Exons display significant length variability, with those measuring less than 51 nucleotides (nt) categorized as microexons. This database specifically targets ultra-short microexons, characterized as those ranging from 1 to 15 nt.

Using large-scale RNA-seq datasets consisting of 990 samples from diverse tissues, developmental stages, and environmental conditions, we conducted a genome-wide identification of microexons in 10 representative plant species. This analysis discovered 2,398 high-confidence internal microexons.

Leveraging these data, we developed a microexon prediction tool and applied it to 132 plant genomes , identifying a total of 20,224 microexons . This database provides comprehensive information on these microexons to facilitate further research.