Fighting Plants
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Transcript of Fighting Plants
Fighting Plants
Lieceng Zhu, PhDDepartment of Biological Sciences
Fayetteville State University
Plants Are Amazing!
Being Plants Are No Fun
Biotic Stress • Pathogens• Herbivores
Abiotic Stress
Run away?
No Fly, Fight or Die
Plant Defense
Ways & Means
• Cry for help• Talk and listen• Memory
• Chemical• Physicals
• Antibiosis• Antixenosis• Tolerance
• Local • Systemic
• Constitutive • Induced
Cry for Help
• The enemies of enemies are friends
Warn Friends & Neighbors/Talk & listen
Ian T. Baldwin, et al. 2006.Science (311) 812-815
Remember the Offense
Not forgotten, nor forgiven
Antixenosis(Deter or prevent)
• Physical: Trichome• Chemical: Smell/taste
AntibiosisAffect development & reproduce
• Toxic compounds• Less nutritive
ToleranceYou have your way, I have my way!
Chemical Defense
• Secondary metabolites– Alkaloids: Nicotine,
cocaine– Terpene (GLV)– Phenolics: Pyrethrin
Physical Defense
Constitutive & Induced Defense
Steps of Induced Defense Responses
• Perceive: Insect oral secretion
• Transduce signal: secondary messenger (Phytohormones)
• Defense response
Phytohormones & Fatty Acids
• Jasmonic acid (JA)• Salicylic acid (SA)• abscisic acid (ABA)• Auxin (IAA)• 12-Oxo-Phytodienoic Acid (OPDA)• Fatty acids
– Oleic acid (FA18:1)– Linolenic acid (FA18:3)
The Tale of Wheat & Hessian Fly
• Host & Parasite• Life & death
Wheat (Tricitcum aestivum)
• # 6• # 3 • # 3, 20% calories.
eggs on leaf
larvae pupae
adult
Hessian Fly (HF) (Mayetiola destructor)
• A family of Mosquito
• Asian-Europe-North American– Independent war
• Destructive
Wheat - Hessian fly Interaction
Host & parasite Life & death• larvae stage• Sessile• Inject toxin• Stunt & Kill
Resistant & Susceptible Plants in Fields
•
Resistant (A) and susceptible (B) wheat cultivars in Benton Co. MO, Dec. 2005. Photos: B. Schemerhorn, J. Stuart.
Wheat - Hessian Fly InteractionA gene for gene model
Incompatible Compatible
Avirulent Virulent
Control
vH13GP
Objective of Research
• Identify plant hormones related to resistance/susceptibility of of wheat to Hessian fly infestation
Significance
• Understand the molecular mechanism of plant resistance
• Develop cultivars with durable resistance
• Protect food & agriculture security
Materials & Methods
• Plant & insects• Infesting• Sampling• Phytohormone profiling
Plants
• Wheat Molly: At two leaf stage
Insects • Biotype GP (avirlulent) and vH13
(virulent)
Experiment Design
Genotype 24 H 72 H
CK CKMolly R (GP) R (GP)
S (vH13) S (vH13)
•5 reps
Infestation
Avirulent GP
Control (CK)
Incompatible (S)
Compatible (S)
Virulent vH13
How to infest?
•15 HF/pot
After Infestation
SamplingAvirulent
Control (CK)
Incompatible (S)
Compatible (S)
Virulent
Phytohormone Profiling
GC-MS Analysis
Gas Chromatography
DetectorSeparator
Mass Spectrometry
• Determine concentration of several types of phytohormone simultaneously
Results & Discussions
Phytohormone Profiling• 10 phytohormone/related compounds detected
IAA, SA, CA, BA, JA, OPDA, 18:3, 18:1, 18:2 & 18:0 FA
• IAA, SA, JA, OPDA, 18:1, 18:3 were affected at feeding sites
Avirulent
Control (CK) Incompatible (S) Compatible (S)
Virulent
Data file
• Excel file• Statistics: • Means – standard deviation– standard error– Chart
Compatible Interaction
• IAA increased– Major form of Auxin
• Implication: IAA contributes to susceptibility
0
50
100
150
200
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24H 72H
Mea
n ±S
E (n
g/g
fres
h w
eigh
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IAA CRS
Incompatible Interaction• SA & OPDA increased
– Concentration (ng/ g fresh weight)
11 fold
8 fold
35 fold
18 fold
SA OPDA
18:3 FA
Membrane lipids
LOX2
AOS
AOC
OPDA
OPR3
JA
Response • 18:3 & 18:1 FA increased• JA decreased at 24 H• Implication:– JA may not regulate resistance– OPDA & SA may regulate resistant responses
Conclusion
• OPDA & SA may act together in wheat resistance to HF• IAA plays a role in susceptibility of wheat plants
• Zhu et al. JEE, (103) 178-185
The End