Identification of a New Rice Low-Tiller Mutant and Association Analyses Based on the SLAF-seq Method

By studying the regulatory mechanism by which rice tillers are controlled, many rice mutants were described as providing important insights into the investigation of tillering control. In this study, we surveyed a new rice mutant produced by ethyl methane sulfonate induction, designated as Oryza sativa low-tiller 1 (oslt1), which had been planted to the fourth generation and proved to stably inherit the low-tillering trait. The statistical analysis of the number of tillers in oslt1 showed that there was a significant lack of tillering in the mutant lines, with the average number being 2.33 as opposed to 8.00 in wild-type plants. The data from a series of crossed populations, including F-2 populations produced by selfing of the offspring of oslt1 x ptb and backcross populations of the F-1 generation x oslt1, indicated that a single recessive gene controlled the low-tillering trait. To locate the recessive gene, the crossed population in the F-2 generation from two parents, oslt1 and Peiai 64, was constructed and the population was used for bulked segregate analysis based on specific locus amplified fragment-sequencing (SLAF-seq) method. The results showed that approximately 100 differential markers were procured by analyzing 7437 polymorphic SLAFs and 1 primary region associated with low-tillering characteristics located on Chr12. In the associated regions, there were 34 candidate genes of 0.24 Mb that might be related to the number of low tillers in oslt1 plants. All of these results are necessary for further fine mapping for this low tillering-related gene. In addition, these identified SLAF-tags will be valuable for marker-assisted selection in rice breeding.