Genome-Wide Identification and Expression Analysis of the AS2/LOB Transcription Factor Family in Asparagus...

AS2/LOB transcription factors are central regulators of plant organ development and stress responses, yet their characteristics in the monocot crop Asparagus officinalis remain uncharacterized.

In this study, we leveraged the A. officinalis genome to perform a genome-wide identification and comprehensive characterization of the AS2/LOB family. We identified 20 AoAS genes (AoAS01-AoAS20) and analyzed their physicochemical properties, chromosomal localization, conserved domains and motifs, phylogenetic relationships, gene structures, cis-regulatory elements, duplication history, syntenic relationships, protein-protein interaction networks and expression profiles.

Phylogenetic analysis divided the AoAS proteins into two major clades (Class I and Class II), while chromosomal mapping revealed their uneven distribution across eight chromosomes. Analysis of publicly available RNA-seq data showed that 14 AoAS genes exhibit dynamic expression across four developmental stages of the stem (10, 25, 40 and 60 cm), with AoAS11 and AoAS14 consistently displaying high transcript levels. Under drought stress, 12 AoAS genes showed significant transcriptional changes, with AoAS04 and AoAS14 exhibiting the most pronounced expression responses.

Together, these results provide a genome-wide portrait of the AS2/LOB family in asparagus, reveal their potential roles in development and drought response, nominate candidate genes for breeding stress-tolerant cultivars, and offer a useful benchmark for molecular breeding in economically important species including peony (Paeonia lactiflora).