Field extraction stanza help in props.conf?

I have the username filed extraction as follows in the props.conf which extracts the username:- [sourcetype_X] EXTRACT-XYZ = username="(?[^+\"]*)" which extracts the field as follows x12345@abc-def-ghij-01.com y67891@klm-def-ghij-01.com z45787@abc-def-ghij-01.com ABC-DEF Now what would be regex stanza to extract the username as follows from the above x12345 y67891 z45787 ABC-DEF