The haplotype-resolved genome of Swinglea glutinosa and pangenome analysis provide insight into resistance to citrus Huanglongbing
Year: 2026
Type: article
Abstract: Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus ( C Las), is the most devastating citrus disease worldwide, and all commercial varieties are susceptible to HLB. Swinglea glutinosa , a citrus relative, is resistant to C Las, but the genetic basis of its HLB resistance remains unknown. We completed a high-quality, haplotype-phased chromosome-level genome of S. glutinosa. We conducted a pangenome analysis with 25 citrus and citrus-relative accessions and identified a pan-NLRome of nucleotide-binding domain leucine-rich repeat (NLR) immune receptors representing 19,476 NLR genes. Genes specific to HLB-resistant citrus genotypes were enriched for CoA-ligase activity and auxin transport, and HLB-resistant genotypes consistently carried fewer NLRs. S. glutinosa additionally showed significant expansion of Pathogenesis-Related Protein 1 ( PR1 ) genes, lineage-specific antimicrobial peptides, and unique genes enriched for the cullin-RING ubiquitin ligase complex. In susceptible Citrus sinensis most differential NLR expression occurred at late infection stages, predominantly among coiled-coil NLRs. A single core CNL orthogroup, expanded in C. sinensis and uniformly induced upon infection, accounted for most of this response, indicating that NLR expansion and induction are not sufficient for resistance to HLB. These results will support future functional studies of HLB resistance mechanisms and provide genomic information to facilitate development of HLB-resistant citrus varieties through traditional and biotechnological approaches.
Source: Frontiers in Plant Science
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W7221783539