Identification and editing of a hybrid lethality gene expands the range of interspecific hybridization potential inNicotiana

摘要

Key message Identification and inactivation of hybrid lethality genes can be used to expand the available gene pool for improvement of a cultivated crop species. Hybrid lethality is one genetic mechanism that contributes to reproductive isolation in plants and serves as a barrier to use of diverse germplasm for improvement of cultivated species. A classic example is the seedling lethality exhibited by progeny from theNicotiana tabacum x N. africanainterspecific cross. In order to increase the body of knowledge on mechanisms of hybrid lethality in plants, and to potentially develop tools to circumvent them, we utilized a transposon tagging strategy to identify a candidate gene involved in the control of this reaction.N. tabacumgeneNt6549g30was identified to code for a class of coiled-coil nucleotide-binding site-leucine-rich repeat (CC-NBS-LRR) proteins, the largest class of plant defense proteins. Gene editing, along with other experiments, was used to verify thatNt6549g30is the gene at theN. tabacum Hybrid Lethality 1(NtHL1) locus controlling the hybrid lethality reaction in crosses withN. africana. Gene editing ofNt6549g30was also used to reverse interspecific seedling lethality in crosses betweenN. tabacumand eight of nine additional tested species from sectionSuaveolentes. Results further implicate the role of disease resistance-like genes in the evolution of plant species and demonstrate the possibility of expanding the gene pool for a crop species through gene editing.