Genome-wide analysis and expression characteristics of Small Auxin-up RNAs genes in flax (Linum usitatissimum L.)

Plant auxin is crucial in regulating many aspects of plant growth and development. Small Auxin-up RNAs (SAURs) genes act as the main early auxin response genes and are involved in regulating plant growth and development. Flax is a well-known fiber and oil crop; thus, our study provided a systematic bioinformatics analysis of the SAUR family in flax, including basic parameters, gene structure, chromosomal location, phylogenetic analysis, and cis-acting element analysis. Based on genomic information, 86 LusSAUR genes were identified and separated into eight groups. The gene structure analysis revealed that only two LusSAUR genes have introns. The cis-acting elements related to hormones and stress were abundant in the promoter region of LusSAUR members. Based on the gene expression oligo microarray, LusSAUR genes had tissue-specific expression characteristics in eight different tissues. Quantitative real-time PCR analysis indicated that 10 selected LusSAUR genes could be quickly upregulated following treatment with IAA. The 10 genes displayed distinctive expression levels under hormone treatment (MeJA, ABA, SA) and abiotic stress (PEG, NaCl, CdCl2). This study provides a foundation for further investigations for functional analysis of LusSAURs in flax. Furthermore, it will provide useful insights for further research into the molecular mechanism of regulating hormones and environmental signals in flax growth and development.