Forschungs- & Entwicklungsinformationsdienst der Gemeinschaft - CORDIS


APHIDHOST Berichtzusammenfassung

Project ID: 310190
Gefördert unter: FP7-IDEAS-ERC
Land: United Kingdom

Mid-Term Report Summary - APHIDHOST (Molecular determinants of aphid host range)

Aphids are phloem-feeding insects that cause feeding damage and transmit economically important plant viruses to many crops worldwide. Many aphid species are restricted to one or few host plants, while some aphids, many of which are of agricultural importance, can infest a wide range of plant species. An important observation is that aphids spend a considerable time on nonhost species, where they probe the leaf tissue and secrete saliva, but for unknown reasons are unable to ingest phloem sap. These findings suggest that aphids, like plant pathogens, interact with nonhost plants at the molecular level, but potentially are no successful in suppressing plant defenses and/or releasing nutrients. Recent evidence supports a model wherein aphids secreted salivary proteins inside host plants, which interact with host proteins to reprogram host cell processes and promote infestation. The overall aim of the proposed project is to gain insight into the level of cellular host reprogramming that takes place during aphid-host interactions, the cellular processes involved in aphid nonhost resistance, and the role of aphid effectors in determining host range. For this purpose we will compare interactions of three economically important aphid species, Myzus persicae (green peach aphid), Myzus cerasi and Rhopalosiphum padi (bird cherry oat aphid), with host and nonhost plants.
Progress highlights to date are summarized below:
We have assessed transcriptional responses in different plant species upon host, poor-host and non-host interaction with different aphid species. This not only provided very novel insights into the plant genes affected by the different types of aphid interactions, but also allowed us to identify novel plant genes involved in host susceptibility and nonhost resistance. Moreover, we found that plant responses to aphids differ across plant species, with some species responding very similar to interactions and others responding quite differently.
Also, our work has implicated novel sets of aphid secreted salivary proteins in plant-aphid interactions. We identified and compared aphid effector repertoires from three aphid species and found sets of highly conserved effectors as well as those potentially unique to certain aphid species and/or under diversifying selection. We also detected effector variation within genotypes of M. persicae, an important broad host range pest. Further characterization of these effector repertoires to determine their role in host range is currently in progress.
One of the hypotheses underlying our research is that aphids secrete effector proteins inside their hosts, which target host proteins to promote infestation. We predict that these effectors only function in host but not nonhost plants and thus only interact with their targets in a suitable host. We have generated results supporting this hypothesis, in that some aphid effector-host protein interactions are specific to certain plant-aphid species interactions. This is an important finding and provides support for our model wherein aphid effectors contribute to host range.

Reported by

United Kingdom
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