Domestication reduces plant immune receptor gene repertoires across lineages

Plant domestication is sometimes associated with a reduction in the diversity of immune receptor genes, critical for pathogen recognition and defense. Yet, the extent and evolutionary forces driving this pattern remain unclear. Using a comparative genomics framework, we analyzed the immune receptor gene repertoires of 15 domesticated crop species and their wild relatives, representing nine plant families. We examined both cell surface pattern recognition receptors and intracellular nucleotide-binding leucine-rich repeat receptors. Our results show that five crops—grapes, mandarins, rice, barley, and yellow sarson—exhibited significantly reduced immune receptor gene repertoires compared to their wild counterparts; however, the overall rate of immune receptor gene loss reflected the background rate of gene loss. Despite this, there is a positive association between domestication duration and immune receptor gene loss. Together, these results suggest that domestication imposes a subtle, cumulative pressure, consistent with relaxed selection rather than a strong cost-of-resistance effect. This study provides insights into how domestication impacts plant immunity, with implications for future crop breeding strategies to enhance disease resistance.