Dual-Transcriptomic, Microscopic, and Biocontrol Analyses of the Interaction Between the Bioeffector and the Pythium Soft-Rot of Ginger Pathogen .

Biological control is a promising approach to suppress diseases caused by spp. such as Pythium soft rot of ginger caused by . Unusually for a single genus, it also includes species that can antagonize plant pathogens, such as . We investigated if a new isolate of could antagonize , what changes occurred in gene expression when (antagonist) and (host) interacted, and whether could control soft-rot of ginger caused by . An isolate of , GAQ1, recovered from soil could antagonize in a plate-based confrontation assay whereby became non-viable. The loss of viability of coupled with how hyphae could coil around and penetrate the hyphae of , indicated a predatory interaction. We investigated the transcriptional responses of and using dual-RNAseq at a stage in the confrontation where similar levels of total transcripts were measured from each species. As part of the transcriptional response of to the presence of , genes including a subset of putative Kazal-type protease inhibitors were strongly upregulated along with cellulases, elicitin-like proteins and genes involved in the repair of DNA double-strand breaks. In , proteases, cellulases, and peroxidases featured prominently in the upregulated genes. The upregulation along with constitutive expression of proteases appeared to be responded to by the upregulation of putative protease inhibitors from , suggesting a defensive strategy. Notwithstanding this defensive strategy, had a strong disease control effect on soft-rot of ginger caused by . The newly isolated strain of is a promising biocontrol agent for suppressing the soft-rot of ginger. The dual-RNAseq approach highlights responses of that suggests features of a defensive strategy, and are perhaps another factor that may contribute to the variable success and durability of biological attempts to control diseases caused by spp.