the biological functions of expansin genes during rapeseed development and other developmental processes.

Materials and methods

Gene identify

Members of the AtEXPs gene family were selected from the TAIR(The Arabidopsis Information Resource) database (https://www.arabidopsis.org/)17. Protein sequences, genome files, and gene annotation files for B. napus cultivar Zhongshuang 11 (ZS11) were downloaded from the BnPIR database (http://cbi.hzau.edu.cn/bnapus/)16. Using AtEXPs protein sequences as query sequences, alignment and screening were performed with TBtools software18. Hidden Markov Models (HMM) for AtEXPs proteins were obtained from the Pfam database (https://pfam.xfam.org/search/) (PF01357 and PF03330, E-value < 0.01)19. HMM searches were conducted with AtEXPs HMM models as seed sequences (https://www.ebi.ac.uk/)20. Protein sequences obtained from the two methods were compared and deduplicated. Protein annotation, secondary structure, and conserved domains were verified using NCBI Blast Protein(nih.gov)21, UniProt (https://www.uniprot.org/), and CD-search (https://www.ncbi.nlm.nih.gov/Structure/cdd/wrpsb.cgi)22. The identified BnaEXs protein members were renamed accordingly. Physicochemical properties and chromosomal localization predictions were performed using ProtParam from Expasy (https://www.expasy.org/) and TBtools software23.

Phylogenetic analysis and gene duplication analysis

Protein sequences and genome files for Arabidopsis thaliana and Nicotiana tabacum were downloaded from the EnsemblPlants database (https://plants.ensembl.org/)24. Members of the Arabidopsis AtEXPs gene family were obtained from https://www.arabidopsis.org/, and members of the tobacco NtEXPs gene family were sourced from reported literature25. In total, 87 protein sequences (comprising 35 from Arabidopsis and 52 from Tobacco) were used in the analysis. Multiple sequence alignment was performed on these protein sequences using the MUSCLE algorithm implemented in MEGA with default parameters. We performed multiple sequence alignment using MEGA1128 software and checked the alignment results. Due to the high alignment quality of all sequences, we did not perform additional cropping on the results. Phylogenetic trees were then constructed using the Neighbor-Joining method in MEGA with 1000 bootstrap replicates. Although the sequences exhibited variation in length, all sequences were retained to capture the full diversity of the gene family; The evolutionary trees were visualized and modified using iTOL (https://itol.embl.de/)24. We used the default parameters of the Multiple Collinearity Scan toolkit (MCScanX) to detect gene duplication, and the resulting alignments were incorporated into the KaKs Calculator to determine the Ka/Ks (non-synonymous/synonymous substitution) values. Among the 254 segmental pairs, 196 pairs that met length and alignment quality criteria were used for Ka/Ks calculation.

Analysis of gene structure, motifs, conserved domains, and cis-acting elements

Upstream sequences were extracted using TBtools. Specifically, based on the genome annotation files, the upstream regions of the target genes were defined by setting a predetermined length (e.g., 2000 bp upstream of the transcription start site). TBtools was then employed to batch-extract these sequences from the genomic data. PlantCare (https://bioinformatics.psb.ugent.be/webtools/plantcare/html/)27for cis-acting element prediction. Gene structure, conserved motifs, conserved domains in the CDS regionswere analyzed using the following tools: GSDS (http://gsds.gao-lab.org/)25 for gene structure, MEME (https://meme-suite.org/meme/doc/meme.html)26for motif discovery, CD-search for conserved domains, Signal peptide prediction using SignalP (https://services.healthtech.dtu.dk/services/SignalP-4.1/). Using MEME (https://meme-suite.org/meme/ ) Analyze the conserved motifs in BnaEXs protein, with a maximum motif count of 12.

Expression pattern analysis

Transcript levels of BnaEXs in different tissues and at various developmental stages of B. napus were retrieved from the BnTIR transcriptome database (http://yanglab.hzau.edu.cn/BnTIR/). Obtain the transcription levels of BnaEXs in the root, stem, leaf, bud flower, silique, silique wall, seed, leaves and seeds of B. napus at 20 and 40 days after flowering, and use TBtools software to draw heat maps of gene expression levels. Gene expression heatmaps were generated using TBtools software28.

Stress treatment and qRT-PCR

Seeds were germinated in a seedling substrate, and uniformly growing seedlings were transplanted into soil (The seeds of Zhongshuang 11 (ZS11) were provided by Guizhou Rapeseed Research Institute.). The plants were then placed in a temperature-controlled light incubator with conditions of (25 ± 1)℃, light intensity of 13,000 Lux, and a light cycle of 16 h light/8 h darkness. When the plants developed three true leaves, they were subjected to cold (4℃), high temperature (38℃), and drought (20% PEG6000) treatments for 24 h. Subsequently, roots, stems, and leaves were quickly frozen in liquid nitrogen and stored at − 80℃. The RNAprep Pure Plant Kit (TIANGEN, DP432) was used to extract total RNA from samples. The cDNA was generated using the FastKing gDNA Dispelling RT Super-Mix kit (TIANGEN, KR118), following manufacturer’s instructions. A total of 8 highly expressed BnaEXs-related genes from the transcriptome were selected, and primers were designed using Primer 5.0 software (Table S9). Primer specificity was confirmed by conventional PCR and agarose gel electrophoresis. qRT-PCR was carried out with SYBR qPCR Mix Ultra (Lamarck) on a BIO-RAD CFX96 system. qRT-PCR was performed with Actin as the internal control gene, and relative gene expression was analyzed using the 2−ΔΔCT method29.

Statistical analysis methods

Statistical analysis was conducted using SPSS to perform variance analysis of the data. Data comparisons were made using the Least Significant Difference (LSD) test at the 0.05 and 0.01 significance levels. GraphPad Prism 9.0 was used for generating graphs.

Results

Identification and phylogenetic analysis of the expansin gene family in B. napus

We identified the expansin gene family in the B. napus ZS11 genome. By comparing with Arabidopsis expansins via BLAST (Table S1, Supplement file 1) and analyzing Pfam domains (PF01357 and PF03330), a total of 127 expansin genes were ultimately identified. To facilitate further analysis, each expansin gene was named according to their chromosomal coordinates (Table S2).

To evaluate the evolutionary relationships of expansins in B. napus, a phylogenetic tree was constructed in conjunction with expansins from Arabidopsis and tobacco (Fig. 1, Supplement file 2). The results revealed that the expansin gene family in rapeseed is similar to those in Arabidopsis and tobacco, comprising four subfamilies: EXPA, EXPB, EXLA, and EXLB. The EXPA subfamily is the largest, with 98 members; the EXPB subfamily has 18 members; the EXLA subfamily contains 5 members; and the EXLB subfamily includes 6 members.

Fig. 1.

Fig. 1

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Phylogenetic analysis and subfamily classification of expansin genes (BnaEXs) in B. napus.

We also analyzed the biochemical characteristics of the expansin proteins (Table S3). The sequence length of expansins ranges from 123 amino acids (BnaEXPA59) to 839 amino acids (BnaEXPA74). The isoelectric point (pI) of expansin family members varies from 4.81 (BnaEXPB13) to 11.6 (BnaEXPA59), with an average of 8.68. The average molecular weight (MW) of expansin family members is 28.15 kD, with a range from 13.55 kD (BnaEXPA59) to 90.65 kD (BnaEXPA74).

Gene structure and motifs of BnaEXs

We analyzed the gene structure, domains, and conserved motifs of expansin family members (Fig. 1). The BnaEXs gene family features five distinct conserved motifs (Fig. 2A). Motifs 1–5 are predominantly present in members of the EXPA subfamily. Motifs 1 and 5 are highly conserved in most B. napus EXP proteins. Motif 1 is almost universally present in the other three subfamilies, showing similarity in the motifs. Motif 2 was not found in EXLA or EXPB. In addition, the type, arrangement, and number of motifs were similar within the same subfamily.

Fig. 2.

Fig. 2

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Phylogenetic relationships, conserved motifs, and gene structure of BnaEXs Genes. (A) phylogenetic tree constructed based on BnaEXs sequences. Five conserved motifs of expansin proteins are distinguished by different colors. (B) Gene structure of BnaEXs expansin proteins.

The distribution of the number, length, and patterns of exons and introns is crucial for understanding the structural evolution and functional differences among gene family members. Gene structure analysis revealed that EXP family genes have 2 to 22 exons, with the majority containing 2–3 exons (Fig. 2B). In most homologous EXP gene pairs across B. napus genomes, the protein motifs and gene structures are similar, indicating a high level of conservation. Due to the fact that the expansion protein belongs to the secretory cell wall protein, we conducted signal peptide prediction and found that a total of 103 BnaEXs genes have signal peptides (Supplementary file 3).

Chromosomal localization and intraspecific synteny analysis of BnaEXs

We identified the chromosomal locations of BnaEXs genes in rapeseed (Fig. 3). A total of 125 expansin genes are distributed across 19 chromosomes, with 2 genes not mapped to any chromosome. The number of expansin genes per chromosome ranges from 2 to 14. Additionally, some expansin genes are clustered on specific chromosomes; for example, chromosome C04 contains 14 different expansin genes.

Fig. 3.

Fig. 3

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Syntenic Localization of Expansin Genes in the B. napus Genome. From outer to inner: The first circle represents the chromosome coordinates. The second circle indicates the gene density distribution. The third circle indicates all synteny blocks.

To further understand the evolution of BnaEXs genes, we investigated genomic duplication events (Fig. 3). Synteny analysis revealed frequent collinearity of expansin genes between genomes (Fig. 3). This analysis identified 254 pairs of genes with segmental duplications (Table S4) and 1 pair of genes with gene duplications (Table S5). Moreover, the rates of Ka/Ks were calculated to estimate selection pressure on BnaEXs. Our result shows that the Ka/Ks values of segmental pairs genes the Ka/Ks values were recorded < 1. The results clarify the evolution of all gene pairs is affected by purification selection. These findings suggest that segmental duplication is a major driver of the evolutionary expansion of the BnaEXs gene family, and expansin genes with synteny may share similar functions.

Inter-species synteny and cis-acting element analysis of BnaEXs

An inter-species synteny analysis was performed between BnaEXs genes and those in Arabidopsis thaliana and Nicotiana tabacum (Fig. 4). The analysis revealed 178 pairs of segmental duplication genes between rapeseed and Arabidopsis, with 108 genes showing syntenic relationships in Arabidopsis. Between rapeseed and tobacco, 103 pairs of segmental duplication genes were identified, with 62 genes having syntenic relationships in tobacco (Table S6). These syntenic EXs genes are thought to be conserved during evolution and may regulate the same traits.

Fig. 4.

Fig. 4

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Inter-species homology analysis of BnaEXs, Tobacco, and Arabidopsis thaliana genes.

Cis-acting elements in the promoter regions of the BnaEXs family can be broadly categorized into three classes (Figure S1, Table S7). The first class consists of light-responsive elements; the second includes hormone-responsive elements, such as those responsive to auxin, gibberellin, salicylic acid, and methyl jasmonate; and the third class comprises stress-responsive elements, including MYB binding sites, drought, temperature, and anaerobic responsive elements. Among all stress-responsive cis-acting elements, anaerobic induction and methyl jasmonate response elements are the most abundant, 85.03% (108/127) contain ‘anaerobic’ elements, and 66.14% (84/127) contain ‘methyl jasmonate response’ elements, suggesting that BnaEXs are involved in various intracellular stress responses, especially waterlogging stress, and are regulated by a wide range of hormones.

BnaEXs expression pattern analysis

To understand the potential functions of BnaEXs gene family members, RNA-seq data for BnaEXs across different tissues (bud, filament, cotyledon, root, seed, silique, stem) under various stress conditions (salt, drought, freezing, cold, heat, and osmotic) were analyzed (Fig. 5). Most genes were expressed across different tissues and stress conditions (Table S8). Only a few of the 6 genes (BnaEXPA44, BnaEXPA87, Bnascalfold 0027T0000800ZS, Bnascalfold 0027T0000800ZS, BnaEXPB11, and BnaEXPB12) were not expressed in any part of the plant, indicating that the EXP family plays an important role in rapeseed. Notably, BnaEXPA81 showed the highest expression in buds, BnaEXPA4 in filaments, BnaEXPA8 in cotyledons, BnaEXPA73 in roots, BnaEXPA84 in seeds, BnaEXPA83 in siliques, and BnaEXPA34 in the lower stem peel.

Fig. 5.

Fig. 5

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Expression levels of BnaEXs family genes in different tissues and under various stress conditions. Normalized expression values are color-coded based on log2(FPKM + 1).

BnaEXPA8 exhibited the highest expression levels under normal and heat stress conditions, BnaEXLB1 was highly expressed under salt stress, and BnaEXPA81 showed high expression under drought and osmotic stress. BnaEXPA8 and BnaEXPA41 were prominently expressed under freezing and cold stress conditions.

Among these genes, BnaEXPA8, BnaEXPA34, BnaEXPA41, BnaEXPA81, BnaEXPA83, and BnaEXPA84 were consistently expressed in various tissues and under different stress conditions, indicating their stable expression within the BnaEXs family.

Each BnaEX subfamily had distinct tissue-specific expression in B. napus. EXPA was the dominant subfamily across all tissues, with high expression in vegetative organs (roots, cotyledons, stems) and reproductive organs (buds, siliques, seeds) via representative genes. EXPB showed low, restricted expression in few tissues with no tissue dominance. EXLA was specifically dominant in seeds, implying roles in seed development. EXLB only dominated in roots under stress (e.g., salt), with weak expression in other tissues and normal conditions.

qRT-PCR analysis of BnaEXs genes

Based on promoter element analysis and specific expression patterns of BnaEXs genes, we identified several abiotic stress-responsive elements potentially associated with their expression (Table S10). We selected 8 BnaEXs rich in low-temperature, high-temperature, and drought stress cis-elements (Table S9). The qRT-PCR results (Fig. 6) showed that BnaEXPA7 exhibited the highest expression in roots, with a significant increase under cold, heat, and drought stress, showing a 2.5-fold increase in roots and 1.8-fold increase in stems, but expression was less than 0.5-fold in leaves. BnaEXPA34 had the highest expression in stems (3.2-fold higher than control), followed by leaves, and its expression significantly decreased under all stress conditions (fold-change ≤ 0.6-fold). BnaEXPA41 was highly expressed in leaves, with cold stress inducing a 4.5-fold increase in expression, while heat and drought significantly down-regulated it (≤ 0.5-fold). BnaEXPA72 showed the highest expression in stems, with a declining trend under stress conditions (0.4-fold under heat), and no significant change in root expression under heat stress (stable at 1.0-fold). BnaEXPA73 had the highest expression in roots (3.0-fold higher under heat stress), and a notable decrease under cold stress, showing a 0.4-fold expression in roots and stems under that condition. BnaEXPA77 was most highly expressed in leaves, with cold stress significantly upregulating its expression (2.2-fold), while heat and drought stress notably decreased its expression in leaves (≤ 0.5-fold). BnaEXPA81 was predominantly expressed in leaves, showing a 2.3-fold increase in roots under drought stress, suggesting its crucial role in drought stress response. Finally, BnaEXPA84 was highly expressed in leaves, with a significant decrease in stem expression under heat stress (0.3-fold decrease) and a notable decrease in leaf expression under both cold and heat stress (0.6-fold decrease).

Fig. 6.

Fig. 6

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Expression patterns of 8 BnaEXs genes in different tissues and under various stress conditions in B. napus. The qRT-PCR experiments were conducted with three independent replicates, and the error bars in the figure represent the errors from these three independent experiments. Different lowercase letters in the figure indicate significant differences (P < 0.05).

To strengthen the link between cis-element predictions and experimental results, we analyzed the promoters of the 8 BnaEX genes using Table S7 data. Genes with stress-enhanced expression (BnaEXPA7, BnaEXPA73, BnaEXPA81) had abundant, diverse stress elements: BnaEXPA7 contained 6 ABA-responsive elements + 1 drought-MYB site; BnaEXPA73 had 4 low-temperature elements; BnaEXPA81 harbored 1 drought-MYB site, matching their stress-specific upregulation. Genes with stress-decreased expression (e.g., BnaEXPA77, BnaEXPA34) either had few total elements (BnaEXPA77: 4 total) or lacked key elements (BnaEXPA34: no MeJA elements), preventing effective stress-induced activation.These results suggest that BnaEXPA7 can enhance expression to combat abiotic stress, BnaEXPA73 can increase expression under heat stress, and BnaEXPA81 plays a significant role in drought stress regulation by increasing expression in roots. In contrast, stress conditions decrease the expression levels of BnaEXPA34, EXPA41, EXPA72, EXPA77, and EXPA84.

Discussion

Plant growth is driven by cell proliferation and expansion, which is constrained by the cell wall, thereby limiting the increase in protoplasm. The cell wall restricts the rapid expansion of protoplasm within plant cells, while expansin proteins loosen the cell wall by breaking hydrogen bonds between cellulose microfibrils and hemicelluloses. Expansin proteins play a crucial role in plant growth and development. This study employed bioinformatics tools to analyse the expansin gene family in B. napus to better understand their function.

The expansin gene family in B. napus comprises 127 members. Each gene in the family contains two conserved domains, DPBB_1 and Pollen_allerg_1, which is consistent with findings in Arabidopsis9 and tobacco30. Therefore, these are typical plant expansins. Phylogenetic analysis revealed that the 127 expansin proteins can be classified into four subfamilies. Within each subfamily, the expansin genes in B. napus show structural similarity, and their structure and evolutionary characteristics are consistent with expansin gene families in other plants31. This confirms their close evolutionary relationships and systematic classification.

During the long evolutionary process of angiosperms, widespread polyploidy events have led to gene duplication and the expansion of gene families32. Our results indicate that the majority of EXP homologous gene pairs are the result of segmental duplications, suggesting that segmental duplication is the primary driving force behind the expansion of the EXP gene family in B. napus. We also observed a significant number of segmental duplications between B. napus, Arabidopsis, and tobacco. These collinear EXs genes show conservation in evolution and may regulate similar traits, with the functions of expansin proteins in Arabidopsis and tobacco serving as references for B. napus.

EXP genes have been demonstrated to be crucial regulatory factors in the development of various plant organs, such as roots, leaves, seeds, and fruits33,34. In this study, BnaEXs exhibited different expression patterns across various tissues and under different stress conditions. The BnaEX showed distinct tissue-specific dominant expression characteristics in B. napus, with EXPA as the core dominant subfamily in almost all vegetative and reproductive organs, while EXLA and EXLB exhibited specific dominant expression in seeds and stress-induced roots, respectively, which reflected the functional differentiation of different subfamilies during the evolution of the expansin gene family. For instance, BnaEXPA8, BnaEXPA34, BnaEXPA41, BnaEXPA81, BnaEXPA83, and BnaEXPA84 showed high expression across different tissues and stress conditions and were confirmed to have high expression levels in qRT-PCR analyses. Additionally, the variation in expression patterns among some homologous genes indicates functional divergence following gene duplication, which may be attributed to differences in the number of cis-elements in the promoter regions of homologous genes.

EXLA and EXLB are two smaller subfamilies of expansin proteins, and their biological functions are not yet well understood2. In our study, we identified 5 EXLA proteins and 6 EXLB proteins. We found that EXLA genes are highly expressed in seeds, suggesting that they may play a crucial role in the early stages of growth, potentially preparing seeds for germination. Catiempo et al.35demonstrated through transcriptome analysis that the expansion protein gene EXLA plays an important role in improving sunflower seed germination. It has been reported that Arabidopsis AtEXLA2 is prominently expressed in the hypocotyl and root; overexpression of AtEXLA2 leads to slightly thicker cell walls in non-rapidly elongating hypocotyl cells36. Our research showed that EXLB is highly expressed in roots under salt and osmotic stress, with weaker expression under other conditions. This suggests that EXLB is likely involved in osmotic stress responses through the root system, and this warrants further investigation.

In summary, the BnaEXs family in B. napus plays a crucial role in response to abiotic stress.. The comprehensive genome-wide identification and characterization of expansin genes in B. napus provide a critical foundation for further research into the functions of these genes.

Supplementary Information

Supplementary Information 1. (57.6KB, txt)
Supplementary Information 2. (6.9KB, nwk)
Supplementary Information 3. (5KB, txt)
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Supplementary Information 14. (115.5KB, xls)

Author contributions

WL and XQ planned and designed the research, analyzed the data, and wrote the manuscript. JZ and KB performed most of the field work; WL, and HZ carried out the molecular biology and chemistry studies. XQ conceived the study and participated in the design and coordination. All authors reviewed the manuscript.

Funding

The study is supported by Qiannongke General Fund [2025]36.

Data availability

All data generated or analysed during this study are included in this published article and its supplementary information files.

Declarations

Competing interests

The authors declare no competing interests.

Ethics

Not applicable. The samples were collected from private land, and all samples were collected with protocols approved by the owner. Since this study did not involve any endangered or protected species, no ethical approval or consent was required.

Footnotes

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Wen Luo, Ji Zhang are the authors contributed equally to this paper and should be considered as co-first author.

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