Genome-Wide Identification of 13 miR5200 Loci in Wheat and Investigation of Their Regulatory Roles Under Stress

miR5200 is miRNA unique to Poaceae plants. Induced under short-day conditions, it modulates flowering time by regulating the florigen FT gene expression. However, to date, the genetic locus responsible for mature miR5200 formation remains experimentally unvalidated, and its biological function in abiotic stress responses remains unknown. This has hindered systematic elucidation of miR5200's physiological role and molecular mechanisms.

This study utilized wheat as the research material. First, through bioinformatics analysis at the genomic level, 13 potential candidate tae-miR5200 gene loci were screened. Subsequently, the authenticity of these gene loci was systematically validated by combining tobacco transient transfection-based GUS staining assay and quantitative real-time PCR (qRT-PCR) to detect expression levels. Building upon this foundation, the expression patterns of tae-miR5200 under abiotic stresses such as low temperature, drought, and salinity, as well as SA, ABA, IAA, GA₃, and MeJA treatments, were further investigated.

Experimental validation confirmed that 7 out of 13 potential gene loci are authentic and functional, and tae-miR5200 exhibited specific expression changes under different types of abiotic stress.

This study confirms the authenticity of tae-miR5200 gene loci, effectively eliminating interference from bioinformatics-predicted false-positive loci in subsequent functional studies. It provides an experimental foundation for further investigation into the molecular mechanisms of tae-miR5200 in wheat responses to abiotic stress.