$ sudo apt-get update
$ sudo apt-get install gedit-latex-plugin 

gedit-latex-plugin is installed in your system.

Make ensure the gedit-latex-plugin package were installed using the commands given below,

$ sudo dpkg-query -l | grep gedit-latex-plugin *

You will get with gedit-latex-plugin package name, version, architecture and description in a table

gedit-latex-plugin package basic information: