ChIFNα regulates adventitious root development in Lotus japonicus via an auxin-mediated pathway

Adventitious roots (ARs), developing from non-root tissue, play an important role in some plants. Here, the molecular mechanism of AR differentiation in Lotus japonicus L. (L. japonicus) with the transformed chicken interferon alpha gene (ChIFN alpha) encoding cytokine was studied. ChIFN alpha transgenic plants (TP) were identified by GUS staining, PCR, RT-PCR, and ELISA. Up to 0.175 mu g/kg rChIFN alpha was detected in TP2 lines. Expressing rChIFN alpha promotes AR development by producing longer roots than controls. We found that the effect was enhanced with the auxin precursor IBA treatment in TP. IAA contents, POD, and PPO activities associated with auxin regulation were higher than wild type (WT) in TP and exogenous ChIFN alpha treatment plants. Transcriptome analysis revealed 48 auxin-related differentially expressed genes (DEGs) (FDR < 0.05), which expression levels were verified by RT-qPCR analysis. GO enrichment analysis of DEGs also highlighted the auxin pathway. Further analysis found that ChIFN alpha significantly enhanced auxin synthesis and signaling mainly with up-regulated genes of ALDH, and GH3. Our study reveals that ChIFN alpha can promote plant AR development by mediating auxin regulation. The findings help explore the role of ChIFN alpha cytokines and expand animal gene sources for the molecular breeding of growth regulation of forage plants.