Plant Virus Biodiversity and Ecology

2 Pages·2006·0.29 MB·English

by  Wren, Jonathan D, Roossinck, Marilyn J, Nelson, Richard S, Scheets, Kay, Palmer, Michael W, Melcher, Ulrich

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Plant Virus Biodiversity and Ecology
Jonathan D. Wren, Marilyn J. Roossinck, Richard S. Nelson, Kay Scheets, Michael W. Palmer, Ulrich Melcher*
The International Committee Identification Data
for the Taxonomy of Viruses Exchange database [4].
IM* ac4Md from • piif«
recognized a global total of Most of the available
about 2,000 species of viruses as of virus information we
2005 [1]. However, data on viruses have is derived from v««a
that infect terrestrial organisms, cultivated crop species, M
including plants, are sparse, and recent yet these species only
sequencing of samples from marine comprise a minute
environments for viruses suggests fraction of all plant
that 2,000 is a gross underestimate of species. And much
the total number of viral species on of this information
earth [2]. In addition to the paucity is derived from
of data on viral diversity, little is symptomatic hosts, yet
known about the level of mixed virus only a small fraction
infections or temporal patterns of virus of viruses probably
accumulation in native plants. For cause disease [5].
both social and scientific reasons, it is Furthermore, much
important to extend our knowledge of of the data gathered
7?fc
viruses and their hosts beyond those on viruses come from
DOI: 10.1371/joui nal.pbio.0040080.g001
combinations currently known to monocultures, which
cause disease to those that may cause favors a low diversity. Figure 1. Frequenciesof Sources of Plants from Which
disease in the future (i.e., emerging Thus, the data gathered Recognized Plant Viruses Were Initially Isolated
threats). In addition, we need to gain a so far have not only
greater understanding of the potential been heavily skewed toward crop-
later be recognized as the origins
for mutualistic interactions between affecting viruses, but also toward
of future crop scourges. Knowledge
viruses and their hosts. That is, we standard, laboratory-strain, phenotype-
now of their existence and ecology
traditionally view viruses as parasites, producing viruses. The presence of
will allow us to better prepare and
which is not surprising given their viruses in plants seems to be relatively
prevent the catastrophic outcomes
prominent role as pathogens, but this common—for example, approximately
often associated with such outbreaks.
is not always the case. Consider, for 60% of plants surveyed in a Costa Rican
example, polydnavirus-braconid wasp region containing about 7,000 plant
interactions, in which the virus carries species total were positive for double-
the essential genes required to suppress stranded RNA, a marker suggesting the Citation: Wren JD. Roossinck MJ. Nelson RS. Scheets
K, Palmer MW. et al. (2006) Plant virus biodiversity
the immune system of the lepidopteran presence of viruses (M.J. Roossinck, and ecology. PLoS Biol 4(3): e80.
hosts of the wasp [3]. This is a frontier unpublished data). Taken together,
that is largely unexplored. The these observations suggest a huge gap DOI: 10.1371/joui nal.pbio.0040080
Plant Virus Biodiversity and Ecology in our overall understanding of viral Copyright: © 2006 Wren et al. This is an open-access
(PVBE) project has been initiated diversity, evolution, and ecology. article distributed under the terms of the Creative
to survey the biodiversity of viruses Commons Attribution License, which permits
Closing this gap begins with a broad unrestricted use. distribution, and reproduction in
affecting vascular plants, including any medium, provided the original author and source
their endophytic fungi, in The Nature cataloging and study of viruses affecting are credited.
wild plants, whether symptomatic
Conservancy's Tallgrass Prairie Preserve
or asymptomatic, to gain a more Abbreviation: PVBE. Plant Virus Biodiversity and
of Oklahoma, home to over 700 plant Ecology
objective view of virus populations
species. Plants are an ideal starting
in nature. Ostensibly, it ends with a Jonathan D. Wren is in the Advanced Center for
point for studies on virus ecology since
GenomeTechnology. Stephenson Research and
better understanding of the mutualistic
they are immobile and can be readily Technology Center. Department of Botany and
resampled. Viral screening is done interactions between viruses and their Microbiology, the University of Oklahoma. Norman.
hosts. Newly discovered viruses will Oklahoma. United States of America. Marilyn J.
using double-stranded RNA analysis,
Roossinck and Richard S. Nelson are at the Samuel
provide information for those doing
cloning, sequencing, and microarray Roberts Noble Foundation. Plant Biology Division.
analysis. The PVBE effort is not basic research on the mechanisms of Ardmore. Oklahoma. United States of America. Kay
virus replication, translation, particle Scheets and Michael W. Palmer are In the Department
directed toward studying economically of Botany. Oklahoma State University. Stillwater.
assembly, and movement, as well
important or symptomatic plants, Oklahoma. United States of America. Ulrich Melcher
as provide tools for biotechnology is inthe Department of Biochemistry and Molecular
both of which are already heavily
(e.g., potential new vectors for gene Biology. Oklahoma State University. Stillwater.
studied. Information in Figure 1, for Oklahoma. United States of America.
knockdown studies through virus-
example, summarizes the initial plant
source of viruses cataloged in the Viral induced gene silencing). It is possible * To whom correspondence should be addressed. E-
that some of these new viruses may mall: [email protected]; u-melcher-4@
alumnl.uchicago.edu
). PLOS Biology | www.plosbiology.org 0314 March 2006 | Volume 4 | Issue 3 | e80
Gathering information on these viruses their hosts, viruses could potentially of data from The Nature Conservancy's
will also increase our ability to do be prime drivers of evolutionary Tallgrass Prairie Preserve area alone,
more extensive sequence comparisons change. The degree to which viruses but the addition of other geographical
between viruses, thereby allowing better have determined micro- and macro- areas will eventually provide a much
predictions for active site identities evolutionary patterns in vascular plants bigger picture of continental and
within viral proteins, and to identify is mostly unexplored, and the relevant global trends in plant virus biodiversity
novel viral proteins and their functions. questions are not obvious. Comparing and ecology, a new and emerging field
Not only will these efforts help us virus phylogenies to plant phylogenies of study that will hopefully enable us to
understand virus ecology, but there is will allow us to generate hypotheses answer these important questions. •
also great potential for revolutionizing about the nature of their coevolution
plant ecology. The extended phenotype and to push ecology beyond the simple Acknowledgments
of a virus may affect a plant's local concepts of competition, mutualism, Funding. The PVBE effort is funded
adaptation to its environment. parasitism, and prédation. by NSF Grant Number EPS-0447262 and
Endophytes, mycorrhizae, or other The PVBE effort faces multiple supported by the Oklahoma Agricultural
symbionts could potentially mediate challenges, including creating Experiment Station whose director has
such interactions. Given that many resources for an effort sustainable approved the manuscript for publication.
Competing interests. The authors have
plant viruses are generalists with beyond the funding period and
declared that no competing interests exist.
respect to host species, it is theoretically providing tools for the analysis of
possible that such effects may be geographic and temporal infection
References
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