Cross breeding of novel Cordyceps militaris strains with high contents of cordycepin and carotenoid by using MAT genes as selectable markers

Abstract As a highly valued edible mushroom, Cordyceps militaris has attracted considerable attention because it contains a variety of bioactive ingredients. Among these bioactive substances, cordycepin and carotenoid have been the focus of research due to their high nutrient values. However, the yield of these bioactive substances evidently decreases during passage because of the easy degeneration of C. militaris. To obtain high quality strains, this study aimed to screen C. militaris strains that could highly produce carotenoid and cordycepin simultaneously. For this purpose, hybridization between two strains of C. militaris which highly produce carotenoid and cordycepin, respectively, was performed and studied currently. The high-producing strain, named ZA10-C4, was successfully obtained by screening the selectable marker MAT gene and the biological characteristics. The hybrid strain ZA10-C4 showed higher production of both cordycepin (357.166 ± 19.151 mg/g) and carotenoid (13.770 ± 0.580 mg/g) compared with the parental strains. The improved rapid gene extraction and labeling method presently used to analyze the MAT gene of C. militaris would improve the efficiency of gene identification. In addition, hybrid strain could stably retain the traits of the parental strains through cross breeding by way of natural inheritance. Therefore, this study provides a fast and stable method for the breeding of C. militaris.