org-export-with-emphasize

org-export-with-emphasize is a variable defined in `ox.el'.
Its value is

t

Documentation:
Non-nil means interpret *word*, /word/, _word_ and +word+.

If the export target supports emphasizing text, the word will be
typeset in bold, italic, with an underline or strike-through,
respectively.

This option can also be set with the OPTIONS keyword,
e.g. "*:nil".

You can customize this variable.