TALEN-mediated Editing of Photoperiod-temperature-sensitive Male Sterility PMS3 Gene in Rice

  Objective  TALEN technology was employed to alter the original mutant region in pms3 gene of rice for creating different genotypes of small RNA osa-smR5864 mutants in studying the photoperiod-temperature-sensitive male sterility (PTGMS) phenotypes of pms3 mutants to provide information for breeding two-line sterile rice by means of targeted editing of PMS3.

  Method  The TALEN-PMS3 vector was constructed and transformed into Nipponbare and Minghui 86 with the pms3 mutants identified by sequencing. The T₂ generation of the mutants were planted under the natural long-day-high-temperature conditions in Fuzhou. The male fertility and seed setting rates of the mutants were determined.

  Result  Among the 25 transgenic plants regenerated, 4 clones of Nipponbare and 5 of Minghui 86 contained the target mutation with the mutation rates of 40% and 33.3%, respectively. The non-transgenic mutant plants were obtained in T₁ generations. The sequencing showed 3 homozygous mutation genotypes in Nipponbare and 5 in Minghui 86 background. Under the natural long-day-high-temperature, the T₂ pms3 mutants developed normal fertile pollens with a normal seed setting rate. But the pms3 mutants did not show a PTGMS similar to P64S.

  Conclusion  The multiple genotypes of pms3 mutants were successfully obtained. However, no PTGMS phenotype could be generated. It suggested that the molecular mechanism of pms3 locus regulating the rice PTGMS was highly complex.