Fig. 1

MaUPL6 modulates MpICE1 stability via a ubiquitination pathway, regulating the response to Fusarium wilt in banana. A Phylogenetic analysis of the HECT ubiquitin-protein ligase MaUPL6 and the UPL gene family in Arabidopsis thaliana. The phylogenetic tree was constructed using the Maximum Likelihood method with MEGA 7.0 software. B Expression levels of MaUPL6 in dsRNA- and water-treated banana leaves determined by qRT-PCR analysis. Data are presented as mean ± S.E. from three biological replicates, with statistical significance determined by a two-tailed Student’s t-test (***P < 0.001). C Visual disease symptoms and (D) quantification of necrosis area in banana leaves following treatment with MaUPL6-dsRNA and water, after a Fusarium wilt inoculation. Necrosis areas were calculated using ImageJ V1.8.0 software. Data are presented as mean ± S.E. from three biological replicates. Statistical significance is indicated by different letters (P < 0.05) by Duncan's multiple range test. E Yeast two-hybrid (Y2H) assay demonstrating the interaction between MpICE1 and MaUPL6. F Subcellular localization of MpICE1 and MaUPL6 in tobacco leaf epidermal cells. Scale bar = 50 μm. G Bimolecular fluorescence complementation (BiFC) further confirmed the physical interaction between MpICE1 and MaUPL6. Scale bar = 50 μm. H In vitro, a ubiquitination assay showing MpICE1 polyubiquitination by MaUPL6 was detected via immunoblotting with an anti-MBP antibody