1. Floral and aromatic analysis of the soybean perennial Glycine syndetika for
future agronomic exploitation
Allison L. Pappas1, Jacek A. Koziel2, Rosanne A. Healy3, Harry T. Horner4, Ted B. Bailey5, Anthony H. D. Brown6 and Reid G. Palmer7
1,7USDA-ARS Crop Insects and Crop Genetics Research Unit (CICGR), Ames, Iowa 50011, USA
2Department of Agricultural & Biosystems Engineering, Iowa State University, Ames, Iowa 50011, USA
3,4Department of Genetics, Development and Cell Biology and Microscopy and NanoImaging Facility, Iowa State University, Ames, Iowa 50011, USA
5Department of Statistics, Iowa State University, Ames, Iowa 50011, USA
6CSIRO Plant Industry, Canberra, ACT 2601, AU
7Department of Agronomy, Iowa State University, Ames, Iowa 50011, USA
Abstract
The insect-mediated outcrossing frequencies observed in wild peren-
nial soybean species (>50%) is one of potentially many traits that repre-
sent an agronomically important resource for enhancing the cultivated
annual soybean Glycine max (<1% outcrossing) germplasm and devel-
oping commercial hybrid soybean cultivars. Glycine syndetika (G 1300)
is a perennial species noteworthy for its relatively intense perfume;
while the annual Glycine max has little detectable smell, G. syndetika’s
aromatics can easily infuse an entire room. Volatile compounds re-
leased by G. syndetika flowers were collected using the non-invasive
technique of solid phase microextraction and were analyzed by gas
chromatography-mass spectrometry-olfactometry. Several volatile or-
ganic compounds were identified, with the most pungent odors includ-
ing sweet, fruity, and mushroom notes. Glycine syndetika was also
sampled and analyzed for sugar content of its nectar. Finally, image
analyses were carried out on developing nectaries of G. syndetika, G.
soja (wt) and three annual cultivars (Raiden, Beeson and Wells) to de-
termine subcellular differences, and to compare them with the volatile
and sugar data. These combined results should contribute to a more
comprehensive catalog of G. syndetika’s characteristics that can be ex-
ploited to genetically enhance annual soybean cultivars.
Early bud
formation
Anthesis
Development of G. syndetika nectaries
Progression of G. syndetika
nectaries from early devel-
opment through anthesis as
visualized by scanning elec-
tron microscopy (SEM). The
left SEM panels show the
entire nectary while the
right SEM panels allow for
visualization of the corre-
sponding cellular morphol-
ogy. All images were ac-
quired with a JEOL 5800LV
scanning electron micro-
scope at 15kV.
A G. syndetika raceme
Nectar sugar content of G. syndetika
Sugar Plant # Average Amount (n=3)
Fructose 1
2
158 ± 11.7
114 ± 10.7
Sucrose 1
2
313 ± 6.85
245 ± 21.7
Glucose 1
2
88.7 ± 3.27
55.8 ± 2.95
Plant # Sucrose:Fructose:Glucose Ratio
1 3.53 : 1.78 : 1
2 4.39 : 2.05 : 1
Average sugar amounts were determined using a
spectrophotometric assay for two separate plants.
Measurements were taken from three different
flowers on each plant.
Aromagram
peak #
Start
Time
(min)
Smell
Description
Retention
Time (min)
Compound
Identity
Probability
1 2.61 Rancid 2.5903 Pentane 85%
4 5.8 Plastic 5.7672
1-Penten-3-
one
62%
5 6.83 Sweet, Fruity 6.87
Butanoic acid,
2-methyl-,
methyl ester
91%
6 8.04 Herbaceous 7.97 Hexanal 94%
9 12.59 Buttery 12.83 3-Octanone 78%
10 13.01 Mushroom 13.42
6-Octen-2-
one
79%
Identification of volatile organic compounds emitted by G. syndetika flowers
Gas chromatography-mass spectrometry-olfactometry (GC-MS-O) workflow
Solid-phase microextraction
(SPME) of volatile organic
compounds (VOCs)
Injection of SPME fiber
into GC-MS-O (release
of VOCs)
Gas chromatography
of VOCs
Mass spectrometry
of VOCs (chromatogram)
Olfactometric
characterization of VOCs
by nose (aromagram)
MS chromatogram (red) and olfactometry aromagram (black) of G. syndetika
flowers. Volatile organic compounds (VOCs) were extracted by solid phase
microextraction (SPME) at 35o
C for 4.5 hours. The SPME fiber was then in-
jected into the GC-MS-O system for simultaneous compound and scent iden-
tification. The experiment was repeated eight times using flowers from two
different plants. The table contains select aromas and their VOC identity that
are emitted by G. syndetika flowers as determined from the GC-MS-O results
on the right.
Olfactometry results MS results
We would like to gratefully acknowledge the Biotechnology Research and
Development Corporation for their financial support of this project.
Acknowledgements
Rancid
Rancid
Solvent
Plastic
Sweet, Fruity
Herbaceous
Grassy
Sweet, Floral
Buttery
Mushroom
Herbaceous, Floral
Sweet, Fruity
Neutral
Fecal
Floral
Neutral
Herbaceous
Herbaceous, Buttery
Unpleasant
Mint
Oatmeal
Time (minutes)
RelativeIntensity
1
4
5
6
9
10