Grain size is one of key agronomic traits associated with grain yield and grain quality. Both major quantitative trait loci GS3 and GL3.1 play a predominant role in negative regulation of grain size. In this study, a CRISPR/Cas9-mediated multiplex genome editing system was used to simultaneously edit GS3 and GL3.1 in a typical japonica rice Nipponbare. In T1 generation, we found that gs3 formed slender grain with lower chalkiness percentage, while gs3gl3.1 produced larger grain with higher chalkiness percentage. In terms of other agronomic traits, flag leaf size, grain number and grain yield of both gs3 and gs3gl3.1 mutants were affected. It is noteworthy that gs3 and gs3gl3.1 mutants both led to dramatical reduction of grain number, thereby decreased grain yield. In conclusion, these results indicated that knockout of GS3 and GL3.1 could rapidly improve grain size, but probably have some negative influences on grain quality and grain yield.
supported by the National Nature Science Foundation of China(Grant Nos.31521064 and 31961143016)
Technological Innovation Project of Chinese Academy of Agricultural Sciences(Grant No.CAASASTIP-2013-CNRRI)
Major Transgenic Projects of China(Grant No.2016ZX08001-002)
National Key Research and Development Program(Grant No.2016YFD0101801)
the Natural Science Foundation of Innovation Research Group(Grant No.31521064)。