510 likes | 680 Views
Fighting Plants. Lieceng Zhu, PhD Department 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
E N D
Fighting Plants Lieceng Zhu, PhD Department of Biological Sciences Fayetteville State University
Biotic Stress • Pathogens • Herbivores
Ways & Means • Cry for help • Talk and listen • Memory • Chemical • Physicals • Local • Systemic • Antibiosis • Antixenosis • Tolerance • 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
Chemical Defense • Secondary metabolites • Alkaloids: Nicotine, cocaine • Terpene (GLV) • Phenolics: Pyrethrin
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 (Tricitcumaestivum) • # 6 • # 3 • # 3, 20% calories.
Hessian Fly (HF) (Mayetiola destructor) • A family of Mosquito • Asian-Europe-North American • Independent war • Destructive adult eggs on leaf pupae larvae
Wheat - Hessian fly Interaction • Host & parasite • Life & death • larvae stage • Sessile • Inject toxin • Stunt & Kill
Resistant (A) and susceptible (B) wheat cultivars in Benton Co. MO, Dec. 2005. Photos: B. Schemerhorn, J. Stuart. Resistant & Susceptible Plants in Fields
Wheat - Hessian Fly Interaction A gene for gene model vH13 Virulent GP Avirulent Incompatible Control Compatible
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 • 5 reps
Infestation Virulent vH13 AvirulentGP Control (CK) Incompatible (S) Compatible (S)
How to infest? • 15 HF/pot
Sampling Virulent Avirulent Control (CK) Incompatible (S) Compatible (S)
Phytohormone Profiling GC-MS Analysis • Determine concentration of several types of phytohormone simultaneously Gas Chromatography Mass Spectrometry Detector • Separator
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 Virulent Avirulent Control (CK) Incompatible (S) Compatible (S)
Data file • Excel file • Statistics: • Means • standard deviation • standard error • Chart
Compatible Interaction • IAA increased • Major form of Auxin • Implication: IAA contributes to susceptibility
Incompatible Interaction • SA & OPDA increased • Concentration (ng/ g fresh weight) 11 fold SA 8 fold OPDA 35 fold 18 fold
Membrane lipids 18:3 FA LOX2 AOS AOC OPDA OPR3 JA • 18:3 & 18:1 FA increased • JA decreased at 24 H • Implication: • JA may not regulate resistance • OPDA & SA may regulate resistant responses Response
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