Morphological Analysis And Gene Mapping Of Rice (Oryza Sativa L.) OsMS7

In flowering plants, tapetum degeneration is proposed to be triggered by a programmed cell death (PCD) process during late stages of pollen development. The PCD is thought to provide cellular contents supporting pollen wall formation and to allow the subsequent pollen release. However, the molecular basis regulating tapetum PCD in plant remains poorly understood.A rice male-sterile mutant osms7 of japonica cultivar 9522 background, was obtained in M2 population treated with 60Coγ-Ray. Genetic analysis indicated that the male-sterile phenotype was controlled by a single recessive gene. The mutant had smaller white anther and failed to produce pollen. The wild type tapetum began to be degernated from the tetrad stage, and observation of tissue section showed that tapetum of osms7 was abnormally degenerated at the meiosis stage of microspore mother cells, and its tapetum became thicked at the tetrad stage. However, compared with the tapetum of wild type, .the observation of TEM indicated that the mutant tapetum became vacuolated and degraded earlier than those of wild type. TUNEL assay indicate that osms7 tapetal cells showed more strong TUNEL-positive signals at the meiosis stage, whereas, the TUNEL signal in wild type could be detected from the tetrad stage. All these data indicate that OsMS7 is a negative key...