Genymotion virtual devices are all rooted and it is not possible to unroot them for the moment.
However, we may implement this feature in the future.
If you need or would like us to implement this feature to Genymotion, feel free to fill our feature request form: https://forms.gle/1jsegyt4xr33Mt3z6.
Note
In some cases, it is possible to hide root from an application. To do so, please refer to:
How to use Xposed/Edxposed to hide root access from an application? (Genymotion Desktop)
How to use Xposed/Edxposed to hide root access from an application with Genymotion Cloud SaaS?
How to use Xposed/Edxposed to hide root access from an application on Cloud PaaS image?