I came to know SyncTrayzor from http://alternativeto.net/software/google-drive/?license=opensource as an open source alternative for Google Drive.
I thought it could be configured to sync local files with Google Drive, is this possible?
No, syncthing is peer to peer, not peer to google drive.
You’ll also find Dropbox listed as an alternative to Google Drive, but that doesn’t mean that Dropbox talks to Google Drive.