Mo. Rev. Stat. § 49.550
There shall be and there is hereby created a statutory mortgage lien upon the buildings, land and appurtenances acquired or constructed under the provisions of sections 49.520 to 49.580 in favor of the holders and owners of the bonds. The buildings and land so acquired or constructed and the appurtenances thereto shall remain subject to the statutory lien until payment in full of the principal and the interest contracted to be paid and according to the tenor thereof. Any holder of the bonds or of any of the coupons may, either at law or in equity, protect and enforce the statutory mortgage lien hereby conferred, and may by suit, action, mandamus or other proceedings, enforce and compel performance of all duties set forth herein, including the making and collecting of sufficient charges for the use of the buildings, the segregation of the income and revenue, and the application thereof to satisfy the obligations.
§ 49.550, RSMo