Amplicon Sequencing
Aaron Marc Saunders

Introduction To Community Systems Microbiology, Aalborg 2013
Introduction To Community Systems Microbiology, Aalborg 2013
Bacterial diversity
Phylum Actinobacteria
Genus Tetrasphaera

cultured representative
Introduction To Community Systems Microbiology, Aalborg 2013
Environmental diversity

DNA extraction

Environmental sample

mixed genomic DNA

Introduction To Community Systems Microbiology, Aalborg 2013
Environmental surveys
●

Marker gene Sequencing
–
–

●

PCR product
One gene fragment

Metagenomics
–

Total DNA

–

All genes

Introduction To Community Systems Microbiology, Aalborg 2013
Marker Genes

Introduction To Community Systems Microbiology, Aalborg 2013
http://fungene.cme.msu.edu/
”Tree of Life”

Introduction rRNA gene
Based on 16S To Community Systems Microbiology, Aalborg 2013
Start
Stop

Introduction To Community Systems Microbiology, Aalborg 2013
Hypervariable regions
E. coli

All life!

V4
Introduction To Community Systems Microbiology, Aalborg 2013
16S rRNA gene conservation

Regions denoted ”hypervariable”

http://www.bioinformatics-toolkit.o

Introduction To Community Systems Microbiology, Aalborg 2013
Environmental surveys
mixed genomic DNA

Environmental sample

PCR product

16S clone library

Introduction To Community Systems Microbiology, Aalborg 2013
Introduction To Community Systems Microbiology, Aalborg 2013
Environmental surveys
mixed genomic DNA

metagenomic
NGS sequencing
library

Environmental sample

PCR product

amplicon library

Introduction To Community Systems Microbiology, Aalborg 2013
Amplicon vs. Metagenomics
–

less complex
●
●

–
–

extensive database
same fragment
●

–
–
–

better coverage
more samples

comparable phylogenetic info

PCR bias
Limited phylogenetic info
(genus/species level)
Limited functional information

Introduction To Community Systems Microbiology, Aalborg 2013
Typical results
Small number of highly abundant species and a long tail of rare species

Introduction To Community Systems Microbiology, Aalborg 2013
2. methodology

Introduction To Community Systems Microbiology, Aalborg 2013
16S rRNA amplicon
sequencing
Sample
PCR
”Short” PCR product (70-400 bp)
Next-gen sequencing
Sequence reads
Quality screen and clustering
Sequence types (OTUs)
Matching to existing database
Classified OTUs
Introduction To Community Systems Microbiology, Aalborg 2013
16S rRNA amplicon
sequencing
Sample
PCR
”Short” PCR product (70-400 bp)
Next-gen sequencing
Sequence reads
Quality screen and clustering
Sequence types (OTUs)
Matching to existing database
Classified OTUs
Introduction To Community Systems Microbiology, Aalborg 2013
Environmental surveys
DNA extraction

mixed genomic DNA
Environmental sample

PCR product

amplicon library

Introduction To Community Systems Microbiology, Aalborg 2013
Hypervariable regions

V4

E. coli

All life!

Introduction To Community Systems Microbiology, Aalborg 2013
PCR product

454 = 400 bp
Illumina = 250 bp

Examples of NGS sequenced amplicons
http://www.bioinformatics-toolkit.o
Regions denoted ”hypervariable”
Introduction To Community Systems Microbiology, Aalborg 2013
Multiplexing
Normal PCR product

NGS-adapted PCR product

Barcoded PCR product for NGS

Introduction To Community Systems Microbiology, Aalborg 2013
Multiplexing
adaptor

barcode Primer sequence

Amplified sequence

…GCCATCAG GATCT CNACGCGAAGAACCTTANC NNNNNNNNNN…
Sample 1
…GCCATCAG ATCAG CNACGCGAAGAACCTTANC NNNNNNNNNN…
Sample 2
…GCCATCAG CACTG CNACGCGAAGAACCTTANC NNNNNNNNNN…
Sample 3
…GCCATCAG CTGTG CNACGCGAAGAACCTTANC NNNNNNNNNN…
Sample 4

Introduction To Community Systems Microbiology, Aalborg 2013
16S rRNA amplicon
sequencing
Sample
PCR
”Short” PCR product (70-400 bp)
Next-gen sequencing
Sequence reads
Quality screen and clustering
Sequence types (OTUs)
Matching to existing database
Classified OTUs
Introduction To Community Systems Microbiology, Aalborg 2013
Bacterial Diversity

Introduction To Community Systems Microbiology, Aalborg 2013
Clustering

Representative sequence

Introduction To Community Systems Microbiology, Aalborg 2013
Consider Errors!
• Low quality reads
• PCR errors
• Sequencing errors
–

Particularly homopolymers
●

454 & ion torrent!

• Chimeras

Introduction To Community Systems Microbiology, Aalborg 2013
16S rRNA amplicon
sequencing
Sample
PCR
”Short” PCR product (70-400 bp)
Next-gen sequencing
Sequence reads
Quality screen and clustering
Sequence types (OTUs)
Matching to existing database
Classified OTUs
Introduction To Community Systems Microbiology, Aalborg 2013
Functional information
• Isolates
• Functional 16S rRNA work
–

Stable isotope probing

• Metagenomics
• In situ studies
–
–
–

Microscopy – eg. inclusion bodies
Microautoradiography
Raman or NanoSIMS

Introduction To Community Systems Microbiology, Aalborg 2013
Taxonomic assignment
Genus A

Family

Genus B

Genus C

Introduction To Community Systems Microbiology, Aalborg 2013
Taxonomic assignment
Genus A

Family

Genus B

Genus C

Introduction To Community Systems Microbiology, Aalborg 2013
Taxonomic assignment
Genus A

Family

Genus B

Genus C

Introduction To Community Systems Microbiology, Aalborg 2013
Taxonomic assignment
Genus A

Family

Genus B

Genus C

Introduction To Community Systems Microbiology, Aalborg 2013
Using a ”Classifier”
• Uses an existing phylogeny
• Find best unambiguous match to
references

Introduction To Community Systems Microbiology, Aalborg 2013
Classification results

Introduction To Community Systems Microbiology, Aalborg 2013
Microautoradiography
Radioac
tive
phospha
te

Accumulibacter
Radioactive Aalborg 2013
Introduction To Community Systems Microbiology,acetate
Other Bacteria
Metagenomics

Simon McIllroy, Microthrix
ISME J 7 (6): 1161
Introduction To Community Systems Microbiology, Aalborg 2013
Substrate specificity
Accumulibacter

Tetraspheara

Competibacter

Defluvicoccus

acetate

+

-

+

+

propionate

+

-

-

+

Casamino
acids

Glu only

+

-

-

Nitrate
reduction

+/-

+/-

+/-

-

Determined by FISH-MAR

Introduction To Community Systems Microbiology, Aalborg 2013
Greengenes assignment
species
(OTU)
OTU1

Class

Order

Betaproteobacteria Nitrosomonadales

Family

Genus

Nitrosomonadacea
Nitrosomonas
e

OTU2

Nitrospira

Nitrospirales

Nitrospiraceae

Nitrospira

OTU3

Betaproteobacteria

Rhodocyclales

Rhodocyclaceae

Propionivibrio

OTU4

Betaproteobacteria

Gallionellales

Gallionellaceae

??

OTU5

Gammaproteobacte
ria

??

??

??

Introduction To Community Systems Microbiology, Aalborg 2013
midasfieldguide.org

midasfieldguide.org

52 core genera
64% organisms DK
41% globally
+ others

Introduction To Community Systems Microbiology, Aalborg 2013
MIDAS curated assignment
species
(OTU)

Class

Order

Family

Genus

OTU1

Betaproteobacteria

Nitrosomonadales

Nitrosomonadaceae

Nitrosomonas

OTU2

Nitrospira

Nitrospirales

Nitrospiraceae

Nitrospira

OTU3

Betaproteobacteria

Rhodocyclales

Rhodocyclaceae

Accumulibacter

OTU4

Betaproteobacteria

Gallionellales

Gallionellaceae

Nitrotoga

OTU5

Gammaproteobacteria Competibacterales Competibacteraceae

Competibacter

Introduction To Community Systems Microbiology, Aalborg 2013
Percent abundance

Nitrite-oxidisers
0.3

genus

0.2

0.1

0

Introduction To Community Systems Microbiology, Aalborg 2013
Analysis Tools
●

Qiime (qiime.org)

●

Mothur (mothur.org)

●

R (r-project.org)
–

Phyloseq package
(http://joey711.github.io/phyloseq/)

Introduction To Community Systems Microbiology, Aalborg 2013
●

Analysis Example

●

●

http://nbviewer.ipython.org/7213441

Introduction To Community Systems Microbiology, Aalborg 2013
Comparing Bacterial diversity of Wastewater and activated sludge
Location

Sample type

Replicate

Aalborg East

activated sludge

AAE-1

Aalborg East

activated sludge

AAE-2

Aalborg East

wastewater

AAE-1

Aalborg East

wastewater

AAE-2

Aalborg West

activated sludge

AAW-1

Aalborg West

activated sludge

AAW-2

Aalborg West

wastewater

AAW-1

Aalborg West

wastewater

AAW-2

Hjoerring

activated sludge

HJO-1

Hjoerring

activated sludge

HJO-2

Hjoerring

wastewater

HJO-1

Hjoerring

wastewater

HJO-2

Introduction To Community Systems Microbiology, Aalborg 2013
Phylum level Classification

Proteobacteria
Firmicutes
Bacteroidetes

AS
WW
Introduction To Community Systems Microbiology, Aalborg 2013
Genus level Classification

AS

WW

Introduction To Community Systems Microbiology, Aalborg 2013
Alpha Diversity

• How diverse is the community in my
sample?
• Richness
– How many organisms are in my
sample?
• Evenness
– How evenly are they distributed?

Introduction To Community Systems Microbiology, Aalborg 2013
Richness estimates

Introduction To Community Systems Microbiology, Aalborg 2013
Introduction To Community Systems Microbiology, Aalborg 2013
Beta Diversity

• How similar/different is my sample
from other samples?

Introduction To Community Systems Microbiology, Aalborg 2013
Clustering

Introduction To Community Systems Microbiology, Aalborg 2013
Principal components analysis

Introduction To Community Systems Microbiology, Aalborg 2013
Label with environmental data

Introduction To Community Systems Microbiology, Aalborg 2013
Amplicon Sequencing
• Pros:
–
–

”cheap”, many samples
16S: good database for classification

• Cons:
–
–

PCR and primer bias
limited functional information

Introduction To Community Systems Microbiology, Aalborg 2013

Amplicon Sequencing Introduction

Editor's Notes

  • #17 Roche is supposed to soon come with a 1000 bp sequencer <number>
  • #22 <number>
  • #23 <number>
  • #24 Mantoin the concept with the large fragments and matching <number>
  • #27 Quince 30-50% overestimation of OTUs <number>
  • #28 Mantoin the concept with the large fragments and matching <number>
  • #39 Figure: Nitrotoga, a newly-discovered genus of nitrite-oxidisers, was found to be core in EPPR plants and in >1% in some. They are therefore likely making a significant contribution to nitrite oxidiation in these plants. <number>
  • #41 Figure: Nitrotoga, a newly-discovered genus of nitrite-oxidisers, was found to be core in EPPR plants and in >1% in some. They are therefore likely making a significant contribution to nitrite oxidiation in these plants. <number>
  • #42 Figure: Nitrotoga, a newly-discovered genus of nitrite-oxidisers, was found to be core in EPPR plants and in >1% in some. They are therefore likely making a significant contribution to nitrite oxidiation in these plants. <number>