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🌿 TRACK 11 • 13 MODULAR CHAPTERS • HPC READY PacBio HiFi • Hi-C • EDTA • BRAKER3 • Minigraph-Cactus • GEMMA GWAS • Agricultural Genomics & Crop Breeding Pipelines

Plant, Polyploid & Non-Model Genomics

Master the computational bottlenecks of plant and agricultural genomics: extreme ploidy (allopolyploidy and autopolyploidy), massive repeat and transposable element (TE >80%) fractions, structural variation across pan-genomes, and genomic selection for quantitative crop breeding traits.

⚡ Quick-Start Conda Environment (Production CLI) Bioconda + Conda-Forge
# Create the Plant & Non-Model Genomics Production Environment
mamba create -n omics_plant -c bioconda -c conda-forge \
  kmc jellyfish genomescope2 hifiasm yahs juicer_tools \
  busco merqury quast edta repeatmasker braker3 eggnog-mapper \
  orthofinder mcscanx jcvi pggb vg syri vcftools pixy \
  admixture iqtree tassel gemma r-gapit r-qtlseqr r-rrblup -y

conda activate omics_plant
Interactive Pipeline Architecture (Click any stage to inspect CLI tools & hardware specs)
STAGE 01 • CH 01–04
Phased T2T Assembly
KMC3 • GenomeScope2 • Hifiasm • YaHS • LAI
STAGE 02 • CH 05–07
TEs & Gene Prediction
EDTA • RepeatMasker • BRAKER3 • EggNOG
STAGE 03 • CH 08–09
Synteny & Pan-Genomes
MCScanX • JCVI • WGDI • PGGB • SyRI
STAGE 04 • CH 10–13
GWAS, QTL-Seq & GS
Pixy • GAPIT3 • QTLseqr • rrBLUP
Stage 01: Polyploid Profiling & Haplotype-Resolved Assembly
Resolves heterozygosity and polyploid subgenomes using PacBio HiFi + Omni-C/Hi-C reads, scaffolded to chromosome scale and validated via BUSCO, Merqury QV, and LTR Assembly Index (LAI > 20).
⚡ 32–64 Cores • 128 GB RAM 📄 HiFi/Hi-C FASTQ → GFA → Chr.FASTA
Start Chapter 1 → All 11 Curricula → ⬇ Practice Datasets (104 MB) 13 Modular Chapters • Production Agricultural Toolchains
Chapter 01 PRE-ASSEMBLY QC • PLOIDY

01. K-mer Profiling, Genome Size & Ploidy Estimation

Before launching an expensive de novo assembly, estimate haploid genome size, repetitive fraction, heterozygosity rate, and ploidy level directly from unassembled HiFi or Illumina reads.

Tools: Jellyfish, KMC3, GenomeScope 2.0, Smudgeplot Output: Heterozygosity %, 1C size, Ploidy Smudgeplot Spec: 16 CPU Cores • 32 GB RAM
# 1. Count canonical 21-mers using KMC3
mkdir -p kmc_tmp
kmc -k21 -t16 -m32 -ci1 -cs10000 @hifi_reads.fofn kmer_counts kmc_tmp/
kmc_tools transform kmer_counts histogram kmer_k21.hist -cx10000

# 2. Run GenomeScope 2.0 (set -p 2 for diploid, -p 4 for tetraploid, -p 6 for hexaploid)
genomescope2 -i kmer_k21.hist -o genomescope_out -k 21 -p 2

# 3. Extract heterozygous k-mer pairs for Smudgeplot ploidy inference
L=$(smudgeplot.py cutoff kmer_k21.hist L)
U=$(smudgeplot.py cutoff kmer_k21.hist U)
kmc_tools transform kmer_counts -ci"$L" -cx"$U" dump -s kmer_L_U.dump
smudgeplot.py hetkmers -o kmer_pairs < kmer_L_U.dump
smudgeplot.py plot kmer_pairs_coverages.tsv -o plant_ploidy
Chapter 02 DE NOVO ASSEMBLY • HI-C PHASING

02. Haplotype-Resolved De Novo Assembly (Hifiasm)

Assemble phased haplotypes (hap1 and hap2) by integrating PacBio HiFi reads with Omni-C/Hi-C chromatin conformation reads, preventing artificial collapse of heterozygous regions or homeologous subgenomes.

Tools: Hifiasm (Hi-C Phasing Mode), Verkko, Bandage Output: Haplotype-resolved GFA & FASTA (hap1 • hap2 • primary) Spec: 32–64 CPU Cores • 128 GB RAM
# Haplotype-resolved assembly using PacBio HiFi + paired-end Hi-C reads
hifiasm -o cultivar_asm -t 48 \
  --h1 hic_R1.fastq.gz \
  --h2 hic_R2.fastq.gz \
  pacbio_hifi.fastq.gz

# Convert GFA assembly graphs to FASTA for Primary, Hap1, and Hap2
for hap in p_ctg hap1.p_ctg hap2.p_ctg; do
  awk '/^S/{print ">"$2"\n"$3}' cultivar_asm.hic.${hap}.gfa > cultivar_${hap}.fasta
done
Chapter 03 CHROMOSOME SCAFFOLDING

03. Chromosome-Scale Hi-C Scaffolding (YaHS + Juicer)

Order and orient contigs into chromosome-scale pseudomolecules using 3D chromatin contact frequencies.

Tools: YaHS, Juicer Tools, 3D-DNA, Juicebox Assembly Tools Output: Chromosome-scale pseudomolecules + .hic contact map Spec: 32 CPU Cores • 64 GB RAM
# 1. Align Hi-C reads with BWA-MEM2 (-5SP flags preserve 5' ligation junctions)
bwa-mem2 index cultivar_p_ctg.fasta
bwa-mem2 mem -5SP -t 32 cultivar_p_ctg.fasta hic_R1.fastq.gz hic_R2.fastq.gz | \
  samblaster | samtools view -Sb -h -F 2316 - > hic_aligned.bam

# 2. Sort by read name and scaffold with YaHS
samtools sort -n -@ 16 -o hic_namesorted.bam hic_aligned.bam
samtools faidx cultivar_p_ctg.fasta
yahs cultivar_p_ctg.fasta hic_namesorted.bam -o yahs_out
Chapter 04 BENCHMARKING • LAI

04. Assembly Quality, QV & LTR Assembly Index (LAI)

Evaluate gene space completeness (BUSCO), reference-free k-mer base accuracy (Merqury), and pericentromeric repeat continuity via the LTR Assembly Index (LAI)—where $\text{LAI} \ge 20$ defines a gold-standard plant reference.

Tools: BUSCO, Merqury, QUAST-LG, LTR_retriever Output: BUSCO %, Merqury QV > Q40, LAI Score > 20 (Gold Standard) Spec: 16 CPU Cores • 32 GB RAM
# 1. BUSCO Completeness against Embryophyta (Land Plants) OrthoDB v10
busco -i yahs_out_scaffolds_final.fa -l embryophyta_odb10 -o busco_plant -m genome -c 16

# 2. Merqury Reference-Free Consensus Quality (QV) & K-mer Completeness
meryl k=21 count output read_db.meryl pacbio_hifi.fastq.gz
merqury.sh read_db.meryl yahs_out_scaffolds_final.fa merqury_qc

# 3. Calculate LTR Assembly Index (LAI) via LTR_retriever
LTR_retriever -genome yahs_out_scaffolds_final.fa -inharvest raw_ltr.scn -threads 16
Chapter 05 REPEAT ANNOTATION • EDTA

05. Pan-TE & Repeat Annotation (EDTA)

Unmasked transposable elements corrupt gene predictors by introducing thousands of transposase open reading frames (ORFs). Build a curated, non-redundant pan-TE library covering LTRs (Gypsy/Copia), TIRs, and Helitrons.

Tools: EDTA, RepeatModeler2, RepeatMasker Output: Curated non-redundant TE library & Soft-masked FASTA Spec: 32 CPU Cores • 64 GB RAM
# Run Extensive de-novo TE Annotator (EDTA) and soft-mask the genome
EDTA.pl \
  --genome yahs_out_scaffolds_final.fa \
  --species others \
  --step all \
  --sensitive 1 \
  --anno 1 \
  --threads 32

# Generate soft-masked genome for BRAKER3 (--xsmall converts repeats to lowercase a/t/g/c)
RepeatMasker -pa 32 -s -xsmall \
  -lib yahs_out_scaffolds_final.fa.mod.EDTA.TElib.fa \
  yahs_out_scaffolds_final.fa
Chapter 06 EVIDENCE-GUIDED GENE PREDICTION

06. Evidence-Guided Gene Prediction (BRAKER3)

Combine multi-tissue bulk RNA-Seq alignments (HISAT2) with Viridiplantae OrthoDB protein homology hints to train GeneMark-ETP and AUGUSTUS inside the unified BRAKER3 pipeline.

Tools: BRAKER3, GeneMark-ETP, AUGUSTUS, TSEBRA Output: High-confidence gene models (GFF3/GTF) + Predicted Proteome FASTA Spec: 32 CPU Cores • 64 GB RAM
# Run BRAKER3 via Singularity/Apptainer container with RNA-Seq BAMs and Viridiplantae proteins
singularity exec -B $PWD:$PWD docker://teambraker/braker3:latest braker.pl \
  --genome=yahs_out_scaffolds_final.fa.masked \
  --bam=leaf_rnaseq.bam,root_rnaseq.bam,fruit_rnaseq.bam \
  --prot_seq=Viridiplantae_OrthoDB11.fa \
  --threads=32 \
  --gff3 \
  --species=solanum_cultivar_v1 \
  --workingdir=braker3_out
Chapter 07 FUNCTIONAL ANNOTATION • ORTHOLOGY

07. Non-Model Functional Annotation & MapMan Bins

Assign Gene Ontology (GO), KEGG orthologs (KO), Enzyme Commission (EC) numbers, Pfam domains, and plant-specific MapMan metabolic pathway bins to newly predicted proteome sequences.

Tools: EggNOG-mapper, InterProScan, Mercator4 / MapMan, OrthoFinder Output: Functional GFF3, KEGG pathway annotations, MapMan metabolic bins Spec: 24 CPU Cores • 48 GB RAM
# 1. Fast orthology-based functional annotation using EggNOG-mapper (DIAMOND mode)
emapper.py -i braker3_out/braker.aa \
  --itype proteins \
  -m diamond \
  --tax_scope 33090 \
  --cpu 24 \
  --output plant_proteome_func

# 2. Domain & family architecture scan via InterProScan
interproscan.sh -i braker3_out/braker.aa -f tsv,gff3 -dp -goterms -pa -cpu 24
Chapter 08 SYNTENY • WGD DATING (Ks)

08. Comparative Genomics, Collinearity & Paleopolyploidy ($K_s$)

Identify syntenic blocks across related species (MCScanX / JCVI) and compute synonymous substitution rates ($K_s$) between paralogous gene pairs to date Whole-Genome Duplication (WGD) events.

Tools: MCScanX, JCVI, WGDI, yn00 / KaKs_Calculator Output: Synteny ribbons, Dot plots, Ks distribution peaks dating WGD Spec: 16 CPU Cores • 32 GB RAM
# 1. All-vs-all DIAMOND BLASTP for collinearity detection
diamond makedb --in combined_proteomes.fa -d combined_db
diamond blastp -d combined_db -q combined_proteomes.fa -o all_vs_all.blast -e 1e-10 --max-target-seqs 5 -p 16

# 2. Identify syntenic collinear blocks with MCScanX
MCScanX species_comparison

# 3. Plot macrosynteny karyotype ribbons using JCVI
python -m jcvi.compara.catalog ortholog tomato_v1 potato_v1 --no_strip_names
python -m jcvi.graphics.karyotype seqids layout
Chapter 09 PAN-GENOMES • STRUCTURAL VARIANTS

09. Plant Pan-Genomics & Structural Variant Graphs (PGGB / SyRI)

Single reference genomes miss accessory genes controlling disease resistance ($NLR$ clusters) and abiotic stress tolerance. Construct chromosome-level variation graphs and call inversions, translocations, and PAVs.

Tools: PGGB, Minigraph-Cactus, vg toolkit, SyRI, plotsr Output: Pan-genome graph (GFA/VCF), Core vs. Dispensable gene catalog Spec: 32 CPU Cores • 64–128 GB RAM
# 1. Build an all-to-all chromosome pan-genome graph across 8 accessions using PGGB
pggb -i chr01_8_accessions.fa.gz \
  -p 95 \
  -s 10000 \
  -n 8 \
  -t 32 \
  -V 'ref_cultivar:#' \
  -o chr01_pangenome_graph

# 2. Call chromosomal inversions, translocations & PAVs between two assemblies with SyRI
minimap2 -ax asm5 --eqx -t 16 ref_genome.fa query_genome.fa | samtools sort -o asm_align.bam
syri -c asm_align.bam -r ref_genome.fa -q query_genome.fa -F B --prefix cultivar_vs_wild_
plotsr --sr cultivar_vs_wild_syri.out --genomes genomes.txt -o structural_variants_chr.pdf
Chapter 10 POPULATION GENETICS • SWEEPS

10. Population Genetics, Selective Sweeps & Domestication (Pixy)

Standard VCFtools nucleotide diversity ($\pi$) calculations are systematically biased downward when missing genotypes and invariant sites are excluded. Use all-sites VCFs with Pixy to accurately scan for domestication sweeps.

Tools: Pixy, ADMIXTURE, IQ-TREE, XP-CLR Output: Unbiased sliding-window π, Fst, dXY + Selective sweep peaks Spec: 16 CPU Cores • 32 GB RAM
# 1. Index an all-sites VCF (containing both variant and invariant/monomorphic sites)
tabix -p vcf crop_panel_allsites.vcf.gz

# 2. Compute unbiased sliding-window Pi, Fst, and dXY between Wild vs. Cultivated groups
pixy --stats pi fst dxy \
  --vcf crop_panel_allsites.vcf.gz \
  --populations pop_assignments.txt \
  --window_size 50000 \
  --n_cores 16 \
  --output_folder pixy_domestication_scan
Chapter 11 CROP GWAS • MIXED MODELS

11. Crop GWAS & Mixed Linear Models (GAPIT 3 / GEMMA)

Control for false positives induced by population stratification ($Q$) and cryptic relatedness/kinship ($K$) in structured breeding panels using multi-locus models (BLINK and FarmCPU).

Tools: GAPIT 3, GEMMA, TASSEL, plink2 Output: Manhattan & QQ plots, FDR-adjusted significant trait-associated SNPs Spec: 16 CPU Cores • 32 GB RAM
# R Production Script: Multi-Locus GWAS using GAPIT 3 (BLINK & FarmCPU)
library(GAPIT)

myY <- read.table("phenotypes_yield_drought.txt", head = TRUE)
myG <- read.delim("hapmap_filtered_maf005.hmp.txt", head = FALSE)

myGAPIT <- GAPIT(
  Y = myY[, c(1, 2)],          # Taxa ID + Trait column
  G = myG,                     # HapMap genotype matrix
  PCA.total = 3,               # Top 3 PCs for population structure (Q)
  model = c("MLM", "FarmCPU", "BLINK"),
  Multiple_analysis = TRUE
)
Chapter 12 QTL-SEQ • BULKED SEGREGANTS

12. QTL-Seq & Bulked Segregant Analysis (QTLseqr)

Rapidly map causal loci in $F_2$ or RIL mapping populations by sequencing only two extreme phenotypic pools (e.g., Resistant Bulk vs. Susceptible Bulk, 30–50 plants per pool) and computing $\Delta(\text{SNP-index})$ and the $G'$ statistic.

Tools: QTLseqr, GATK VariantsToTable Output: Sliding-window Δ(SNP-index) & G' statistic peak plots pinpointing causal QTL Spec: 8–16 CPU Cores • 16–32 GB RAM
# R Production Script: Sliding-Window Δ(SNP-index) and G' Analysis with QTLseqr
library(QTLseqr)

df <- importFromGATK(
  file = "bsa_bulks_gatk.table",
  highBulk = "Resistant_Bulk",
  lowBulk = "Susceptible_Bulk"
)

df_filt <- filterSNPs(
  SNPset = df,
  refAlleleFreq = 0.20,
  minTotalDepth = 40,
  maxTotalDepth = 250,
  minSampleDepth = 20
)

df_qtl <- runQTLseqAnalysis(df_filt, windowSize = 1e6, popStruc = "F2", bulkSize = c(40, 40), replications = 10000)
df_qtl <- runGprimeAnalysis(df_qtl, windowSize = 1e6, outlierFilter = "deltaSNP")
plotQTLStats(SNPset = df_qtl, var = "deltaSNP", plotIntervals = TRUE)
Chapter 13 GENOMIC SELECTION • PLASTOMES

13. Genomic Selection (rrBLUP) & Organellar Genomes (GetOrganelle)

Predict Genomic Estimated Breeding Values (GEBVs) across unphenotyped breeding lines using Ridge Regression Best Linear Unbiased Prediction (rrBLUP), and assemble complete circular chloroplast/mitochondrial genomes from whole-genome shotgun reads.

Tools: rrBLUP, BGLR, GetOrganelle Output: GEBV breeding predictions & Circular plastome FASTA Spec: 16 CPU Cores • 32 GB RAM
# Assemble circular Chloroplast genome directly from WGS Illumina reads
get_organelle_from_reads.py \
  -1 wgs_R1.fq.gz -2 wgs_R2.fq.gz \
  -o plastome_out \
  -R 15 -k 21,45,65,85,105 \
  -F embplant_pt \
  -t 16
SANDBOX ARCHIVES FAIR • CC BY 4.0

📦 Subsampled Practice Datasets (/resources/datasets/plant-genomics/)

Self-contained, real-world subsampled matrices paired with expected outputs to test pipelines on standard workstations before running large-scale HPC nodes.

Dataset ArchiveFile SizeDescription & Included Truth SetTarget Chapters
solanum_chr1_mini_hifi.fq.gz85 MB15x coverage PacBio HiFi reads for a 2 Mb pericentromeric + euchromatic region of Tomato Chr01.Ch 01, 02, 04
solanum_chr1_RepeatMasker.fa2.1 MBPre-assembled 2 Mb contig enriched in Gypsy and Copia LTR retrotransposons.Ch 05, 06, 07
crop_diversity_200lines.vcf.gz14 MB200 accessions × 50,000 biallelic SNPs + simulated agronomic traits (fruit_weight, brix, salt_tolerance).Ch 10, 11, 13
bsa_blight_bulks_gatk.tsv3.4 MBGATK VariantsToTable allele depth table for Resistant vs. Susceptible $F_2$ bulks showing a major QTL peak on Chr06.Ch 12