[Binari] non-greedy perl regex

Hi! How can I make this Regex greedy? my ($seq) = ($var =~m/^(.*_{0,1}\d+)\s.*/); if $var is "ara_prot.tfa_3154 | AT1G26170.1 | no family", I want to cut after the first whitespace so that $seq becomes be "ara_prot.tfa_3154" and not "ara_prot.tfa_3154 | AT1G26170.1". I don't know where/ how to include the ? for non-greedy search. I would want to do it with round brackets, but that violates the round brackets I already use for getting a part of the string, no? Thanks for any suggestions! Esther.