Fig 4.
Internalization of MNV-1 in romaine lettuce grown hydroponically. Feed water was inoculated with MNV-1 stock to a starting titer on day 0 of 2.5 × 106 PFU/ml. The titer of the feed water was monitored throughout the 14-day study period and is reported as PFU/ml. At each time point, roots, shoots, and leaves of romaine lettuce were harvested, homogenized with liquid nitrogen and mortar and pestle, and resuspended in 5 ml of sterile PBS. Sample homogenate was then subjected to centrifugation at 1,000 × g for 30 min, and the supernatant was tested for infectious viral particles. Data shown in the internalization kinetics plot were determined by plaque assay, and results are reported as PFU/g. Data points are the averages of three replicates. Error bars represent ±1 standard deviation.