〓 Research Area : Molecular Virology

Study on viromes in crop phytobiomes
Phytobiomes refer to the complex networks between
plants and their associated communities of organisms
including bacteria, fungi, viruses and invertebrates.
Phytobiomes are becoming increasingly recognized asimportant factors in plant health and productivity, but inparticular, little is known about the diversities of virus
communities in agricultural cropping system. Taking
advances of the next generation sequencing and metagenomics, our group studies on viromes in fungi andinsects that are associated with crop plants. We aim tofind out whether these viral communities influence theirhosts and promote the health and growth of crop plants.

Study of non-retroviral RNA virus-like elements in thegenome of the plants, insects and fungi
The availability of genome sequences of a large number of eukaryotes has led to the discovery of endogenous non-retroviral RNA virus-like elements, also
known as endogenous viral elements (EVEs). Theseelements are considered as fossil of RNA virus integrated into host genomes by as-yet-unknown mechanisms. To gain deeper insight into the long-term viralevolution and host-virus coevolution, our research is
focused on identification and analysis of the EVEs in
the genome of the plants, insects and fungi.

〓 Assoc. Prof.
KONDO Hideki〓 Research Area : Molecular Virology

Plant-Virus interactions〓 Assoc. Prof.
HYODO Kiwamu

Plants are constantly attacked by various kinds of pathogens and pests, resulting in 40% yield
losses annually. Among plant pathogens that pose a major threat to sustainable agriculture andglobal food security, viruses account for nearly half of the plant endemics and cause estimatedeconomic losses more than US$30 billion annually. Positive-sense single-stranded (+ss)RNAviruses are the most abundant in plant viruses and cause the economically important diseases inmajor vegetable and field crops worldwide. The vast majority of plant (+)ssRNA viruses are very
simple entities comprising a nucleic acid genome encoding from 4 to 11 viral proteins needed
for genome replication, local and systemic spread within the host plant, and transmission to a
new host. Despite the simple nature of these pathogens, there is still much to be learned abouthow they interact with their hosts and cause disease. Understanding the molecular mechanisms
underlying pathogenicity of (+)ssRNA viruses is a crucial step towards the design of effective
strategies for crop protection.
In general, virally encoded proteins have a multifunctional property with the potential to interact
with several virus- and host-derived molecules, thus creating a complex web of molecular interactions in infected cells. Because of the limited number of viral-encoded proteins, (+)ssRNA
viruses need to subvert the host cell machinery for their own vital functions, ultimately creating acellular environment favorable to the infection. For this purpose, (+)ssRNA plant viruses co-opt
an array of host-derived factors (referred to as proviral host factors) to establish viral infection, in
which viruses remodel their functions to facilitate every step of the viral life cycle. The identification of the global landscape of plant-virus interactions at the molecular level is key to understandhow the virus hijacks the host cell to facilitate infection.
Our research aims at deciphering the molecular network of plant-virus interactions using (+)
ssRNA plant viruses as models. Discoveries in this area will provide insight into host-virus interactions as well as identify new breeding targets for the development of virus-resistant crops.

Graduate School of Environmental and Life Science, Okayama University55