Genome-wide identification and characterization of the FLA gene family in sorghum under salt-alkali stress

Fasciclin-like arabinogalactan proteins (FLAs) are crucial for plant growth and development. Utilizing whole genome data, this study delineated the number of genes, gene structure, chromosomal localization, protein structure, evolutionary relationships, and Gene Ontology (GO) annotations of the FLA family in sorghum (Sorghum bicolor L.). In addition, FLA genes' expression in wild-type sorghum (P898012) under salt-alkali stress (SAS) was examined. We identified 26 FLA genes in sorghum. Phylogenetic analysis divided these genes into five subgroups, where members within the same subgroup exhibited extremely similar, though not identical, gene structures. A collinearity analysis of the sorghum FLA genes revealed that SbFLA19 does not share a homologous relationship with those in Zea and Arabidopsis, suggesting its uniqueness to sorghum. Promoter element analysis indicated that the FLA genes contain various response elements associated with abiotic stress. GO annotations demonstrated that most FLA proteins are primarily located on the plasma membrane and are involved in diverse biological processes. Transcriptomic data and qRT-PCR analysis under SAS revealed that members of the SbFLA family responded to stress at different times. These findings provide valuable references for breeding sorghum varieties tolerant to salt-alkali conditions.