Double haploid (DH) technology, which is based on in vivo haploid induction, enables the fixation of recombinant haplotypes within two generations, thereby greatly increasing crop breeding efficiency. Although haploid plants can be produced from some legumes via an in vitro anther/microspore culture approach, there has been little progress regarding an in vivo (in seeds) haploid induction system in this family, hindering the application of DH technology to legume crops. In this study, using the model legume Medicago truncatula as a genetic system, we demonstrated that CRISPR-Cas9 mediated mutation in the M. truncatula ZmDMP-like genes MtDMP8 and MtDMP9, which specifically expressed in M. truncatula anther and pollen and localized to the plasma membrane, can successfully induce haploid embryo. These results firstly demonstrate that the DMP-triggered in vivo haploid induction system can be extended to legume species. Thus, our study provides a promising starting point for legume haploid gene editing and mechanistic studies of haploid induction in legumes, which may pave the way for the deployment of DH technology in legume breeding.

Article link: https://onlinelibrary.wiley.com/doi/abs/10.1111/pbi.13740