Convert an underlined phrase to a quoted phrase?

Can I automate adding quotation marks around a phrase? I was thinking in the manner that a phrase can be converted from sentence to title case, for example?

I have many of these, suitable for citations:
Landscape Plants for the Gulf and South Atlantic Coasts
(that’s supposed to be underline, not sure how it will post.

that I need to look like this, suitable for newspaper format:
“Landscape Plants for the Gulf and South Atlantic Coasts”

Although I’m a longtime Scrivener user, I’m really just beginning to use ‘power’ features, having just completed the tutorial. Until I started a non-fiction book I used Scrivener solely for my weekly newspaper column. Nothing fancy.

I looked at searching by format, which works great for words but not for phrases. I also spent some time trying to create a Preset, which didn’t work.

I’m running Yosemite 10.10.1 and Scrivener 2.6.

Presets cannot add text, they only change formatting. There is no way to do this natively in Scrivener. The way I would approach it myself is by using a macro program that searches for underlined text (not sure why you had difficulties with that and phrases, it should be finding any contiguous span of text that matches the formatting criteria) and adds quotes around the selected result.