The genetic stability of rice without fusion reproductive hybrids was systematically studied

Recently, the genome editing and fusion-free reproductive innovation team of China Rice Research Institute propagated non-fusion reproductive hybrid rice materials to the 4th generation, and compared different generations of cloned materials from the levels of plant phenotype, genome, methylation, transcriptome and subgenomic transcription, which confirmed the genetic stability of non-fusion reproductive hybrid rice between different generations, and laid a theoretical foundation
for the future application of artificial non-fusion reproductive system in crops.
The research was published online in
Plant Communications.
In 2019, the team established an artificial fusion-free reproductive system in hybrid rice, achieved the fixation of heterozygous genotypes, and obtained cloned seeds of hybrid rice for the first time, proving the feasibility
of self-retention of hybrid rice.
However, it is unclear whether the superior traits of artificial non-fusion reproductive hybrid rice are stably inherited
across generations.
The solution of this problem is an important prerequisite
for the production and application of non-fusion reproductive hybrid rice in the future.
The researchers used four consecutive rice planting seasons to reproduce artificial fusion-free reproductive hybrid rice material to the third generation, and then determined the ploidy
of the 0th, 1st, 2nd and 3rd generation non-fusion reproductive hybrid rice material plants with the help of flow cytometry.
The results showed that each generation of hybrid rice plants maintained the fusion free reproductive characteristics
.
Next, the researchers focused on different generations of diploid cloned plants planted in the same season, and investigated important agronomic traits such as panicle stage, number of tillers, plant height, panicle length, number of grains per panicle and weight of 1,000 grains, and found that they were phenotypically similar
.
Thus, in the plant phenotype, the cloned plant offspring maintained the dominant phenotype of heteroseeds
for 1 generation.
Subsequently, the researchers revealed the genetic stability
of the fusion-free reproductive system from the molecular levels of genome-whole, methylation, transcriptome, and subgenome transcription expression.
The research was supported
by the National Natural Science Foundation of China, the Youth Innovation Special Project of the Chinese Academy of Agricultural Sciences, and the Yazhou Bay Seed Laboratory of Hainan Province.

Fig.
1 Multi-generation hybrid rice clones were obtained by propagation

Fig.
2 Comparison of hybrid rice plants of different generations