Genome-Wide Characterization and Analysis of the bHLH Transcription Factor Family in , an Annual Halophyte With Single-Cell C Anatomy.

Basic helix-loop-helix (bHLH) transcription factors play important roles in plant growth, development, metabolism, hormone signaling pathways, and responses to abiotic stresses. However, comprehensive genomic and functional analyses of genes have not yet been reported in desert euhalophytes. , an annual C halophyte without Kranz anatomy, presents high photosynthetic efficiency in harsh natural habitats and is an ideal plant for identifying transcription factors involved in stress resistance. In this study, 83 genes in were identified and categorized into 21 subfamilies based on conserved motifs, gene structures, and phylogenetic analysis. Functional annotation enrichment revealed that the majority of SabHLHs were enriched in Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways involved in the response to stress conditions, as transcription factors. A number of -acting elements related to plant hormones and stress responses were also predicted in the promoter regions of , which were confirmed by expression analysis under various abiotic stress conditions (NaCl, mannitol, low temperature, ABA, GA, MeJA, and SA); most were involved in tolerance to drought and salinity. SabHLH169 (076) protein localized in the nucleus was involved in transcriptional activity, and gene expression could be affected by different light qualities. This study is the first comprehensive analysis of the gene family in These data will facilitate further characterization of their molecular functions in the adaptation of desert plants to abiotic stress.