Genome-wide identification and expression analysis of RBR-type ubiquitin ligase family genes reveal the role of ZmIBR10 in maize disease resistance

As a key enzyme involved in the ubiquitination modification of proteins, ubiquitin-protein ligase E3 (E3) plays a crucial role in various important physiological processes, including plant growth and development. However, systematic analysis of the maize In-between-RING fingers (IBR) family members and their functions in stress responses remains limited. Using bioinformatics methods, we characterized the evolutionary relationships, conserved domains, tissue-specific expression, and expression patterns under various stress conditions of the maize IBR family genes. The results revealed that the maize genome contains 18 IBR family genes, which are classified into four categories: A1, A2, B1, and B2, all of which possess conserved E3 ligase motifs. The expression levels of IBR family genes exhibited significant variations across different tissues, stress treatments, and treatments with jasmonic acid and salicylic acid. It is hypothesized that maize IBR family genes may play a vital role in maize growth and development, as well as in the response to various biotic and abiotic stresses. Notably, the expression level of ZmIBR10 was significantly up-regulated upon infection by Fusarium verticillioides, Aspergillus flavus, and Fusarium graminearum, indicating its involvement in maize resistance to pathogen infection. Further analysis of mutants confirmed the essential role of ZmIBR10 in maize resistance to Curvularia lunata, Cochliobolus carbonum, and Fusarium graminearum. This study provides a valuable reference for further elucidating the function and mechanisms of IBR family genes in maize.