Plant Defenses - How Trees Defend Themselves And Why It .
Plant Defenses - How Trees DefendThemselves and Why it MattersPierluigi (Enrico) BonelloDept. of Plant Pathology
Why are we interested in this subject?è Plant defenses are the foundation of host plant resistanceè Resistance is a cost-effective and ecologically-sound approach todisease and insect managementè Resistance is compatible with other IPM techniques andsometimes it is singularly sufficient to suppress pest damage totolerable levelsèIn IPM, defense traits associated with resistance can be used as biomarkersfor selection of resistant plant germplasm2
Disease TriangleHostPathogenAmountofDiseaseEnvironment3
Why are we interested in this subject?è To apply resistance as an IPM tool we need to understand itè Only once we understand it will we be able to harness it to ouradvantage, i.e.èlower costs of pest controlèlower human and environmental impacts of pesticide use4
Layout of today’s talkè Major concepts in tree defense against pathogensè Current research on tree disease resistance5
Mechanisms of Pest ResistancePlants do not have an immune system as we understand it inhumans, they defend themselves using:è Mechanical (physical) barriers: preformed (passive), inducedè Chemical barriers : preformed (passive), inducedBut: mechanical barriers are always the result of chemicalprocesses!6
Preformed Mechanical Barriersè Leaves: e.g. cuticles, leaf hairs (trichomes)è Stem and roots: outer bark7
LEAVES(Manion, P.D. (1991) Tree Disease Concepts. Prentice Hall, Inc., Englewood Cliffs, N.J.)8
LEAVESYoung poplar leaf(susceptible toMarssonina leaf spot)Older poplar leaf(resistant toMarssonina leaf spot)9(Blanchette, R.A. & Biggs, A.R. (Eds.) (1992) Defense Mechanisms of Woody Plant Against Fungi. Springer-Verlag, Berlin)
STEMS(Rost et al. (1984) Botany - A Brief Introduction to Plant Biology. John Wiley & Sons, New York)10
Franceschi VR, Krokene P, Christiansen E, Krekling T (2005) Anatomical and chemical defenses of conifer bark against bark beetlesand other pests. New Phytologist 167 (2):353-375
STEMS12(Manion, P.D. (1991) Tree Disease Concepts. Prentice Hall, Inc., Englewood Cliffs, N.J.)
Preformed Chemical Barriersè Leaves:èexuded antibiotic chemicals, e.g. gallic acid from Norway maple leavesèantibiotics inside leaves (a plethora), e.g. resin in pine needles.è Stem and roots:èphloem and xylem usually contain all sorts of nasty chemicals13
Soluble chemicalsFranceschi VR, Krokene P, Christiansen E, Krekling T (2005) Anatomical andchemical defenses of conifer bark against bark beetles and other pests. NewPhytologist 167 (2):353-37514
Hickory cultivar susceptibleto Cladosporium caryigenumHickory cultivar resistantto Cladosporium caryigenum(Blanchette, R.A. & Biggs, A.R. (Eds.) (1992) Defense Mechanisms of Woody PlantAgainst Fungi. Springer-Verlag, Berlin)15
Induced Mechanical Barriers(Wound Healing)è Leaves: e.g. abscission zones, corky layersè Stem and roots: corky layers, new periderms16
LEAVESAlternaria leaf blightof ZinniaPhyllosticta leaf spot ofred maple17
STEMS18(Blanchette, R.A. & Biggs, A.R. (Eds.) (1992) Defense Mechanisms of Woody Plant Against Fungi. Springer-Verlag, Berlin)
STEMS19(Blanchette, R.A. & Biggs, A.R. (Eds.) (1992) Defense Mechanisms of Woody Plant Against Fungi. Springer-Verlag, Berlin)
STEMS(Blanchette, R.A. & Biggs, A.R. (Eds.) (1992) Defense Mechanisms of WoodyPlant Against Fungi. Springer-Verlag, Berlin)(Pearce, R.B. (1996) Tansley Review No. 87. Antimicrobial defences in thewood of living trees. New Phytologist 132, 203-233)20
Induced Chemical Barriersè All tissues: increased amounts of preformed antibiotic chemicals,new antibiotic chemicals, chemical changes of the cell walls, etc.è One of the main induced defense responses is increasedlignification21
Soluble chemicalsCell wall-bound chemicals, e.g. lignin22
Chemical Plant Defense Components of defense Constitutive (phytoanticipins) and induced (phytoalexins) Against herbivory (e.g. insects) Typically relies on constitutive phenolics Against infection (e.g. fungal pathogens) Typically relies on induced phenolicsIntensity and, more importantly, speed of accumulation often correlated toresistance23
PhenolicsSpecialized (secondary) metabolites Low molecular weightDerivatives of phenolChemical properties Organic compounds with structural heterogeneityBenzene ring with one or more hydroxyl groupAbsorb strongly in UV and / or visible lightHydroxyl group allows for different reactions24
“Raison d’être” of phenolicsSynthesis selected for throughout evolution Plant defenseProtection from environmental exposure, e.g. UV radiationPhysical supportInsect/animal attractantsSignalingAllelopathy25
Case Study: Sudden Oak Death26
New Approaches to Assess Coast Live Oak Resistance Before Infectionby the Invasive Pathogen Phytophthora ramorum Collaborators Anna Conrad, Luis Rodriguez-Saona, Stephen Opiyo – Ohio State Brice McPherson David Wood – University of California, Berkeley Sylvia Mori – Forest Service Statistical guidance Larry Madden – Ohio StateAnna O. Conrad27
Sudden Oak Death First documented in Marin County, CA in the mid-90’s. Associated with die-off of tanoak and coast live oak (CLO). Attacks by ambrosia and bark beetles and presence of fungi (e.g.Annulohypoxylon thouarsianum and Trametes versicolor) wereassociated with dying trees. Phytophthora ramorum identified as the causal agent in 2002.28
Pathogen: Phytophthora ramorum30
COAST LIVE OAK SUSCEPTIBILITY VARIESResistantSusceptible31
CANKER LENGTH PREDICTS RESISTANCE32
CANKER LENGTH PREDICTS SURVIVALExternal canker length measured 9 months following inoculation can be used topredict coast live oak survival 7 years following inoculation (McPherson et al., 2014).33
PHYTOCHEMICALS AND DEFENSE Ellagic acid and a tyrosol derivative are associated withresistant CLO (Nagle et al., 2011) Concentrations of 4 putative phenolic biomarkers ofresistance were identified from asymptomatic tissue ofalready infected CLO (McPherson et al., 2014) Ellagic acid and crude methanol extract from CLOphloem tissue both inhibit the growth of P. ramorum invitro (McPherson et al., 2014)34
PHENOLIC BIOMARKERS IDENTIFYRESISTANT CLO BEFORE INFECTION35
ELLAGIC ACID HAS STRONG ANTIPHYTOPHTHORA RAMORUM EFFECTS IN VITRO36
CONCLUSIONS Phytochemical biomarkers can predict CLO resistanceand, more importantly, survivalFirst example of biomarkers of resistance developed fornaturally regenerated trees growing under fieldconditions37
Why are we interested in this subject?è To apply resistance as an IPM tool we need to understand itè Only once we understand it will we be able to harness it to ouradvantage, i.e. lower costs of pest control lower human and environmental impacts of pesticide use38
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CONCLUSIONS Studying plant chemistry associated with resistance caninform managementSuch methods can be used on many other systems We are in the process of applying these approaches to Austrianpine resistance to Diplodia tip blight, as well as other keydiseases like white pine blister rust in whitebark pine, and ashdieback in Europe42
If interested in donatingto my program pleasego to my webpageplantpath.osu.edu/bonello43
è Plant defenses are the foundation of host plant resistance è Resistance is a cost-effective and ecologically -sound approach to disease and insect management è Resistance is compatible with other IPM techniques and sometimes it is singularly sufficient to suppress pest damage to tolerable levels è In IPM, defense traits associated with resistance can be used as biomarkers
The Man Who Planted Trees Curriculum Guide ABOUT TREES, pg. 1 ABOUT TREES, cont. pg. 12 Author Jean Giono once said that he wrote The Man Who Planted Trees because he wanted to “to make people love trees, or more precisely to make people love planting trees.” Read on to learn more about trees and the many
zero-delay lightweight defenses, we decided to avoid confu-sion and regularization defenses. Among our new defenses, FRONT is an obfuscation defense, while GLUE is in its own category as it forces the WF attacker to solve a different, much more difficult problem.
Trees Removed - Rural 60 50 70 50 75 125 100* Trees Planted 323 242 375** 245 162 80 200* *Forecast ** The 2019 "Trees Planted" amount reflects 225 City trees, plus 150 Ballpark Commons trees *** With more developments, we will need to plant more development trees and replacement trees
deletion operations, importance of balancing, AVL trees, searching insertion and deletions in AVL trees, redblack trees, comparison - with AVL trees, search insert and delete operations. 4 7. Multiway Trees: Issues in large dictionaries, m-way search trees, B-trees, search insert and delete operations, height of B-tree
Compare and contrast the Net and Applet Java packages 4. To develop Java application using Servlet . Trees - Binary trees - Binary tree representation and traversals - Threaded binary trees - Expression Trees -Binary Search Tree - Applications of trees. Balanced trees: AVL trees. Priority queue - Binary heap - Heap operations - Applications .
KEY TO THE TREES AND SHRUBS OF KANANASKIS COUNTRY 1A. Plant is a TREE with one main stem: Go to 2A & 2B 1B. Plant is a SHRUB with more than one main stem: Go to PAGE 8 SHRUBS 2A. Tree with leaves: Go to 3A & 3B TREES WITH LEAVES 2B. Tree with needles: Go to PAGE 4 EVERGREEN TREES TREES WITH LEAVES 3A. Leaves have a round leaf stem. If you place .
Balanced search tree: A search-tree data structure for which a height of O(lg n) is guaranteed when implementing a dynamic set of n items. Examples: AVL trees 2-3 trees B-trees Red-black trees Treaps and Randomized Binary Search Trees
the methods described in ASTM-C181 [4] and ISO 1927-3 [5]. From these results, the WI (based on the four first rams, calculated in Eq. (1) ), the extended WI (based on all 100 rams, calcu- lated in Eq. (2)) and changes in height and changes in density per ram as reported by the auto- mated sand-rammer. The density calculation is based on the .
