Transmission of tobacco mosaic virus in recirculating hydroponic system

Abstract

The possible pathway of transmission of tobacco mosaic virus (TMV) from diseased plants to healthy plants in two hydroponic systems, deep flow culture (DFC) and container culture (CC), was investigated in this study. The tested plants were tobacco ( Nicotiana tabacum cv. Samsun-nn and cv. Xanthi), tomato ( Lycopersicon esculentum cv. Alchan), and hot pepper ( Capsicum annuum cv. Dahong). The longevity in vitro and the dilution end point of the virus in the hydroponic solution were 5 days and 10 −4 (w/v), respectively. When inoculum source plants and tested healthy plants were grown side by side in the same gully or containers, typical TMV symptoms appeared on the tested plants in 2 weeks. The presence and concentration of the virus in the tissues of the tested plants could be detected by DAS-ELISA. It was noticed that roots of the inoculum source plants grafted to those of the tested plants during growing period. However, when both inoculated plants and healthy plants were grown separately, and their root tips were either removed or remained intact, no transmission of the virus from the inoculum source plants to the tested healthy plants occurred even though they shared the same recycled nutrient solution. These results indicate that the virus in a recirculating hydroponic system could be transmitted from virus-diseased plants to healthy plants mainly via root-tip grafting but was hardly transmitted through regularly renewed hydroponic nutrient solution.