Compendium of Colletotrichum graminicola responsive infection-induced transcriptomic shifts in the maize

Abstract

Pathogen-induced biotic stress stands as the foremost factor undermining global agricultural productivity, and comparative transcriptomics studies are ideal for zeroing in on processes remodeled in response to the pathogen. We examined the maize-Colletotrichum graminicola pathosystem to discern the host-deployed defensive program towards this fungal pathogen. Of a total of 36,058 transcripts identified, 306 show significant differential expression (5% FDR). The differentially expressed genes are implicated in pathogenesis, stress signaling, disease defense, cell wall reinforcement, signal perception, and transduction. Comparative Gene ontological enrichment analysis of the differentially expressed genes revealed enrichment in terms involved in fungal defense, such as aminoglycan metabolism and catabolism, chitin metabolism and catabolism, cell wall macromolecule metabolic and catabolic process, response to stress and hydrolyzing o-glycosyl compounds. Subsequent analysis highlighted transcript mapping to many prominent defensive pathways like phenylpropanoid, plant-pathogen interaction, ubiquitin proteolysis, and biosynthesis of secondary metabolites. We observed over-expression of the lysM domain containing possible novel chitin elicitor binding protein (CEBiP) homolog C0PL67 (Uniprot identifier), and GRMZM2G056329, a Casparian strip membrane domain-like protein (CASP-like), previously uncharacterized in the maize-Colletotrichum interface, that could potentially act as a target gene for subduing pathogenesis. Further, sequence analysis of the differentially expressed genes resulted in the identification of possible, pathogenesis-relevant, de-novo motifs and effectors.