1 insect-microorganism-plant interactions 2 nd discussion session 5 th lecture

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Insect-Microorganism-Plant Insect-Microorganism-Plant InteractionsInteractions

22ndnd Discussion session Discussion session

55thth Lecture Lecture

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Insect-Microorganism-Plant Insect-Microorganism-Plant InteractionsInteractions

FactFactInsects and microorganisms require hosts. Insects and microorganisms require hosts.

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IntroductionIntroduction

Insects + Micro Plants

Directly or indirectly interactions

MutualismMutualism

ParasitismParasitism

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Plant + Micro Insects

Directly or indirectly

MutualismMutualism

ParasitismParasitism

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Plant-Microbes-InsectsPlant-Microbes-Insects

When an insect touches a plant, it touches When an insect touches a plant, it touches Microbes (mainly bacteria) and their metabolic Microbes (mainly bacteria) and their metabolic products. products.

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What are the benefits for microbes being on What are the benefits for microbes being on plants.plants.

House that may provide shelter, suitable House that may provide shelter, suitable microclimate …etc for microbesmicroclimate …etc for microbes

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OutlinesOutlines

1- Endophytic Fungi1- Endophytic Fungi 2- 2- Insect orientation by Bacteria 3- Entomopathogens-insect-plant

interactions 4- Symbiotic bacteria in insects

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Endophytic FungiEndophytic Fungi

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The endophyte is actually a fungus that lives, The endophyte is actually a fungus that lives, grows and thrives inside a host plantgrows and thrives inside a host plant

Most terrestrial plants are colonized by one or Most terrestrial plants are colonized by one or several species of endophytic fungi which can several species of endophytic fungi which can be isolated from healthy-looking host tissuebe isolated from healthy-looking host tissue

Endophytes are contained within the plant Endophytes are contained within the plant without disease. Plant tissues remain entire without disease. Plant tissues remain entire and functional. and functional.

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The endophyte and the grass plant form a The endophyte and the grass plant form a mutually beneficial relationship; the plant mutually beneficial relationship; the plant feeds and "houses" the endophyte while the feeds and "houses" the endophyte while the endophyte helps the plant survive insects, heat endophyte helps the plant survive insects, heat and drought. and drought.

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Endophytes may upregulate host responses to Endophytes may upregulate host responses to pathogens and pestspathogens and pests. . Chaetomium globosumChaetomium globosum has been shown to increase host resistance to has been shown to increase host resistance to rust and tan spot pathogens in wheat. Direct rust and tan spot pathogens in wheat. Direct interactions appear to be too small to measure interactions appear to be too small to measure in this case. Presence of in this case. Presence of Lecanicillium lecaniiLecanicillium lecanii appears to reduce the feeding by aphids from appears to reduce the feeding by aphids from leaves of cotton leaves of cotton

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Plants may benefit from the presence of endophytes Plants may benefit from the presence of endophytes in many ways. Potential plant benefits have been in many ways. Potential plant benefits have been examined in only a few cases. examined in only a few cases. Rhabdocline parkeriRhabdocline parkeri produces a compound that reduces needle attack by produces a compound that reduces needle attack by borers. Metabolites produced by borers. Metabolites produced by PhomopsisPhomopsis sp in sp in cotton appear to deter larvae of cotton appear to deter larvae of HelicoverpaHelicoverpa from from feeding on leaves. The parallels with feeding on leaves. The parallels with NeotyphodiumNeotyphodium are clear. In addition, aphids feeding on leaves of are clear. In addition, aphids feeding on leaves of cotton may become colonized by cotton may become colonized by Lecanicillium Lecanicillium lecaniilecanii, when conditions permit. Thus the aphid may , when conditions permit. Thus the aphid may be killed or it may transfer the fungus to another leaf be killed or it may transfer the fungus to another leaf

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2Insect orientation by Bacteria

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Fruit flies-Bacteria-plant Fruit flies-Bacteria-plant interactionsinteractions

Bacteria as adult foodBacteria as adult food Associated with oviposition site, host fruit Associated with oviposition site, host fruit

surfaces, and larval infested tissuessurfaces, and larval infested tissues Bacteria orient fruit flies to the suitable hostBacteria orient fruit flies to the suitable host

Insect orientation by Bacteria

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3 Entomopathogens-insect-plant interactions

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Entomopathogens-insect-plant interactions

Plants can use entomopathogens as bodyguards Plants can use entomopathogens as bodyguards

1) maintaining a population of bodyguards on 1) maintaining a population of bodyguards on the plant surface,the plant surface,

(2) increasing contact rates between insect host (2) increasing contact rates between insect host and pathogen andand pathogen and

(3) increasing the susceptibility of the host. (3) increasing the susceptibility of the host.

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Plants produce many secondary compounds that

confer protection against herbivore feeding (Karban

and Baldwin 1997). In addition to their direct effects

on herbivores, these compounds may interact with

bacterial, fungal, and viral pathogens of herbivores.

Secondary plant metabolites have shown both synergistic and antagonistic effects on toxicity of B. thuringiensissubsp. kurstaki against the gypsy moth.

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For example, oak (Quercus spp.) tannins, and conifer terpenoidscan decrease toxicity of B. thuringiensis subsp.kurstaki against gypsy moths (Barbosa 1988, Appel andSchultz 1994, Farrar et al. 1996). In contrast, activityagainst larvae feeding on aspen (Populus spp.) increasedwith increasing foliar levels of phenolic glycosides(Hwang et al. 1995). Secondary metaboliteshave been hypothesized to be responsible for therelatively low activity of B. thuringiensis subsp.kurstaki against gypsy moth larvae on willow (Salixspp.) (Farrar et al. 1996).

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the fungal pathogen the fungal pathogen Beauveria bassianaBeauveria bassiana sprayed sprayed on to US corn was found to grow into the plant on to US corn was found to grow into the plant and provide season-long control of corn borer and provide season-long control of corn borer larvae ( larvae ( Bing & Lewis 1991Bing & Lewis 1991). ).

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Many plant traits will influence directly or indirectly the Many plant traits will influence directly or indirectly the survival of entomopathogens. Although certainly not survival of entomopathogens. Although certainly not the only selection pressure on these traits, selection may the only selection pressure on these traits, selection may mould them to improve pathogen persistence. Examples mould them to improve pathogen persistence. Examples are canopy architecture, leaf form and leaf colour, are canopy architecture, leaf form and leaf colour, which can greatly diminish the harmful effects of UV which can greatly diminish the harmful effects of UV on these pathogen propagules. Other examples include on these pathogen propagules. Other examples include the density of hairs, waxiness, the veins, size and shape the density of hairs, waxiness, the veins, size and shape of leaf, angle of the leaf to the stem, number of stomata of leaf, angle of the leaf to the stem, number of stomata and density of the canopy, which will influence the and density of the canopy, which will influence the microclimate of the leaf, the thickness of the boundary microclimate of the leaf, the thickness of the boundary layer and the effects of wind and rain layer and the effects of wind and rain

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Aschersonia aleyrodisAschersonia aleyrodis were found to retain were found to retain infectivity to whitefly much better on some infectivity to whitefly much better on some plants (e.g. cucumber) than others (e.g. plants (e.g. cucumber) than others (e.g. poinsettia). poinsettia).

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laboratory study by laboratory study by IgnoffoIgnoffo et al.et al. (1977 (1977 ), who ), who demonstrated that soybean seedlings can pick demonstrated that soybean seedlings can pick up spores of the fungus up spores of the fungus Nomuraea rileyiNomuraea rileyi from from the soil and that these spores can subsequently the soil and that these spores can subsequently infect larvae of infect larvae of Trichoplusia niTrichoplusia ni (soybean (soybean looper). looper).

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Brown Brown et alet al. (1995 . (1995 ). The authors found that the ). The authors found that the germination of conidia of the entomophthoralean germination of conidia of the entomophthoralean pathogen pathogen PandoraPandora ( = ( = EryniaErynia) ) neoaphidisneoaphidis was was inhibited by volatiles released by tobacco plants in inhibited by volatiles released by tobacco plants in response to herbivory by response to herbivory by Myzus nicotianaeMyzus nicotianae (tobacco (tobacco aphids). aphids).

Germination would in this instance lead to the Germination would in this instance lead to the production of secondary conidia, which would re-production of secondary conidia, which would re-disperse away from the leaf. Thus, the authors disperse away from the leaf. Thus, the authors hypothesized that the conidia "sit and wait" until they hypothesized that the conidia "sit and wait" until they are picked up, whereupon they germinate to infect the are picked up, whereupon they germinate to infect the aphid hosts. aphid hosts.

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Bacteria was sampled from fruit-free plants, Bacteria was sampled from fruit-free plants, plants without fruits (just were harvested) and plants without fruits (just were harvested) and plant with fruits.plant with fruits.

Fruit fly Bactrocera proved an olfactory to Fruit fly Bactrocera proved an olfactory to attract flies to the host plantsattract flies to the host plants

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Plant-mediated interactions between Plant-mediated interactions between pathogenicpathogenic microorganisms and herbivorous insectsmicroorganisms and herbivorous insects

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Plant-mediated interactions between Plant-mediated interactions between pathogenic microorganisms and herbivorous pathogenic microorganisms and herbivorous

insectsinsectsTypes:- Types:-

1.1. Direct plant-mediated effectDirect plant-mediated effect

2.2. Locally plant-mediated effectLocally plant-mediated effect

3.3. Systemic effect Systemic effect

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Direct plant-mediated effectDirect plant-mediated effect

Effect on antagonist 2 results from the physical Effect on antagonist 2 results from the physical presence or activity of antagonist 1 and/or from presence or activity of antagonist 1 and/or from plant responses induced by antagonist 1 plant responses induced by antagonist 1

Some of these interactions are direct, for Some of these interactions are direct, for example, when arthropods vectorexample, when arthropods vector

phytopathogenic microorganismsphytopathogenic microorganisms

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Locally plant-mediated effectLocally plant-mediated effect

Effect on antagonist 2 results exclusively from Effect on antagonist 2 results exclusively from plant response induced by antagonist 1. Both plant response induced by antagonist 1. Both antagonists are were present on the same antagonists are were present on the same morphological entity of the plant (typically leaf) morphological entity of the plant (typically leaf)

The term local refers to interactions in which The term local refers to interactions in which pathogens and arthropods used the same plant pathogens and arthropods used the same plant tissue at the same or different timestissue at the same or different times

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Systemic effectSystemic effect

Effect on antagonist 2 results exclusively from plant Effect on antagonist 2 results exclusively from plant response induced by antagonist 1. Each antagonist is or response induced by antagonist 1. Each antagonist is or was active on a different morphological entity of the was active on a different morphological entity of the plant.plant.

Indirect interactions between phytopathogenic Indirect interactions between phytopathogenic microorganisms and herbivorous arthropods can occur microorganisms and herbivorous arthropods can occur when infection or infestation by a first attacker alters the when infection or infestation by a first attacker alters the shared host plant in a way that affects a second attacker shared host plant in a way that affects a second attacker that is often spatially or temporally separated from the that is often spatially or temporally separated from the firstfirst

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Plant-mediated interactions between pathogenic Plant-mediated interactions between pathogenic microorganisms and herbivorous insectsmicroorganisms and herbivorous insects

ObjectivesObjectives

plant-mediated interactions will facilitate an plant-mediated interactions will facilitate an understanding of how plants coordinateunderstanding of how plants coordinate

and integrate their defenses against multiple and integrate their defenses against multiple biotic threats.biotic threats.

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The contemporary view of plant defense recognizes that The contemporary view of plant defense recognizes that plants contend simultaneously with myriad attackers by plants contend simultaneously with myriad attackers by utilizing a multifaceted array of resistance mechanisms, utilizing a multifaceted array of resistance mechanisms, involving not only primary and secondary metabolites involving not only primary and secondary metabolites and morphological and physicochemical traits, but also and morphological and physicochemical traits, but also mechanisms that allow plants to tolerate attack and mechanisms that allow plants to tolerate attack and recruit the natural enemies of attackersrecruit the natural enemies of attackersRecruit = to raise or strengthen Recruit = to raise or strengthen

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FEEDING BY ARTHROPODS ON FEEDING BY ARTHROPODS ON DISEASED PLANT TISSUESDISEASED PLANT TISSUES

Interactions in which virus infection has a beneficial Interactions in which virus infection has a beneficial effect on vectoring homopteranseffect on vectoring homopteransare thought to reflect a mutualistic relationship between are thought to reflect a mutualistic relationship between virus and vector.virus and vector.DataData consistent with this hypothesis were presented, for consistent with this hypothesis were presented, for example, in a studyexample, in a studyin which rates of increase of in which rates of increase of Myzus persicae Myzus persicae on virus-on virus-infected potatoes were positivelyinfected potatoes were positivelycorrelated with the level of dependence of the virus on correlated with the level of dependence of the virus on the aphid for dispersalthe aphid for dispersal

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Similarly, recent studies demonstrated that aphid Similarly, recent studies demonstrated that aphid vectors such as vectors such as RhopalosiphumRhopalosiphum

padi padi and and Sitobion avenae Sitobion avenae had greater preference had greater preference for, and higher fecunditiesfor, and higher fecundities

and rates of increase on, cereals infected with and rates of increase on, cereals infected with Barley yellow dwarf virus Barley yellow dwarf virus than forthan for

healthy cereals under laboratory conditionshealthy cereals under laboratory conditions

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Even in interactions in which virus infection has no net effect or Even in interactions in which virus infection has no net effect or a net negative effect on vector population growth or fitness, a net negative effect on vector population growth or fitness, changes in vector settling or feeding behavior may be adaptations changes in vector settling or feeding behavior may be adaptations to increase the spread of the virusto increase the spread of the virusFor example, the leafhopper For example, the leafhopper Nepotettix virescensNepotettix virescens, a vector of , a vector of Tungro virus Tungro virus in rice, grew slower, fed less, was less fecund, and in rice, grew slower, fed less, was less fecund, and experienced higher mortality on infected rice plants than on experienced higher mortality on infected rice plants than on uninfected plants. Despite this overall negative effect of infection uninfected plants. Despite this overall negative effect of infection on leafhoppers, initial settling on on leafhoppers, initial settling on TungroTungro-infected rice plants was -infected rice plants was higher. The alterations in initial settling behavior and feeding higher. The alterations in initial settling behavior and feeding behavior were hypothesized to increase spread of the virus.behavior were hypothesized to increase spread of the virus.

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Two studies have shown positive effects of systemic Two studies have shown positive effects of systemic virus infection on nonhomopteran arthropods. Survival virus infection on nonhomopteran arthropods. Survival of Colorado potato beetle larvae was higher onof Colorado potato beetle larvae was higher ontomato plants infected with tomato plants infected with Tobacco mosaic virus Tobacco mosaic virus (TMV) than on healthy plants(TMV) than on healthy plantsLarvae of the Mexican bean beetle fed less and grew Larvae of the Mexican bean beetle fed less and grew slower on uninfected bean plants than on bean plants slower on uninfected bean plants than on bean plants infected with infected with Southern bean mosaic virus Southern bean mosaic virus or or Bean pod Bean pod mottle virus mottle virus (88). In the latter case, the insect vectors (88). In the latter case, the insect vectors the viruses.the viruses.

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The effects on arthropods of feeding on tissues The effects on arthropods of feeding on tissues infected with pathogenic fungiinfected with pathogenic fungi

or bacteria can be positive or negative.or bacteria can be positive or negative.

European corn borer larvae developed European corn borer larvae developed approximately 20% faster on maizeapproximately 20% faster on maize

showing symptoms of stalk rot caused by showing symptoms of stalk rot caused by Colletotrichum graminicola Colletotrichum graminicola than on nondiseased than on nondiseased tissuetissue

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In contrast, systemic infection of In contrast, systemic infection of CirsiumCirsium

arvense arvense with the necrotrophic fungus with the necrotrophic fungus Phoma Phoma destructiva destructiva resulted in a number ofresulted in a number of

negative effects on the beetle negative effects on the beetle Cassida Cassida rubiginosarubiginosa, including reduced oviposition,, including reduced oviposition,

feeding, survival, rates of growth, and pupal feeding, survival, rates of growth, and pupal weightsweights

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One factor that appears to influence the outcome One factor that appears to influence the outcome of these types of tripartite interactions is the of these types of tripartite interactions is the constitutive quality of the infected plant for the constitutive quality of the infected plant for the herbivore. The negative effects of rust infection herbivore. The negative effects of rust infection on larvae of on larvae of Tyria jacobaeae Tyria jacobaeae were greater whenwere greater whenlarvae fed on infected leaves of larvae fed on infected leaves of Tussilago Tussilago farfarafarfara, a poor host for this insect species, than , a poor host for this insect species, than when larvae fed on rust-infected when larvae fed on rust-infected Senecio Senecio jacobaeajacobaea, a superior host, a superior host

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Similarly, the increase in relative growth rates Similarly, the increase in relative growth rates and fecundities of black bean aphids (and fecundities of black bean aphids (Aphis Aphis fabaefabae) on bean leaves infected with the ) on bean leaves infected with the necrotroph necrotroph Botrytis fabae Botrytis fabae was greater on a was greater on a resistant bean variety than on a susceptible oneresistant bean variety than on a susceptible one

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PLANT-MEDIATED EFFECTS OF PLANT-MEDIATED EFFECTS OF PATHOGEN INFECTION ON INSECTSPATHOGEN INFECTION ON INSECTS

Several other studies have investigated the Several other studies have investigated the systemic effects of localized infectionsystemic effects of localized infection

by bacterial and fungal pathogens on subsequent by bacterial and fungal pathogens on subsequent attackers. Again, bothattackers. Again, both

positive and negative effects have been positive and negative effects have been demonstrateddemonstrated

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Localized infection of one leaflet on young tomato Localized infection of one leaflet on young tomato plants with plants with P. syringae P. syringae pv. pv. tomato tomato resulted in 50% to resulted in 50% to 80% reductions in growth rates of the noctuid 80% reductions in growth rates of the noctuid Helicoverpa zea Helicoverpa zea on the remaining leaflets of the on the remaining leaflets of the inoculated leaf. In contrast, infection of terminal leaflets inoculated leaf. In contrast, infection of terminal leaflets by the hemibiotrophic oomycete by the hemibiotrophic oomycete Phytophthora infestans Phytophthora infestans had no effect on leaf-systemic resistance to had no effect on leaf-systemic resistance to H. zeaH. zea, , demonstrating again that infection by different demonstrating again that infection by different pathogens canpathogens can

have different results for the same herbivorehave different results for the same herbivore

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Infection of stems of peanuts withInfection of stems of peanuts with

the necrotrophic white mold fungus, the necrotrophic white mold fungus, Sclerotium Sclerotium rolfsiirolfsii, altered the resistance of, altered the resistance of

leaves to a leaf-feeding caterpillar, leaves to a leaf-feeding caterpillar, Spodoptera Spodoptera exiguaexigua. Survival was 20% higher, development ∼. Survival was 20% higher, development ∼was faster, pupae were 25% heavier, and ∼was faster, pupae were 25% heavier, and ∼feeding was greater onfeeding was greater on

diseased plantsdiseased plants

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Only a few studies have directly compared the systemic Only a few studies have directly compared the systemic effects of pathogeneffects of pathogeninfection on arthropods with local effects. Local effects infection on arthropods with local effects. Local effects were usually strongerwere usually strongerthan systemic effectsthan systemic effectsLocal effects were usually stronger than systemic Local effects were usually stronger than systemic effects. Weights of larvae and pupae were reduced and effects. Weights of larvae and pupae were reduced and development times were extended for the beetle development times were extended for the beetle Phaedon cochleariae Phaedon cochleariae feeding on cabbage leaves feeding on cabbage leaves infected with the necrotroph infected with the necrotroph Alternaria brassicaeAlternaria brassicae, but , but the effects were not systemicthe effects were not systemic

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Local effects were usually strongerLocal effects were usually stronger

than systemic effects.Weights of larvae and than systemic effects.Weights of larvae and pupae were reduced and developmentpupae were reduced and development

times were extended for the beetle times were extended for the beetle Phaedon Phaedon cochleariae cochleariae feeding on cabbage leavesfeeding on cabbage leaves

infected with the necrotroph infected with the necrotroph Alternaria Alternaria brassicaebrassicae, but the effects were not systemic, but the effects were not systemic

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In addition, melon aphid (In addition, melon aphid (Aphis gossypiiAphis gossypii) ) produced fewer offspring on diseased leaves produced fewer offspring on diseased leaves when leaves were almost completely necrotic, when leaves were almost completely necrotic, but produced more offspring on diseased leaves but produced more offspring on diseased leaves when symptoms were not as severe. No systemic when symptoms were not as severe. No systemic effects on aphid reproduction were observed. In effects on aphid reproduction were observed. In addition to showing the importance of spatial addition to showing the importance of spatial scale, this latter study also shows the importance scale, this latter study also shows the importance of disease severity in determining effects on of disease severity in determining effects on herbivores.herbivores.

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PLANT-MEDIATED EFFECTS OF PLANT-MEDIATED EFFECTS OF ARTHROPODS ON PATHOGENSARTHROPODS ON PATHOGENS

Several recent studies have documented Several recent studies have documented increases in resistance to pathogens following increases in resistance to pathogens following feeding by arthropods with a sucking mode of feeding by arthropods with a sucking mode of feeding. Because sucking insects can induce feeding. Because sucking insects can induce biochemical responses similar to those induced biochemical responses similar to those induced by pathogensby pathogens

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PLANT-MEDIATED EFFECTS OF PLANT-MEDIATED EFFECTS OF ARTHROPODS ON PATHOGENSARTHROPODS ON PATHOGENS

Infesting rice plants with the white-backedInfesting rice plants with the white-backed

planthopper, planthopper, Sogatella furciferaSogatella furcifera, dramatically , dramatically increased the resistance of plantsincreased the resistance of plants

to rice blast, to rice blast, Magnaporthe griseaMagnaporthe grisea

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In tomato, plants previously infestedIn tomato, plants previously infested

with silverleaf whitefly, with silverleaf whitefly, Bemisia argentifoliiBemisia argentifolii, , were more resistant to powdery mildew were more resistant to powdery mildew ((Erysiphe cichoracearumErysiphe cichoracearum), but not to TMV, than ), but not to TMV, than were control plantswere control plants

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Feeding by chewing insects can also influence Feeding by chewing insects can also influence plant resistance to pathogens.plant resistance to pathogens.

Feeding by Feeding by H. zea H. zea on the terminal leaflets of on the terminal leaflets of tomato leaves resulted in a 30% reductiontomato leaves resulted in a 30% reduction

in lesion numbers caused by in lesion numbers caused by P. syringae P. syringae on on undamaged leaflets of damagedundamaged leaflets of damaged

leavesleaves

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Several investigations of tripartite interactions Several investigations of tripartite interactions among pests of alfalfa have alsoamong pests of alfalfa have also

been conducted and again show the importance been conducted and again show the importance of feeding type. Defoliation ofof feeding type. Defoliation of

alfalfa by yellowstriped armyworms did not alfalfa by yellowstriped armyworms did not affect severity of crown rot caused byaffect severity of crown rot caused by

F. oxysporumF. oxysporum

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Hatcher et al. (51) documented a plant-systemic Hatcher et al. (51) documented a plant-systemic increase in the resistance ofincrease in the resistance of

Rumex Rumex sp. to the rust fungus sp. to the rust fungus Uromyces rumicis Uromyces rumicis following feeding by following feeding by G. viridulaG. viridula

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MECHANISMS OF PLANT-MECHANISMS OF PLANT-MEDIATED INTERACTIONSMEDIATED INTERACTIONS

Activation of Plant Response PathwaysActivation of Plant Response PathwaysDEFENSE SIGNALING IN PLANTSDEFENSE SIGNALING IN PLANTSSECONDARY METABOLITESSECONDARY METABOLITESCROSS-EFFECTSCROSS-EFFECTSCROSS-TALKCROSS-TALK

Other Mechanisms of Plant-Mediated InteractionsOther Mechanisms of Plant-Mediated InteractionsCHANGES IN PRIMARY METABOLISMCHANGES IN PRIMARY METABOLISMPLANT STRESS-MEDIATED INTERACTIONSPLANT STRESS-MEDIATED INTERACTIONSCHANGES IN PLANT GROWTH AND MORPHOLOGYCHANGES IN PLANT GROWTH AND MORPHOLOGYINTERACTIONS MEDIATED BY NATURAL ENEMIESINTERACTIONS MEDIATED BY NATURAL ENEMIES

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Symbiotic bacteria in insects

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symbiotic micro-organisms that provide the symbiotic micro-organisms that provide the insect with nutrients or detoxify plant insect with nutrients or detoxify plant allelochemicals allelochemicals

They may expand the plant range of insects by They may expand the plant range of insects by improving insect utilization of otherwise improving insect utilization of otherwise marginal plants marginal plants

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What bacteria do for the Insects.What bacteria do for the Insects.A- Degradation of plant food A- Degradation of plant food

B- Synthesis of nutritional requisites that plants do B- Synthesis of nutritional requisites that plants do not provide at all or provide in insufficient not provide at all or provide in insufficient quantities (sterols, amino acids…. quantities (sterols, amino acids….

C- Detoxification of plant allelochemicalsC- Detoxification of plant allelochemicals

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A comprehensive understanding of the

biology of insects requires that they be

studied in ecological context with

microorganisms as an important component

of the system

E.A. Steinhaus (1960)

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1 insect-microorganism-plant interactions 2 nd discussion session 5 th lecture

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