Chromosome-scale genome assembly of Astragalus membranaceus using PacBio and Hi-C technologies

Area of Science:

• Genomics
• Plant Biology
• Medicinal Chemistry

Background:

• Astragalus membranaceus (Fisch.) Bge (AM) is a significant medicinal herb in the Leguminosae family, utilized for Astragali Radix.
• Understanding the genetic makeup of AM is crucial for its medicinal applications and breeding programs.

Purpose of the Study:

• To generate a chromosome-scale genome assembly of Astragalus membranaceus.
• To provide a high-quality genomic resource for molecular biology and functional studies of AM and other Leguminosae species.

Main Methods:

• Chromosome-scale genome assembly using Hi-C technology.
• Genome size estimation, contig N50 calculation, and assembly anchoring to pseudochromosomes.
• Assessment of assembly completeness using BUSCO and analysis of repetitive sequences.

Main Results:

• A 1.43 Gb genome assembly with a contig N50 of 1.67 Mb, with 98.16% anchored to 9 pseudochromosomes.
• Assembly completeness estimated at 97.27% with LAI of 16.22 and QV of 48.58.
• Annotation identified 29,914 protein-coding genes, including 73 in the flavonoid pathway and 2,048 transcription factors, with 67.98% repetitive sequences.

Conclusions:

• A high-quality chromosome-scale genome assembly for Astragalus membranaceus has been successfully generated.
• This genomic resource significantly enhances the potential for future functional genomic studies in AM and the broader Leguminosae family.
• The identified genes provide a foundation for understanding the biosynthesis of important compounds like flavonoids in AM.