Viral diseases in plants offer advantageous platforms for virology work, which is why returning guest Marilyn J. Roossinck pushed her research focus in their direction. Her knowledge of virus, plant, and fungus interactions adds depth to Richard's continued collection of expert views on virus functions and habits in preparation for his book.

She discusses

• Roles viruses have played in evolution to shape us and how evolution and adaptation have shaped viruses;
• Fascinating examples, such as how insects work in the transmission of plant viruses; and
• Surprising functions, such as how the cucumber mosaic virus results from three separate viral particles that infect together to form the genome capable of infection.

Because plants are inexpensive, abundant, and easy to fit in a blender, they provide an excellent subject for virologists. Therefore, plant pathologist Marilyn J. Roossinck enlightens any attempt to understand virus behaviors. She's a professor of Plant Pathology and Environmental Microbiology at the Center for Infectious Disease Dynamics at the Huck Institute of Life Sciences at Penn State University.

After introducing her motivation for embracing this field, she helps Richard along his quest for a bigger picture of virus capabilities. Through examples of symptoms of viral diseases in plants and animals, she discusses topics like the percentage of our genome that was converted from retrovirus RNA; these genes insure mammalian survival, making placental development possible.

As she discusses human organisms as holobionts, listeners can get a much better understanding of the intricate beings we and all living organisms really are. For example, some fungal diseases in plants work with viruses for evolutionary adaptations such as the ability to survive heat. She mentions a virus discovered at Yellowstone that, if a fungus is present along with the virus, lends heat tolerance to certain plants.

Similarly, the cholera bacteria in humans is only pathogenic when accompanied by a phage. In the midst of these interesting examples, she discusses her thoughts on virus mechanisms for entry and infection, viruses' ability to communicate or signal across cells, and the existence of "helper" viruses with different roles. 

For more about her work, see The Roossinck Lab website and search her name in Google.

Available on Apple Podcasts: apple.co/2Os0myK