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Researchers from the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, led by Dr. CAO Xiaofeng, have advanced the genetic understanding of Leymus chinensis (sheepgrass), a crucial grass species in the Eurasian steppe. By employing a tailored genome editing system, they have enhanced biomass-related characteristics in sheepgrass, offering a deeper insight into its genomics.
L. chinensis is renowned for its resilient rhizomes and boasts attributes such as frost, drought, and salt tolerance, coupled with effective soil stabilization. Notably, it offers substantial ecological and economic benefits as a forage due to its superior nutritional content and taste. Yet, its vast genome size and elevated heterozygosity have made it a challenging species to study.
A Closer Look at the Study
For this research, the team chose L. chinensis Lc6-5, a sheepgrass variety from Northeast China's grasslands known for its strong rhizomes. They employed advanced sequencing and assembly techniques for genome assembly. The result was a genome approximately eight Gb in size, with a contig N50 exceeding 300 Mb and repetitive sequences making up 87.76% of the genome.
Given the genome's notable heterozygosity, the scientists also carried out a haplotype-level assembly. This information will be essential for subsequent genomic studies.
Editing for Enhanced Growth
Taking their work further, the team applied their tailored CRISPR/Cas9 system to Lc6-5, targeting the microRNA MIR528. This modification led to a substantial increase in the number of tillers and the plant's growth rate.
The meticulously assembled sheepgrass genome, when paired with the team's genome editing system, not only improves L. chinensis's biomass but also sets a foundation for its fast genetic enhancement and genome-centric breeding.
The findings of this study were recently published in PNAS on Oct. 24.