Critical Sterility-inducing Temperature of Rice Affected by tms5 Mutation Site

  Objective   Effects of tms5 mutation site and related genetic regulatory factors in rice on the critical sterility-inducing temperature (CSIT) of the plant were investigated.

  Method  Eleven CRISPR/Cas9 sequentially numbered T501 through T511 were designed to target 6 exons of tms5 to create mutants of Nipponbare (NIP, Oryza sativa ssp. Geng) and Minghui 86 (MH86, O. sativa ssp. Xian). Pollen male fertility and seed setting rate of the mutants were monitored under long day and high temperature field conditions in early August in Fuzhou (NHT) or at 22, 24, and 28 ℃ in phytotrons to identify the CSIT.

  Result   The CSIT of the NIP mutants were higher than 28 ℃, while that of the MH86 mutants between 22 ℃ and 28°C. The tms5-1 T501 mutant had a significantly higher CSIT than the genetically identical tms5-2 counterparts T502, but the other 9 tm5 and the tm5-2 mutants did not differ on it. Expressions of the 3 Ub_L40 in young panicles were lower in the tms5-1 than the tm5-2 mutants of either rice varieties.

  Conclusion   It appeared that the CSIT of tms5 mutants was affected by the genetic factors as well as the mutation site as the tms5-1 mutant T501 was shown significantly differed from the others.