Spanish to English Law/Patents Law (general) Lawsuit against companies for misuse of land

I have never come across the term 'mi instituyente" before. It is a legal document from Argentina. I assume it means the equivalent of "my client", as the narrator is the legal representative of the plaintiff.

Here are some examples of where it appears:

"Mi instituyente reitera que acciona en procura de que de ordene a las demandadas:"
"Mi instituyente imputa su autoria a cada una de las empresas..."
"Mi instituyente ha echado mano fundamentalmente a informes, dictamenes..."

I am looking for the equivalent term in English. Thanks!