Aphids may harbor a wide variety of facultative bacterial endosymbionts. These symbionts are transmitted maternally with high fidelity and they show horizontal trans-mission as well, albeit at rates too low to enable ...Aphids may harbor a wide variety of facultative bacterial endosymbionts. These symbionts are transmitted maternally with high fidelity and they show horizontal trans-mission as well, albeit at rates too low to enable infectious spread. Such symbionts need to provide a net fitness benefit to their hosts to persist and spread. Several symbionts haveachieved this by evolving the ability to protect their hosts against parasitoids. Reviewing empirical work and some models, I explore the evolutionary ecology of symbiont-conferredresistance to parasitoids in order to understand how defensive symbiont frequencies are maintained at the intermediate levels observed in aphid populations. I further show thatdefensive symbionts alter the reciprocal selection between aphids and parasitoids by augmenting the heritable variation for resistance, by increasing the genetic specificity of thehost-parasitoid interaction, and by inducing environment-dependent trade-offs. These effects are conducive to very dynamic, symbiont-mediated coevolution that is driven by frequency-dependent selection. Finally I argue that defensive symbionts represent a problem for biological control of pest aphids, and I propose to mitigate this problem byexploiting the parasitoids＇ demonstrated ability to rapidly evolve counteradaptations to symbiont-conferred resistance.展开更多
The synthesized Bacillus thuringiensis insecticidal protein gene crylA(b&c) and the synthesized gene GNA, (the mannose specific lectin from snowdrop ( Galanthus nivalis)), tumefaciens have been inserted into plant...The synthesized Bacillus thuringiensis insecticidal protein gene crylA(b&c) and the synthesized gene GNA, (the mannose specific lectin from snowdrop ( Galanthus nivalis)), tumefaciens have been inserted into plant expression vector pGW4BAI. Leave stripes of Nico-tiana tabacum var. K326 have been transformed with Agrobacterium tumefaciens strain LBA4404 harboring the plant expression vector. 28 kanamycin resistant tobacco plants展开更多
Four soybean [Glycine max （L.） Merr.] cultivars with soybean aphid resistance （Aphis glycines Matsmura）, p189, P203, P574, and P746, were identified in field test, choice test, and non-choice test, The grade of re...Four soybean [Glycine max （L.） Merr.] cultivars with soybean aphid resistance （Aphis glycines Matsmura）, p189, P203, P574, and P746, were identified in field test, choice test, and non-choice test, The grade of resistance to aphids and the damage index of P189, P203, and P746 were significantly different from the susceptible cultivars （P=0.05）. P574 and P746 showed antibiosis resistance, preventing aphids from reproducing on the plants. P203 showed antixenosis resistance, preventing aphids from reproducing in field test and choice test, but susceptible in non-choice test. Population development on plants was significantly different in field test, choice test, and non-choice test, which was caused by different selective pressures.展开更多
Hemipteran and dipteran insects have behavioral,cellular and chemical strategies for evading or coping with the host plant defenses making these insects particularly destructive pests worldwide. A critical component o...Hemipteran and dipteran insects have behavioral,cellular and chemical strategies for evading or coping with the host plant defenses making these insects particularly destructive pests worldwide. A critical component of a host plant＇s defense to herbivory is innate immunity. Here we review the status of our understanding of the receptors that contribute to perception of hemipteran and dipteran pests and highlight the gaps in our knowledge in these early events in immune signaling. We also highlight recent advances in identification of the effectors that activate pattern-triggered immunity and those involved in effector-triggered immunity.展开更多
文摘Aphids may harbor a wide variety of facultative bacterial endosymbionts. These symbionts are transmitted maternally with high fidelity and they show horizontal trans-mission as well, albeit at rates too low to enable infectious spread. Such symbionts need to provide a net fitness benefit to their hosts to persist and spread. Several symbionts haveachieved this by evolving the ability to protect their hosts against parasitoids. Reviewing empirical work and some models, I explore the evolutionary ecology of symbiont-conferredresistance to parasitoids in order to understand how defensive symbiont frequencies are maintained at the intermediate levels observed in aphid populations. I further show thatdefensive symbionts alter the reciprocal selection between aphids and parasitoids by augmenting the heritable variation for resistance, by increasing the genetic specificity of thehost-parasitoid interaction, and by inducing environment-dependent trade-offs. These effects are conducive to very dynamic, symbiont-mediated coevolution that is driven by frequency-dependent selection. Finally I argue that defensive symbionts represent a problem for biological control of pest aphids, and I propose to mitigate this problem byexploiting the parasitoids＇ demonstrated ability to rapidly evolve counteradaptations to symbiont-conferred resistance.
文摘The synthesized Bacillus thuringiensis insecticidal protein gene crylA(b&c) and the synthesized gene GNA, (the mannose specific lectin from snowdrop ( Galanthus nivalis)), tumefaciens have been inserted into plant expression vector pGW4BAI. Leave stripes of Nico-tiana tabacum var. K326 have been transformed with Agrobacterium tumefaciens strain LBA4404 harboring the plant expression vector. 28 kanamycin resistant tobacco plants
基金supported by the National Natural Science Foundation of China(30871549)the Key Basic Research of Shanghai Committee of Science and Technology,China(08JC1410500)
文摘Four soybean [Glycine max （L.） Merr.] cultivars with soybean aphid resistance （Aphis glycines Matsmura）, p189, P203, P574, and P746, were identified in field test, choice test, and non-choice test, The grade of resistance to aphids and the damage index of P189, P203, and P746 were significantly different from the susceptible cultivars （P=0.05）. P574 and P746 showed antibiosis resistance, preventing aphids from reproducing on the plants. P203 showed antixenosis resistance, preventing aphids from reproducing in field test and choice test, but susceptible in non-choice test. Population development on plants was significantly different in field test, choice test, and non-choice test, which was caused by different selective pressures.
基金supported by National Institute of Food and Agriculture(Award No.2010-65106-20675)supported by the National Science Foundation(Award No.IOS-072093 and IOSEAGER-1450331)Bill&Melinda Gates Foundation via a subcontract(B0426×5)from the National Research Institute,University of Greenwich,UK
文摘Hemipteran and dipteran insects have behavioral,cellular and chemical strategies for evading or coping with the host plant defenses making these insects particularly destructive pests worldwide. A critical component of a host plant＇s defense to herbivory is innate immunity. Here we review the status of our understanding of the receptors that contribute to perception of hemipteran and dipteran pests and highlight the gaps in our knowledge in these early events in immune signaling. We also highlight recent advances in identification of the effectors that activate pattern-triggered immunity and those involved in effector-triggered immunity.
