Genes and mutants affecting virus infection in rapeseed – GAMAVIR

Viruses are among the parasites that induce the most severe damages on cultivated plants. Despite the
availability of insecticides to control insect vectors and of cultivars that show resistance to specific virus
strains, sustained protection of our crops against viruses can only be achieved if approaches are built on
a thorough understanding of the molecular mechanisms that determine virus:host compatibility and
disease. Viral infection is associated with the altered expression of host genes, many of which are
caused by fine-tuned interactions with the host RNA silencing machinery, likely to ultimately facilitate the
development of systemic infection. RNA silencing also acts to restrict virus overproduction. Thus, RNA
silencing is utilized by both the virus and its host to maintain a subtle equilibrium between virus
multiplication and host integrity. It is generally conceived that agricultural crops and plants in natural
communities may harbor pathogens, including viruses, as symptom-free carriers and that disease may
develop if plants are stressed in a warmer climate. Thus, while normal, coevolved interactions of viruses
with the host RNA silencing machinery are optimally balanced such that infection is achieved without
causing damage to the host, viruses may cause dangerous outbreaks and disease if this subtle
equilibrium between virus multiplication and host integrity is disturbed. Given that RNA silencing
responds to temperature, it is of utmost urgency that we begin to understand how changes in climate will
affect the regulation and control of viruses within their susceptible hosts.
The partners in this project have extensive expertise in the analysis of genome-wide approaches to
investigate RNA silencing pathways and especially virus-inducible, small RNA (sRNA)-directed
regulatory nodes. Here, with support by an SME, we transfer results/expertise and extent this research
to the analysis of virus infection in Rapeseed (Oilseed rape, “Canola”, Brassica napus L), the largest
source of vegetable oil in the world. Rapeseed is vulnerable by a number of widespread viruses that
require extensive use of toxic insecticides to control them. In this project, we will i) gain insight how
virus-inducible sRNA:target regulatory networks contribute to the establishment of virus infection, and/or
host defense, and disease in this crop; ii) determine the influences of temperature on the balanced
regulation of these networks and derive important information with regard to climate change; iii) identify
virus-induced Rapeseed genes, and virus- and Rapeseed-derived sRNAs with their respective
Rapeseed gene targets to test their role in virus infection in Rapeseed and thus evaluate their potential
for approaches to achieve Rapeseed crop protection; iv) disseminate the results to Rapeseed breeders
and other stakeholders involved in Rapeseed production and thus contribute to the development of
sustained Rapeseed production.