Genome Survey Sequencing of Indigofera pseudotinctoria and Identification of Its SSR Markers

Background: Indigofera pseudotinctoria, a traditional Chinese forage and medicine widely used in East Asia, holds significant economic and agricultural value. Despite this, genomic information regarding I. pseudotinctoria remains conspicuously lacking. Methods: In this study, we utilized genome survey sequencing to elucidate the complete genome sequence of this species. Results: The genome size of I. pseudotinctoria to be around 637–920 Mb with a heterozygosity rate of 0.98% and a repeat rate of 66.3%. A total of 240,659 simple sequence repeat (SSR) markers were predicted in the genome of I. pseudotinctoria. Substantial differences were observed among nucleotide repeat types, for instance, mononucleotide repeats were found to be predominant (62.47%), whereas pentanucleotide repeats were notably scarce (0.24%). Furthermore, among dinucleotide and trinucleotide repeats, sequence motifs AT/AT (66.57%) and AAT/ATT (54.15%) were found to be particularly abundant. Among the identified unigenes, 58,790 exhibited alignment with known genes in established databases, including 33,218 genes within the Gene Ontology (GO) database and 10,893 genes in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Conclusions: This study marks the first attempt to both sequence and delineate the genomic landscape of I. pseudotinctoria. Importantly, it will serve as a foundational reference for subsequent comprehensive genome-wide deep sequencing and the development of SSR molecular markers within the scope of I. pseudotinctoria research.