Oxidoreductase involved in the biosynthesis of ergot alkaloid biosynthesis. Catalyzes the oxidation of chanoclavine-I in the presence of NAD(+) resulting in the formation of chanoclavine-I aldehyde. Ergot alkaloids, which are produced by endophyte fungi, can enhance plant host fitness, but also cause livestock toxicosis to host plants. chanoclavine-I + NAD(+) = chanoclavine-I aldehyde + H(+) + NADH Alkaloid biosynthesis; ergot alkaloid biosynthesis. Homotetramer. Belongs to the short-chain dehydrogenases/reductases (SDR) family.