A male gamete sterile mutant (tentatively named Male gametophyte abortion1, mga1(t)) was obtained by abnormality screening of transgenic rice materials in this study. The ratio of marker gene segregation was 1:1 by χ 2 -test and the pollen grains of the mutant were half sterile. The phenotype of pollen abortion was found co-segregating with T-DNA insertion in mga1(t) mutant, and T-DNA passed only through the female gamete. Southern blot analysis indicated that T-DNA inserted into the genome of the mutant was single copy. Flanking sequence analysis showed that T-DNA was inserted into the 5' untranslated region of a Bax inhibitor (BI)-1 like family protein gene in rice chromosome 3. BI-1 like protein gene was predicted to be involved in programmed cell death. RT-PCR expression analyses revealed that MGA1(t) gene expressed during the whole growth and development stages of rice, and had a strong expression pattern in the spikelets with the length about 0~7 mm. These results indicated that MGA1(t) gene was a male-preferential expressed gene.