Background: The NAC family constitutes one of the largest families of plant-specific transcription factors and plays crucial roles in fruit development, ripening, seed life, and stress responses. However, comprehensive characterization of NAC genes in Persea americana (avocado), an economically important horticultural crop, has been largely unexplored. Methods: We performed a genome-wide identification and systematic characterization of NAC transcription factor (TF) genes in P. americana using blastp analysis, phylogenetic reconstruction, expression profiling and weighted gene co-expression network analysis (WGCNA). Results: A total of 130 NAC genes (PaNACs) were identified and distributed across all 12 chromosomes. Phylogenetic analysis classified these PaNACs into eight distinct subfamilies. WGCNA identified 43 co-expression modules, with 68 PaNAC genes distributed across 24 modules associated with hormone signaling, cell wall modification, secondary metabolism, and fatty acid beta-oxidation. Among 48,785 developmental differentially expressed genes (DEGs), 70 PaNAC genes were differentially expressed, with PaNAC003 and PaNAC002 showing the strongest upregulation and PaNAC023 and PaNAC025 the strongest downregulation. Among 9488 ethylene-responsive DEGs, PaNAC041 was suppressed by ethylene and induced by 1-methylcyclopropene (1-MCP, a competitive inhibitor of ethylene perception), while PaNAC016, PaNAC085, and PaNAC086 showed the opposite pattern. Conclusions: These findings provide a genomic and transcriptional framework for future functional investigation of PaNAC genes and their potential relevance to avocado fruit development and postharvest ripening.

Background: Bauhiniavariegata is a plant with considerable application potential owing to its combined ornamental, edible, aromatic, and medicinal values. However, research on this species remains limited and superficial both domestically and internationally, and systematic investigation of floral volatile organic compounds (VOCs) is still lacking. Methods: Through integrated metabolome and transcriptome analyses. Results: This study first comprehensively characterizes the VOC composition, floral scent profile, key aroma components, and the molecular mechanisms underlying VOC variation during anthesis in floral buds and flowers of B. variegata. A total of 1214 volatile compounds were identified across buds and flowers, including 239 odor-active compounds and 35 differential odor-active compounds. Flavor statistics revealed that the floral scent profile of B. variegata is dominated by fruity, sweet, floral, green, woody, herbal, citrus, phenol, fresh, and spicy notes. Compared to floral buds, most differential odor-active compounds were markedly upregulated in flowers, including key floral aroma constituents such as phenylacetaldehyde, rose oxide, (Z)-β-ocimene, 2-methylbenzaldehyde, and melon heptenal. Conversely, (R)-(+)-citronellal, which possesses defensive functions, and the bitter-tasting compound 1-methyl-4-nitro-benzene were significantly downregulated in flowers, reflecting a shift from a defense-oriented mode at the bud stage to an attraction-oriented mode at anthesis. Upregulation of phenylalanine/histidine ammonia-lyase, acyl-CoA synthetase, and squalene synthetase genes and downregulation of copper amine oxidase, O-methyltransferase, and aldo–keto reductase genes synergistically promoted accumulation of floral aroma compounds such as phenylacetaldehyde and facilitated the floral transition. Conclusions: This study provides important data support for understanding the ecological interactions between B. variegata floral scent and its pollinators, as well as the molecular mechanisms governing floral scent formation. Furthermore, it contributes to the application of B. variegata in landscaping, edible flower utilization, and fragrance development.

Proline serves as a key osmoprotectant and signaling molecule in plants under abiotic stress. Arbuscular mycorrhizal fungi (AMF), which form symbiotic rela