Inflorescence degeneration in Areca catechu L. is characterized by growth arrest, tissue shrinkage and browning, ultimately compromising functional inflorescence formation and yield stability. To investigate its developmental window and regulatory basis, inflorescences from different leaf positions at the full-bloom stage were analyzed using anatomical observation, morphological measurements, carbohydrate and hormone assays, and RNA-seq-based transcriptomic analysis with qRT-PCR validation. Inflorescence degeneration was mainly concentrated in axillary inflorescences at the third and fourth leaf positions (BY3 and BY4). Compared with adjacent normal inflorescences, degenerated inflorescences showed reduced sucrose, starch and trehalose contents, increased ABA, JA and MeJA levels, and decreased cZR levels. Transcriptomic analysis revealed clear separation between degenerated and normal inflorescences, and differentially expressed genes were enriched in starch and sucrose metabolism, plant hormone signal transduction and transcriptional regulation. Co-expression network analysis identified modules associated with the degeneration window and key physiological traits, highlighting six candidate hub genes: AcAHP2, AcTIFY4B, AcTPS9-2, AcHXK2, AcWRKY3 and AcMPK1. These findings suggest that inflorescence degeneration is closely associated with carbon metabolic imbalance, hormone network remodeling and co-expression network reprogramming within a specific developmental window, providing a basis for future mechanistic studies and control strategies.

Jasmonate ZIM-domain (JAZ) proteins play a pivotal role in mediating plant growth, development, and responses to both biotic and abiotic stresses. However, our knowledge about the JAZ family genes in Areca catechu remains limited. This study conducted a genome-wide screening and analysis of JAZ genes in A. catechu to investigate their biochemical characteristics, gene structure features, phylogenetic relationships, and expression profiles in different organs. A total of 14 JAZ genes (AcJAZs) were detected in the A. catechu genome, all containing an N-terminal TIFY domain and a C-terminal Jas domain. Phylogenetic analysis categorized these AcJAZs into five subfamilies according to their similarities in protein sequences. Quantitative real-time reverse transcription PCR (qRT-PCR) experiments demonstrated the ample expression specificity of these AcJAZ genes across different organs and flower development stages. More importantly, most AcJAZ genes are expressed significantly higher in blooming male flowers than female flowers, suggesting that they may participate in regulating the difference between male and female flowers of A. catechu. This study elucidates the genomic features and functions of JAZ genes in A. catechu, providing new insights into the mechanisms underlying the development and differentiation of unisexual flowers in A. catechu.