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

SUMMARY Lactuca saligna L. is a wild relative of cultivated lettuce (Lactuca sativa L.), with which it is partially interfertile. Hybrid progeny suffer from hybrid incompatibility (HI), resulting in reduced fertility and distorted transmission ratios. Lactuca saligna displays broad‐spectrum resistan...

Full description

Saved in:
Bibliographic Details
Published in:The Plant journal : for cell and molecular biology 2023-07, Vol.115 (1), p.108-126
Main Authors: Xiong, Wei, Berke, Lidija, Michelmore, Richard, Workum, Dirk‐Jan M., Becker, Frank F. M., Schijlen, Elio, Bakker, Linda V., Peters, Sander, Treuren, Rob, Jeuken, Marieke, Bouwmeester, Klaas, Schranz, M. Eric
Format: Article
Language:English
Subjects:
Airborne microorganisms
Bremia
Chromosomes
comparative genomics
de novo genome assembly
Downy mildew
downy mildew disease
Fertility
Genome
Genomes
hybrid incompatibility
immune genes
Incompatibility
Inversions
Kinases
Lactuca - genetics
Lactuca saligna
Lettuce
lettuce breeding
Leucine
non‐host resistance
Nucleotides
Oomycetes
Pathogens
Phenotype
Phenotypes
Plant Diseases - genetics
population genetics
Progeny
Receptors
Vegetables
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:SUMMARY Lactuca saligna L. is a wild relative of cultivated lettuce (Lactuca sativa L.), with which it is partially interfertile. Hybrid progeny suffer from hybrid incompatibility (HI), resulting in reduced fertility and distorted transmission ratios. Lactuca saligna displays broad‐spectrum resistance against lettuce downy mildew caused by Bremia lactucae Regel and is considered a non‐host species. This phenomenon of resistance in L. saligna is called non‐host resistance (NHR). One possible mechanism behind this NHR is through the plant–pathogen interaction triggered by pathogen recognition receptors, including nucleotide‐binding leucine‐rich repeat (NLR) proteins and receptor‐like kinases (RLKs). We report a chromosome‐level genome assembly of L. saligna (accession CGN05327), leading to the identification of two large paracentric inversions (>50 Mb) between L. saligna and L. sativa. Genome‐wide searches delineated the major resistance clusters as regions enriched in NLRs and RLKs. Three of the enriched regions co‐locate with previously identified NHR intervals. RNA‐seq analysis of Bremia‐infected lettuce identified several differentially expressed RLKs in NHR regions. Three tandem wall‐associated kinase‐encoding genes (WAKs) in the NHR8 interval display particularly high expression changes at an early stage of infection. We propose RLKs as strong candidates for determinants of the NHR phenotype of L. saligna. Significance Statement We sequenced and analyzed the genome of the wild lettuce Lactuca saligna, which is resistant against lettuce downy mildew. We analyzed its population diversity and genetic variation, especially focusing on resistance genes and hybrid compatibility. Our results suggest new targets from L. saligna for future resistance breeding in lettuce.
ISSN:0960-7412
1365-313X
DOI:10.1111/tpj.16212