sentences:  Additionally, stimulating both of the mating types by TSA promotes synthesis of β-carotene.As β-carotene is produced, it becomes a precursor of trisporoid, which is a pheromone for "B. trispora".Production of β-carotene promotes a positive feedback process that further stimulates carotenogenesis and the production of trisporoid which serves as a β-carotene increasing substance.