Dysfunction of an Anaphase-Promoting Complex Subunit 8 Homolog Leads to Super-Short Petioles and Enlarged Petiole Angles in Soybean.

Plant height, petiole length, and the angle of the leaf petiole and branch angles are crucial traits determining plant architecture and yield in soybean ( L.). Here, we characterized a soybean mutant with super-short petioles (SSP) and enlarged petiole angles (named ) through phenotypic observation, anatomical structure analysis, and bulk sequencing analysis. To identify the gene responsible for the mutant phenotype, we established a pipeline involving bulk sequencing, variant calling, functional annotation by SnpEFF (v4.0e) software, and Integrative Genomics Viewer analysis, and we initially identified , encoding a homolog of Anaphase-promoting complex subunit 8 (APC8). Another mutant, , with a large deletion of many genes including , has super-short petioles and an enlarged petiole angle, similar to the phenotype. Characterization of the mutant together with quantitative trait locus mapping and allelic variation analysis confirmed as the gene involved in the phenotype. In , a 4 bp deletion in leads to a 380 aa truncated protein due to a premature stop codon. The dysfunction or absence of caused severe defects in morphology, anatomical structure, and physiological traits. Transcriptome analysis and weighted gene co-expression network analysis revealed multiple pathways likely involved in these phenotypes, including ubiquitin-mediated proteolysis and gibberellin-mediated pathways. Our results demonstrate that dysfunction of leads to diverse functional consequences in different tissues, indicating that this APC8 homolog plays key roles in cell differentiation and elongation in a tissue-specific manner. Deciphering the molecular control of petiole length and angle enriches our knowledge of the molecular network regulating plant architecture in soybean and should facilitate the breeding of high-yielding soybean cultivars with compact plant architecture.