Approaches to subspecies diagnostics in big sagebrush
(Artemisia tridentata) using an Electronic Nose
Hector Ortiz, Bryce Richardson
USFS-Rocky Mountain Station, Chicago Botanic
Garden
The Chemical Species Profile Discrimination
(A Brief Description)
• Smell receptor
• Chemosensors
• Odor sensing,
e-nose
applications
• Smell profiles
Big Sagebrush Emission of HIPV’s, GLV’s, VOC’s
- High Sensitivity to Light and Temperature
- Herbivore Selection Pressure, caused speciation?
- Insects
Camphene
Arthole
1,8-Cineole
Methy Santolinate
Camphor
Methacrolein
or methacroldehyde
Molecular formula C4H6O
Aerial interaction of the wild tabacco Nicotiana
atenuata and sagebrush Artemisia tridentata.
Baldwing et, al. 2006
Objectives
• Determinate sensitivity to known plant
volatiles (methacrolein)
• Develop an standard protocol for volatile
analysis
• Assess effectiveness at discriminating
subspecies
PC-Nose Standardization
• Parameterization with pure methacrolein
• Sensor selection
• Train E-Nose with Artemisia samples
Sample Preparation
1. Collect and freeze fresh
leaves
2. Crush and elute with water
3. Centrifuge
4. Program the settings of the
PC Nose
5. Training and sample analysis
Cross Validation
Methacrolein Method
Trained As
Identified As
Methacroleine
10%
20%
50%
70%
80%
10%
8
0
0
0
0
20%
0
8
0
0
0
50%
0
0
8
0
0
70%
0
0
0
8
0
80%
0
0
0
0
8
Correct: 100%
Results
• First analysis shows, how the volatile profiles within
and between samples of the same subspecies are
related
- These samples were collected from a common garden
• Second analysis shows differences among
subspecies (tridentata, vaseyana and
wyomingensis)
• Third analysis was a comparison between
subspecies within a small geographic range
Canonical Projection Plot
first analysis—within subspecies and individual
variation, A. tridentata
NVT-2
MTT-1
WAT-1
ORT-3
Putative
hybrid
NVT-1
IDT-3
Variation within samples
A. tridentata
Potential hybrid
20.0
M- Distance
15.0
10.0
5.0
0.0
WAT-1
ORT-3
NVT-2
NVT-1
MTT-1
IDT-3
Canonical Projection Plot
first analysis—within subspecies and individual
variation, A. vaseyana
IDV-3
Putative
hybrid
IDV-2
IDV-4
MTV-1
CAW-3
UTV-1
Variation within samples
A. vaseyana
Potential hybrid
25.0
M-Distance
20.0
15.0
10.0
5.0
0.0
MTV-1
IDV-4
IDV-3
IDV-2
CAW-3
UTV-1
Canonical Projection Plot
A. wyominensis
MTW-1
COW-2
IDW-2
IDW-3
MTW-3
UTV-2
Variation within samples
A. wyomingensis
35.0
M-Distance
30.0
25.0
20.0
10.0
5.0
0.0
MTW-1
UTV-2
COW-2
IDW-2
IDW-3
MTW-1
Second analysis comparison among
A. tridentata, A. vaseyana, A. wyomingensis
Factor 2
10.0
5.0
A. wyomingensis
A. tridentata
0.0
-5.0
A. vaseyana
-10.0
-5.0
0.0
5.0
10.0
Factor 1
15.0
20.0
25.0
30.0
Comparison between subspecies within a small
geographic range (<15km)
Location: La Sal, Utah
wyomingensis
UTW-1
10.0
vaseyana
UTV-3
Factor 2
5.0
0.0
tridentata
UTT-1
-5.0
-10.0
-25.0
-20.0
-15.0
-5.0
Factor 1
-10.0
0.0
5.0
10.0
15.0
On Going Work
• Other factors under
consideration:
• Environment
• Time of year
• Stems, seeds and flower parts?
Summary
• The e-nose can detect presence or absence of
VOC’s, and different concentrations of
methacrolein
• The protocol developed appears to capture the
important volatiles involved in distinguishing
subspecies
• The e-nose was capable of differentiating
subspecies from a common environment