Genetic and Expression Analyses of a Male Sterile Gene <i>MGA1(t)</i> in Rice (<i>Oryza sativa</i> L. )

Abstract

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.