Sales and Marketing go together like hands and gloves, neither will be successful in isolation and teams within companies have to work together.
The marketing plan has to feed the sales plan and vice-a-versa.
Too many companies work separately and the best companies have a joined up approach. Each area has its own set of skills and part to play.
This is where Marketing can help a sales person:
It is important that the sales rep understands the role and place of marketing.
A few interesting reads to understand marketing strengths
http://blog.thewholebraingroup.com/3-sales-team-marketing-team
http://www.pr2020.com/blog/how-marketing-can-support-the-sales-process
https://blogs.oracle.com/marketingcloud/5-ways-marketing-can-help-sales-succeed-v2