Effector Proteins of Funneliformis mosseae: Unravelling Plant-Fungal Interactions through Reference-Based Transcriptome Analysis, In vitro Validation, and Protein‒protein Docking Studies

Abstract

Background Arbuscular mycorrhizal (AM) fungi form a highly adaptable and versatile group of fungi found in natural and man-managed ecosystems. Cell signaling molecules are important in establishing symbiosis between host plants and AM fungi. Recent studies have illustrated that effector proteins produced by AM fungi influence host-plant defense responses during the establishment of interactions between host plants and AM fungi. Fungal effectors are secretory proteins capable of modifying host cells, suppressing host defense and promoting infection by fungi to derive nutrients from the host. The effectors are delivered to the host via diverse mechanisms and at different stages based on environmental triggers. Results Here, we carried out transcriptome sequencing of Funneliformis mosseae isolate BR221 and identified the expressed gene repertoires. The study emphasized the annotation of putative effector proteins and investigation of the crucial effector proteins that interact with the candidate host targets involved in immunomodulation and facilitation of colonization in roots. A total of 120 effector proteins were identified in F. mosseae isolate BR221, of which 26 were found to be common to previously reported species of AM fungi. In silico prediction using a pathogen‒host interaction database suggested that four effectors could be crucial in establishing AM fungi-host interactions. Protein‒protein in silico interactions between the selected effectors of F. mosseae isolate BR221 and known host-plant proteins previously reported to be important in mycorrhizal association emphasized the potential role of the four selected effectors of F. mosseae in AM fungus-host interactions. Real-time expression of these effectors in F. mosseae isolate BR221 was validated using qPCR experiments. Conclusions Through transcriptome analysis of Funneliformis mosseae isolate BR221, we identified key effector proteins central to AM fungi-host symbiosis, with four effectors underscored by in silico prediction and experimental validation as pivotal in mediating this crucial interaction.