CS-23.3
PLANT VIRUS INFECTION OF PHYTOPHTHORA: A SYSTEM FOR GENE EXPRESSION AND
IDENTIFYING GENE FUNCTIONS
Ju-Yeon Yoon1, Eseul Baek1, Seung-Kook Choi2, Tiziana Mascia3,4, Donato Gallitelli3,4, Peter
Palukaitis1
Department of Horticultural Sciences, Seoul Women’s University, Seoul 139-774, Korea
2Virology Unit, Department of Horticultural Environment, NIHHS, RDA, Suwon 440-441, Korea
3Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, Università degli Studi di Bari Aldo
Moro, 70126 Bari, Italy
4Istituto di Virologia Vegetale del Consiglio Nazionale delle Ricerche, Unità Operativa di Supporto di
Bari, 70126 Bari, Italy
Tobacco mosaic virus (TMV) was shown recently to be able to infect filamentous fungi, as well as to
express a foreign gene, encoding the green fluorescent protein (GFP), within the fungal cytoplasm.
TMV expressing GFP (TMV-GFP) also could silence the expression of a fungal-expressed GFP
transgene, demonstrating the use of recombinant TMV vectors as a system for gene over-expression
as well as viral-induced gene silencing in filamentous fungi. Using the same inoculation technology,
we have demonstrated that TMV can also infect Phytophthora capsici, an oomycete pathogen of
plants, with no apparent effect on the growth of the oomycete, in liquid culture or subsequently on
agar plates. Infection of P. capsici by TMV-GFP also led to the ectopic expression of GFP in P.
capsici growing in liquid culture; the infection and expression were dependent upon the reproduction
of the oomycete culture. This system is being evaluated for inhibition of specific P. capsici genes
involved in growth and development, as well as genes potentially involved in pathogenicity, by
infection of the oomycete with TMV expressing sequences derived from those P. capsici genes. In
addition, the unrelated viruses, potato virus X and pepper mottle virus, are being assessed for their
ability to infect P. capsici, as additional tools for multigene silencing. The results of these analyses will
be presented and the potential use of plant-movement-deficient TMV for biocontrol of oomycete
pathogens will be discussed.