truncate string from a certain character in R

I have a list of strings in R which looks like:

WDN.TO
WDR.N
WDS.AX
WEC.AX
WEC.N
WED.TO

I want to get all the postfix of the strings starting from the character ".", the result should look like:

.TO
.N
.AX
.AX
.N
.TO

Anyone have any ideas?