Control of Tomato Spotted Wilt Virus in Floral Crops Progress Report — March 1992
Date February 19, 1992
Title of Project Control of Tomato Spotted Wilt Virus in Floral Crops
Institution where work is being conducted North Carolina State University
Amount of Endowment Grant $ 35,000
Covering Period Jan. 1992 to Dec. 1992
Anticipated Date of Project Completion/Final Report December 1992
Individual(s) Conducting Project:
(List Project Leader First)
James Moyer - Title Professor
Telephone Number 919-515-2735
Control of Tomato Spotted Wilt Virus in Floral Crops
James Moyer
North Carolina State University
- A. Project Objectives:
- The original proposal contained four objectives; 1) To collect TSWV-Iike
isolates from different floral crop hosts and geographic regions. 2) Develop biological and
biochemical assays for these virus-host combinations. 3) Compare the biological and biochemical
properties of floral crop-specific isolates with each other and with standard isolates of TSWV. 4)
To develop resistance to these viruses in floral crops.
TSWV-like viruses found in floral crops. We identified a new virus which has been named
Impatiens necrotic spot virus (formerly TSWV-I). This was the first report of serological diversity
in the TSWV group of viruses and was recently cited in a review of the highlights of virology (plant
and animal) for 1990. Antiserum was made for diagnostic and research purposes. We have also
collected approximately twenty TSWV-like isolates from floral crops from all over the United
States. These played an important role in improving our diagnostic tools, in providing an accurate
representation of the TSWV-like isolates in the floral crop industry and will be invaluable in
testing resistant cultivars. We have tested diagnostic approaches, both biological and serological,
developed in our lab and those developed and recommended by others for use in routine diagnosis
and for clean stock programs. Much of this information has been put to use not only by ourselves,
but also by diagnosticians in public and private plant disease clinics. We have also conducted a
thorough comparison of the different isolates. Host range studies have been completed and a
student (not supported by this grant) is currently conducting a detailed serological analysis with
polyclonal and monoclonal antibodies. A significant finding of his research is that a monoclonal
antibody which reacts with both L and I types has been identified which will hopefully lead to a
single test for all TSWV-like isolates. We have also completed the biochemical characterization of
the TSWV isolate and isolated viral genes from both serotypes which can be used to impart
resistance to these viruses. Most recently we have emphasized the development of transformation
protocols for chrysanthemum and New guinea Impatiens. Thus, we have essentially completed
Objectives 1 - 3 and initiated investigations on Obj. 4. Manuscript status is attached.
continued. Regeneration procedures for obtaining plants from leaf discs were available for two
cultivars; Hekla and Iridon. Quite recently we have had some preliminary success in transforming
Iridon with a reporter gene. Current transformation efforts are using the TSWV resistance gene.
We have also been extending these efforts to include TSWV susceptible cultivars such as Polaris.
We have developed a regeneration procedure for this cultivar as available procedures were
ineffective. We have also initiated attempts to develop a transformation system for New Guinea
Impatiens. This has been somewhat more problematic as there was no regeneration system
available suitable for transformation. Thus, we have had to begin at the very beginning. Prolific
rooting of leaf tissue explants was an initial problem, but has been overcome. We have also
overcome problems with contamination. Hormone requirements which promote callus formation
and suppress root formation have been identified. Current efforts consist of identifying hormone
requirements for shoot initiation and evaluation of strains of Agrobacterium which are used to
mediate the transformation process.
basis for diagnosis. The antisera, in a kit format, is commercially available through Agdia, Inc.
Research underway way is anticipated to lead to one kit for all TSWV-like viruses. Our current
research is directed at developing procedures for the introduction of virus resistance genes into
important floral crops. These techniques will also be applicable for the introduction of other genes
such as resistance to other viruses, herbicide tolerance, insect resistance and control of ethylene
production.
spotted wilt virus strain. Phytopathology 79:1157 (abstract).
N protein. J. General Virology 71:933-938. (cited in highlights in virology for 1990 covers both
plant and animal viruses).
isolates of the L- and I- serogroups of tomato spotted wilt virus. Phytopathology 81:521-525.
and N gene of the S RNA of a serologically distinct tospovirus. J. of Gen. Virol. 72:2597-2601.
Tospovirus (Bunyaviridae) has an ambisense genomic organization. Virology Submitted.
Agrobacterium-mediated transformation of Chrysanthemum trifoliar. In-Vitro Culture and
Horticulture Breeding Symposium. Submitted.
support and will be published soon. AFE support will be acknowledged.
TSWV-I) is in preparation.
