|CARROLL, JULIE - Cornell University|
|SMITH, DAWN - Cornell University|
Submitted to: Journal of General Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2015
Publication Date: 3/29/2016
Citation: Carroll, J., Smith, D., Gray, S.M. 2016. Preferential acquisition and inoculation of PVYNTN over PVYO in potato by the green peach aphid Myzus persicae (Sulzer). Journal of General Virology. 97:797-802.
Interpretive Summary: Emerging strains of Potato virus Y are more damaging to the U.S. potato industry because they can cause a tuber necrotic disease which reduces the quality of the potato and renders it unmarketable. The rapid emergence and expansive distribution of the new strains is unprecedented and the factors driving the changes are unknown. This research investigated whether aphid vectors of the virus were better able to transmit the emerging strains relative to the older strains when both were transmitted together or sequentially. The new and old strains are often present together in potato fields. We found that when both viruses were acquired by the same aphid the new strains were preferentially transmitted over the old strains. Furthermore, the new strains were more aggressive in the plant often overpowering the old strain, therefore the aphids feeding on the plant were more likely to acquire the newer strains that were more abundant in the plant. We also found that many potato cultivars were partially resistant to the older strains of the virus, but completely susceptible to the new strains. Together the data provide evidence that the new virus strains have an advantage over the older strains both in the probability of being transmitted by aphids and in ability to infect the potato plants.
Technical Abstract: In the past decade, the incidence and distribution of the recombinant, tuber necrotic strain of Potato virus Y (PVYNTN) has been increasing in the U.S. seed potato crop while the ordinary strain (PVYO) has been decreasing. The transmission efficiency of both strains was determined from two potato cultivars when acquired sequentially by the same aphid or when acquired by separate aphids and inoculated to the same plant. PVYNTN was transmitted more efficiently than PVYO and the order of acquisition or inoculation did not affect the preferential transmission of PVYNTN. When a recipient plant became infected with both strains, PVYNTN maintained higher titer than PVYO and would facilitate the acquisition of PVYNTN. Furthermore, the acquisition and transmission of PVYNTN over PVYO was enhanced in the potato cultivar that expresses a strain-specific Ny-like resistance gene that confers partial resistance to PVYO.