Showing papers by "Jorunn I. B. Bos published in 2021"
TL;DR: The data suggest that plant resistance to aphids in non-host and poor-host interactions with these aphid species likely resides in different plant cell layers, and future work will take into account specific cell layers where resistances are based to improve crop resistance.
Abstract: Aphids are phloem-feeding insects that cause economic losses to crops globally. Whilst aphid interactions with susceptible plants and partially resistant genotypes have been well characterized, the interactions between aphids and non-host species are not well understood. Unravelling these non-host interactions can identify the mechanisms which contribute to plant resistance. Using contrasting aphid-host plant systems, including the broad host range pest Myzus persicae (host: Arabidopsis; poor-host: barley) and the cereal pest Rhopalosiphum padi (host: barley; non-host: Arabidopsis), we conducted a range of physiological experiments and compared aphid settling and probing behaviour on a host plant vs either a non-host or poor-host. In choice experiments, we observed that around 10% of aphids selected a non-host or poor-host plant species after 24 h. Using the Electrical Penetration Graph technique, we showed that feeding and probing behaviours differ during non-host and poor-host interactions when compared with a host interaction. In the Arabidopsis non-host interaction with the cereal pest R. padi aphids were unable to reach and feed on the phloem, with resistance likely residing in the mesophyll cell layer. In the barley poor-host interaction with M. persicae, resistance is likely phloem-based as phloem ingestion was reduced compared with the host interaction. Overall, our data suggest that plant resistance to aphids in non-host and poor-host interactions with these aphid species likely resides in different plant cell layers. Future work will take into account specific cell layers where resistances are based to dissect the underlying mechanisms and gain a better understanding of how we may improve crop resistance to aphids.
14 citations
TL;DR: In this article, the authors used qualitative and quantitative synthesis techniques to determine whether drought stress has a negative, positive or null effect on aphid fitness and examined these effects in relation to (a) aphid biology, (b) geographical region, and (c) host plant biology.
Abstract: Aphids are abundant in natural and managed vegetation, supporting a diverse community of organisms and causing damage to agricultural crops. Due to a changing climate, periods of drought are anticipated to increase, and the potential consequences of this for aphid-plant interactions are unclear.Using a meta-analysis and synthesis approach, we aimed to advance understanding of how increased drought incidence will affect this ecologically and economically important insect group and to characterize any potential underlying mechanisms. We used qualitative and quantitative synthesis techniques to determine whether drought stress has a negative, positive, or null effect on aphid fitness and examined these effects in relation to (a) aphid biology, (b) geographical region, and (c) host plant biology.Across all studies, aphid fitness is typically reduced under drought. Subgroup analysis detected no difference in relation to aphid biology, geographical region, or the aphid-plant combination, indicating the negative effect of drought on aphids is potentially universal. Furthermore, drought stress had a negative impact on plant vigor and increased plant concentrations of defensive chemicals, suggesting the observed response of aphids is associated with reduced plant vigor and increased chemical defense in drought-stressed plants.We propose a conceptual model to predict drought effects on aphid fitness in relation to plant vigor and defense to stimulate further research.
12 citations
TL;DR: In this article, the role of plant defensive processes in mediating the interactions between the environment, plants, and herbivorous insects was highlighted, with the authors showing that the expression of thionin genes, plant defensive compounds that contribute to aphid resistance, increase ten-fold in susceptible plants exposed to drought stress but remain at constant levels in the partially resistant plant, suggesting they play an important role in modulating aphid populations.
Abstract: Crops are exposed to myriad abiotic and biotic stressors with negative consequences. Two stressors that are expected to increase under climate change are drought and infestation with herbivorous insects, including important aphid species. Expanding our understanding of the impact drought has on the plant-aphid relationship will become increasingly important under future climate scenarios. Here we use a previously characterised plant-aphid system comprising a susceptible variety of barley, a wild relative of barley with partial-aphid resistance, and the bird cherry-oat aphid to examine the drought-plant-aphid relationship. We show that drought has a negative effect on plant physiology and aphid fitness and provide evidence to suggest that plant resistance influences aphid responses to drought stress, with the expression of aphid detoxification genes increasing under drought when feeding on the susceptible plant but decreasing on the partially-resistant plant. Furthermore, we show that the expression of thionin genes, plant defensive compounds that contribute aphid resistance, increase ten-fold in susceptible plants exposed to drought stress but remain at constant levels in the partially-resistant plant, suggesting they play an important role in modulating aphid populations. This study highlights the role of plant defensive processes in mediating the interactions between the environment, plants, and herbivorous insects.