The transcription factor SiROCX controls a monocot-specific CAZyme program for host 1 cell wall remodeling during symbiotic root colonization

ABSTRACT: Intracellular accommodation of beneficial fungi requires controlled remodeling of host cell walls while avoiding activation of plant immune responses. During colonization of monocot roots, the endophytic fungus Serendipita indica induces a suite of carbohydrate-active enzymes (CAZymes) targeting xylan and cellulose. Weighted gene co-expression network analysis identified the basidiomycete-specific transcription factor SiROCX as a key regulator of this monocot-adapted program. DNA affinity purification sequencing (DAP-seq) defined the SiROCX binding motif and revealed a CAZyme-enriched target regulon. Inducible SiROCX overexpression selectively activated motif-containing CAZyme genes and markedly enhanced xylanase and cellulase activities on xylan and native barley root cell walls. Premature activation of this program triggered expression of a plant immune marker despite comparable fungal biomass, indicating that precise temporal control of CAZyme deployment is required to maintain symbiotic compatibility. Together, these findings identify SiROCX as a central regulator of a monocot-adapted cell wall–degrading secretome and reveal a basidiomycete- specific regulatory module that coordinates host cell wall remodeling with immune-compatible symbiotic colonization.

INSTRUMENT(S):

ORGANISM(S): Serendipita Indica Dsm 11827

TISSUE(S): Protein Secretion

SUBMITTER: Proteomics Facility  

LAB HEAD: Prof. Dr. Alga Zuccaro

PROVIDER: PXD075761 | Pride | 2026-10-20

REPOSITORIES: Pride