Automated DNA Library Prep | Metagenomic Sequencing for Rhizosphere Microbiome

The rhizosphere microbiome — the microbial community surrounding plant roots — governs nutrient cycling, plant health and stress resilience. Metagenomic sequencing of DNA extracted from rhizosphere soil resolves community structure and diversity, functional potential and metabolic pathways, even the genomes of uncultured members, and supports multi-omics integration, rhizosphere engineering and agro-translational research.

This application note establishes an automated metagenomic library-construction workflow for plant rhizosphere soil DNA on the MGISP-960 platform with the Hieff NGS™ OnePot Pro DNA Library Prep Kit V4 (12972ES). The workflow supports inputs as low as 10 ng and delivers Illumina-compatible libraries, turning “based on experience” into “based on standard” for cross-site ecology studies.

Background and Pain Points

Soil-derived metagenomic material stresses every step of library construction, and the manual route amplifies each difficulty:

•  Low input: 10–25 ng of soil DNA leaves little margin for handling loss.

•  Inhibitor risk: humic substances co-extracted from soil suppress enzymatic reactions — input QC is critical.

•  Community complexity: diverse microbiomes need unbiased, even library representation to reflect true abundance.

•  Cross-site comparability: multi-location ecology studies demand strict batch-to-batch consistency that only programmed handling provides.

Application Scenarios

From diversity profiling to rhizosphere engineering, the automated workflow covers the full metagenomics question space.

Figure 1. Application landscape covered by the automated rhizosphere metagenomic library-construction workflow.

The Automated Workflow

The protocol runs on the MGISP-960 with the OnePot Pro DNA Library Prep Kit V4 (12972ES) and Illumina-compatible PE adapters. One 96-sample run consumes 8 deep-well plates, 6 PCR plates and 7 boxes of filtered tips.

Figure 2. Automated rhizosphere metagenomic library-preparation workflow on the MGISP-960 (Illumina library).

Reagent List for the Experiment

Category	Cat.No.	Product name
DNA Library Preparation	12972ES	Hieff NGS™ OnePot Pro DNA Library Prep Kit V4
Magnetic Beads	12601ES	Hieff NGS™ DNA selection Beads (Superior Ampure XP alternative)
Quantification	12642ES	1× dsDNA HS Assay Kit dsDNA qubit
Adapters	12327–12330ES	Hieff NGS™ Stubby UDI Primer Kit for Illumina, Set 1
Automation Consumables	83560ES / 83672ES / 83130ES	0.2 mL 96-well PCR plates (white, full skirt) / 96-deep-well plates (U-bottom, 1.3 mL) / 250 μL filtered sterile tips
Sealing	83624ES	qPCR pressure-sensitive sealing film (scraper included)
User-Supplied Materials	—	Absolute Ethanol

Pre-Experiment Preparation

•  Equilibrate DNA Selection Beads to room temperature for at least 30 minutes and resuspend fully before deck loading.

•  Prepare fresh 80% ethanol for all bead washes.

•  Keep the PE adapter working solution at 2 μM (manual pre-step, keep on ice).

•  Load 8 deep-well plates, 6 PCR plates and 7 boxes of filtered tips for one 96-sample run; confirm deck layout and liquid volumes.

•  QC the soil DNA input (purity and fragment length) before the run — humic contamination directly suppresses ligation efficiency.

Experimental Tips

Sample & input

•  The workflow is validated at 10 ng and 25 ng inputs; keep the chosen mass consistent across the plate.

•  Further purify soil DNA when humic-acid contamination is suspected — inhibitors are the top cause of low-yield metagenomic libraries.

Bead-based purification & size selection

•  Post-ligation purification uses 0.6× beads (66 μL) eluted in 104 μL; size selection at 0.60×/0.15× follows, with 22 μL elution and 20 μL transferred to PCR.

•  Avoid over-drying beads; cracked pellets reduce recovery, which is costly at 10 ng input.

Adapter handling & PCR

•  PE adapter at 2 μM with 20°C 15-minute ligation is the validated low-input setting.

•  11 PCR cycles with 5 μL index primer balance yield and duplication for 10–25 ng inputs.

Automation & QC

•  Follow the 12972ES IFU scripts exactly; the low-input program (4°C 1 min → 30°C 12–15 min → 72°C 20 min) is part of the validated package.

•  Quantify with the 1× dsDNA HS Assay Kit and confirm a sharp single peak on the electropherogram before pooling.

Experimental Conditions and Results

Validated QC results: 1,053 ng total yield from the 10 ng input and 2,620 ng from the 25 ng input — yield scales proportionally with input, and final libraries show a sharp single peak on the electropherogram, meeting sequencing-ready specifications.

Figure 3. Rhizosphere microbiome library yield at 10 ng versus 25 ng input.

Analysis of Experimental Results

Libraries were constructed from DNA extracted from plant rhizosphere soil using the enzymatic fragmentation library‑prep kit 12972ES. High library yield and tight fragment‑size distribution were achieved, which meets standard quality‑control criteria.