Hi Om,
Is your Marketo instance set up to sync with SFDC yet? If not, I'd recommend setting that up first, and make sure that both the Account and Lead objects are being synced. When this happens, Marketo will automatically detect the field and sync it.
If you have just recently added this field, I'd recommend first making sure it is visible to the Marketo Sync user, that way it will show up in Marketo. If you are having trouble with only part of the Account Industry data syncing through, Marketo technical support may be able to flip the "Last Updated" timestamp on all of your records, which would ensure they refresh and pull in the most recent data from SFDC.
Hope this helps!
Jonathan