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Poster: Biology & Disease Mgmt: Virology


Genetic diversity, host range and disease resistance to the emerging Tomato mottle mosaic virus on tomato
X. SUI (1), R. Li (1), C. Padmanabhan (1), K. Ling (1) (1) USDA-ARS, U.S. Vegetable Laboratory, U.S.A.

Since its first discovery in 2013 in Mexico, Tomato mottle mosaic virus (ToMMV), a new tomato-infecting tobamovirus is now present in a number of countries (i.e., Brazil, China, and Israel) and several states in the U.S. There is little information available on the molecular and biological properties of this emerging virus. With approximately 80-85% nucleotide sequence identity to two other common tobamoviruses, Tomato mosaic virus (ToMV) and Tobacco mosaic virus (TMV), there is a need to understand the genetic diversity and serological and biological properties of this emerging virus in order to develop a species-specific detection method, and to assess disease resistance durability in tomato cultivars. Comparative host range evaluation showed similarity in host species infected by three tobamoviruses. However, ToMMV was more aggressive on host plants than that of TMV and ToMV. To evaluate whether the emerging ToMMV could break the disease resistance, three commercial tomato cultivars were screened along with control Moneymaker tomato through mechanical inoculation. We observed different responses in tomato cultivars to the three tomato-infecting tobamoviruses. ToMMV exhibited aggressiveness and broke the resistance in a tomato cultivar that had demonstrated full resistance to both TMV and ToMV. This resistance breaking in tomato by the emerging ToMMV presents a serious concern for tomato growers. The mechanism of such resistance breaking will be discussed.