Cellulose synthase superfamily key in DAMPs-triggered immunity against Sclerotinia stem rot in Brassica napus

• This study reveals the BnCESA superfamily’s dual-phase defense role in Brassica napus against Sclerotinia stem rot (SSR), identifying 15 SA/JA-responsive core genes and 7 functional genes mediating DAMP (CB/XOS/OG)-triggered immunity (DTI), providing SSR breeding targets. Genome-wide analysis of 92 BnCESA genes (7 subfamilies) highlights conserved catalytic/regulatory domains (DxD/TED/QxxRW) linking cell wall biosynthesis to immunity. Fifteen genes drive biphasic SA/JA defense, reducing lesions by 50%, while 7 core genes integrate cell wall integrity and immune signaling. The cellulose synthase (CESA) superfamily, critical for cell wall biosynthesis and immunity, is poorly characterized in Brassica napus resistance to Sclerotinia stem rot (SSR). We genome-wide identified 92 BnCESA superfamily genes, phylogenetically clustered into seven subfamilies (BnCESA, BnCSLA-BnCSLG). Structural analysis revealed conserved catalytic (DxD, TED) and regulatory (QxxRW) domains polysaccharide synthesis and immune responses. Intraspecific synteny analysis revealed non-uniform gene distribution across chromosomes, while interspecific comparison with Arabidopsis thaliana, Brassica rapa, Brassica oleracea , and Oryza sativa showed high collinearity with Brassica species (75-159 syntenic pairs) but limited conservation with rice (2 pairs), underscoring evolutionary conservation within Brassicaceae. Promoter cis -elements showed enrichment of jasmonic acid (JA)- and salicylic acid (SA)-responsive motifs, aligning with infection-stage expression dynamics. Transcriptomic profiling identified 36 infection-responsive genes, with 15 core candidates (e.g., BnCSLG2c, BnCESA3b, BnCSLD3d, BnCSLC8a ) driving biphasic defense: SA-mediated early responses (6-24 hpi) transitioning to JA-dominated late resistance (36-60 hpi), reducing lesion expansion by up to 50%. Oligosaccharide-derived damage-associated molecular patterns (DAMPs)—cellobiose (CB), xylooligosaccharides (XOS), and oligogalacturonides (OG), activated distinct programs: CB induced sustained responses (0-60 hpi), OG prioritized wall remodeling (48-60 hpi), and XOS synchronized with circadian-regulated defenses. Molecular docking and comparative expression profiling in resistant/susceptible rapeseed varieties predicted seven core genes ( BnCSLG2c, BnCSLC8a, BnCESA6b, BnCESA6a, BnCESA5b, BnCESA3b , and BnCSLD3d ) as potential integrators of cell wall integrity and immune signaling. Our finding provides potential genetic resources for precision breeding of SSR-resistant rapeseed.