Rice LSD1-like Genes: Genome-Wide Characterization and Evidence Linking OsLSD3 to Plant Height

LSD1-like zinc-finger proteins participate in programmed cell death, redox homeostasis, and stress responses in plants, but their functional diversification and contributions to agronomic variation in rice remain poorly defined. This study aimed to characterize the rice LSD1-like gene family and evaluate the potential agronomic roles of selected members, with particular emphasis on OsLSD3. Genome-wide analyses were integrated with OsLSD3 natural variation and haplotype analyses in 4666 rice accessions, CRISPR/Cas9 mutant phenotyping in the ZH11 background, and subcellular localization assays. Seven LSD1-like genes were identified and showed substantial divergence in protein architecture, gene organization, promoter cis-element profiles, and tissue- and stress-responsive expression. OsLSD3 formed six population-structured haplotypes, and two common Japonica haplotypes differed significantly in plant height. Consistently, two independent oslsd3 mutant lines were taller than the wild type, whereas additional changes in grain-related traits were line-specific. OsLSD2 and OsLSD3 localized mainly to the nucleus, while OsLSD4 was predominantly nuclear with weak cytoplasmic localization. These results identify OsLSD3 as the strongest candidate among the examined members for further investigation of plant height- and grain-related traits, while OsLSD2 and OsLSD4 represent additional candidates for grain-trait regulation. Further validation using additional alleles and environments is required.