Genome assembly and analysis of Lactuca virosa: implications for lettuce breeding.

Lettuce (Lactuca sativa L.) is a leafy vegetable crop with ongoing breeding efforts related to quality, resilience, and innovative production systems. To breed resilient and resistant lettuce in the future, valuable genetic variation found in close relatives could be further exploited.

The genome of Lactuca saligna, a wild relative of lettuce, provides insight into non-host resistance to the downy mildew Bremia lactucae.

Lactuca saligna L. is a wild relative of cultivated lettuce (Lactuca sativa L.), with which it is partially interfertile.

Patterns of Transmission Ratio Distortion in Interspecific Lettuce Hybrids Reveal a Sex-Independent Gametophytic Barrier.

Interspecific crosses can result in progeny with reduced vitality or fertility due to genetic incompatibilities between species, a phenomenon known as hybrid incompatibility (HI). HI is often caused by a bias against deleterious allele combinations, which results in transmission ratio distortion (TRD). Here, we determined the genome-wide distribution of HI between wild lettuce, , and cultivated lettuce, , in a set of backcross inbred lines (BILs) with single introgression segments from introgressed into a genetic background.

Bidirectional backcrosses between wild and cultivated lettuce identify loci involved in nonhost resistance to downy mildew.

The nonhost resistance of wild lettuce to lettuce downy mildew seems explained by four components of a putative set of epistatic genes. The commonplace observation that plants are immune to most potential pathogens is known as nonhost resistance (NHR). The genetic basis of NHR is poorly understood.

Effector-mediated discovery of a novel resistance gene against Bremia lactucae in a nonhost lettuce species.

Candidate effectors from lettuce downy mildew (Bremia lactucae) enable high-throughput germplasm screening for the presence of resistance (R) genes. The nonhost species Lactuca saligna comprises a source of B. lactucae R genes that has hardly been exploited in lettuce breeding.