Systematic analysis of the ShRZFP gene family and its association with tiller regulation in sugarcane

BACKGROUND: Ubiquitination modification is a core regulatory mechanism of plant growth, development and stress response. The CHY zinc finger domain-containing RING-type E3 ubiquitin ligase (RZFP) subfamily plays a unique role in plant signal integration, but its systematic research in sugarcane remains unreported. Tillering is a key agronomic trait determining sugarcane yield, while its molecular regulatory mechanism is yet to be fully elucidated. This study aimed to systematically characterize the RZFP gene family in sugarcane and explore its association with tillering regulation. RESULTS: A total of 47 ShRZFP genes were identified from the sugarcane XTT22 genome. Phylogenetic analysis divided ShRZFP proteins into 3 groups with independent expansion characteristics; segmental duplication was the main driver of family expansion, dominated by purifying selection during evolution. ShRZFP proteins harbored 2-10 conserved motifs, with consistent gene structures within the same evolutionary branch. Light-responsive elements were the most abundant cis-acting elements in ShRZFP promoters. Weighted Gene Co-expression Network Analysis (WGCNA) screened 6 candidate tillering-related ShRZFP genes enriched in the yellow module, whose co-expressed genes were significantly enriched in the photosynthesis pathway. Upstream transcriptional regulatory network prediction revealed that candidate ShRZFP genes may be regulated by transcription factors (TFs) including WRKY, AP2/ERF, TCP and DBB. qRT-PCR validation showed these 6 candidate ShRZFP genes were significantly responsive to key tillering-related phytohormones, suggesting their putative involvement in the negative regulation of sugarcane tillering. CONCLUSION: This study is the first systematic analysis of the ShRZFP gene family in sugarcane, which fills the research gap of this gene family in sugarcane, and provides valuable candidate genes and a preliminary theoretical basis for molecular improvement of sugarcane tillering traits.