Abstract:Villosiclava virens, the causal agent of rice false smut, produces ascospores in sexual propagation, which could be one of the primary infection sources of the disease. To better understand its sexual life cycle, the mating-type genes of V. viren were initially studied to reveal its sexual propagation in this paper. The 185 base-pair (bp) conserved coding sequence of housekeeping α-domain of mat1-1-1 mating-type protein was cloned, and this sequence had a similarity of 61%, 63% and 68% to that of Cordyceps militaris, Cor. bassiana and Claviceps purpurea, respectively. Two pairs of specific primers were designed according to the partial sequences of mat1-1-1 and mat1-2-1 mating-type genes in V. viren strains, the 138 bp and 220 bp length DNA fragments could be amplified by PCR respectively. Two hundred and forty single-ascospore strains isolated from three stromata on different sclerotium and 50 randomly selected field isolates of V. viren were employed in the test. And it was found that mat1-1-1 and mat1-2-1 mating-type genes existed in the alternative type of strains. The subsequent inoculation assay further proved that V. viren was a heterothallic fungus, since almost all the sclerotia and fertile perithecia were observed upon pair-inoculated strains of “mat1-1-1” and “mat1-2-1” type, and barely observed upon inoculated strains of “mat1-1-1” or “mat1-2-1” type.