Date Published: February 1, 2019
Publisher: Public Library of Science
Author(s): Sai Yang, Shuai Xue, Weiwei Kang, Zhuxi Qian, Zili Yi, Tzen-Yuh Chiang.
Miscanthus lutarioriparius is a native perennial Miscanthus species of China, which is currently used as raw material of papermaking and bioenergy crop. It also has been considered as a promising eco-bioindustrial plant, which can offer raw material and gene for the biomass industry. However, lack of germplasm resources and genetic diversity information of M. lutarioriparius have become the bottleneck that prevents the stable and further development of the biomass industry. In the present study, genetic diversity of 153 M. lutarioriparius individuals nine populations was studied using 27 Start Codon Targeted (SCoT) markers. High polymorphic bands (97.67%), polymorphic information content (0.26) and allele number (1.88) showed SCoT as a reliable marker system for genetic analysis in M. lutarioriparius. At the species, the percentage of polymorphic loci [PPL] was 97.2%, Nei’s gene diversity [H] was 0.36, Shannon index [I] was 0.54 and Expected Heterozygosity [He] was 0.56. Genetic variation within populations (84.91%) was higher than among populations (15.09%) based on analysis of molecular variance (AMOVA). Moderate level of genetic differentiation was found in M. lutarioriparius populations (Fst = 0.15), which is further confirmed by STRUCTURE, principal coordinates analysis (PCoA) and an unweighted pair group method with arithmetic mean (UPGMA) analysis that could reveal a clear separation between groups of the north and south of Yangtze River. The gene flow of the populations within the respective south and north of Yangtze River area was higher, but lower between the areas. There was no obvious correlation between genetic distance and geographic distance. The breeding systems, geographical isolation and fragmented habitat of M. lutarioriparius may be due to the high level of genetic diversity, moderate genetic differentiation, and the population, structure. The study further suggests some measure for conservation of genetic resources and provides the genetic basis for improving the efficiency of breeding based on the results of diversity analysis.
Miscanthus spp. is a perennial herbaceous grass belonging to the Poaceae  with origins in East and Southeast Asia. China is the distribution center of the world’s Miscanthus resources, and Miscanthus lutarioriparius is native to China among all Miscanthus species [1–3]. Miscanthus has a strong ability to adapt to different habitats owing to rich morphological and genetic diversity [2–5]. It is considered one of the most promising second-generation energy crops with high C4 photosynthetic efficiency  high and stable yield potential [7,8], fast growth, low-nutrient requirement , high water-use efficiency [10,11], high disease resistance , and high cellulose content . Additionally, Miscanthus can also provide raw materials for biorefineries to produce various chemicals, fuel, and biomaterials [14–17] and is beneficial for reducing the risk of soil erosion  and increasing soil carbon content and biodiversity . Therefore, identification of Miscanthus varieties with high biomass yield and good energy-related quality is desirable.
In conclusion, the SCoT marker system provides a highly efficient, reproducible and powerful tool for studying the genetic diversity and population structure of M. lutarioriparius. The results revealed that high genetic diversity and gene flow were detected at species level, which were attributed to its breeding system, large distribution area and anthropogenic movement of plant material. In addition, moderate genetic differentiation was found among populations, which was supported by habitat fragmentation and geographical isolation. Nine populations can be divided into two main groups by STRUCTURE analysis, PCoA and UPGMA, with the Yangtze River as a natural boundary between the two groups. All M. lutarioriparius accessions could be divided into two groups, with 92 accessions in Cluster A and 61 accessions in Cluster B. Lastly, we offered scientific measures for M. lutarioriparius protection. Thus, these results should help for selecting parents in hybridized breeding to exploiting new Miscanthus species and for further utilization in biomass energy and conservation.