Based on what you read so far in Of Mice and Men, how might Curley's wife be the ignition switch for the conflict?

It makes sense that Curley's wife can be seen as a trigger for the conflict in the novel.

Curley's wife is very unhappy with her life at the ranch. In chapter 2, when Slim notifies her that Curley is looking for her, Steinbeck writes that she adopted a "suddenly apprehensive" demeanor.  She is clearly uncomfortable with her husband.  As a result, she is constantly in the bunkhouse, talking to the other men. Her restlessness has the tendency to lead to trouble, something that George points out in chapter 3: 

She’s gonna make a mess. They’s gonna be a bad mess about her. She’s a jail bait all set on the trigger. That Curley got his work cut out for him. Ranch with a bunch of guys on it ain’t no place for a girl, specially like her.

Later on in chapter 3, Carlson affirms this when he tells Curley that if she continues to "hang around bunkhouses," he will have "som'pin on your hands."  

These textual examples foreshadow how Curley's wife is going to be involved in some conflict.  In some capacity, she will act as the trigger or ignition switch for what is going to happen.  It is clear that Curley's wife is not going to remain separate from the men because of the dissatisfaction she feels about her own life.  Steinbeck sets up Curley's wife on a crash course with the men in the bunkhouse.  The results of this will not be good.  Like so many in the novella, the hopes of Curley's wife will come into conflict with reality.