From gametocides to gene drive: natural transmission distortion systems as tools for cereal breeding
摘要
Natural segregation distortion systems are an important yet frequently overlooked component of genome dynamics in plants. Chromosomes carrying gametocidal genes (Gc), originating from Aegilops species, represent one of the most widely studied chromosome-drive elements in cereals. By inducing chromosomal breakage in gametes that lack these genes and protecting those that inherit them, such chromosomes achieve strong preferential transmission, substantially affecting chromosome behavior in interspecific hybrids. Recent studies have revealed that, in wheat and triticale breeding, Gc systems can be used to stabilize alien chromatin and to secure the efficient introgression of resistance genes such as Lr32, Lr22, Lr39, Lr41, Pm13, Lr54, and Yr37. Their biased transmission can further support the maintenance of beneficial alleles or favorable allelic combinations within breeding populations. The activity of chromosomes bearing gametocidal genes facilitates the development of addition and substitution lines, promotes targeted chromosome rearrangements, and increases the retention of alien segments across backcross generations. The emergence of new genomic techniques has renewed interest in natural drive systems, and although homing-based drives remain limited in crops, chromosomes carrying Gc genes already provide a biologically contained and reliable mechanism of biased inheritance in polyploid cereals. This review summarizes the evolutionary and cytogenetic basis of Gc systems and highlights their relevance and future potential in chromosome engineering and cereal improvement.