Construction Of High-Resolution Genetic Map And Comparative Genomic Analysis In Miscanthus

Miscanthus(Poaceae,Andropogoneae,Saccharinae)is a genus of temperate perennial C4 grasses whose high biomass production makes it,along with its close relatives sugarcane and sorghum,attractive as a biofuel feedstock.The base chromosome number of Miscanthus(x = 19)is different from that of other Saccharinae and approximately twice that of the related Sorghum bicolor(x = 10),showing that largescale duplications may have occurred in recent ancestors of Miscanthus.Because of the complexity of the Miscanthus genome and the complications of self-incompatibility,a complete genetic map with a high density of markers and complete chromosome coverage has not yet been developed.This complete and high resolution composite linkage map will serve as a useful resource for novel QTL discoveries,and enable informed deployment of the wealth of existing genomics resources of other species to the improvement of Miscanthus as a high biomass energy crop.In addition,it has utility as a reference for genome sequence assembly for the whole genome sequencing of the Miscanthus genus in the near future.In this study,genetic linkage map was constructed from the hybrid between M.sacchariflorus and M.floriduluswere,sequencing was used with the Illumina platform and RAD(Restriction-site associated DNA)sequencing.We aimed to construct a linkage map of the genus Miscanthus and then use it to perform comparative genomics with the Sorghum genome to understand the evolution in Miscanthus.The main results were as follows:1.The composite linkage map comprised 2,532 markers(Table 1)spanning 4458 cM on 19 linkages with an average distance between markers of 1.76 cM(figure 1).The lengths of linkage groups ranged from 122 cM(LG4)to 371(LG13).The linkage makers varied among the linkage group from 80 markers(LG19)to 197 makers(LG14).2.The comparative results revealed that each pair of the 19 M.sinensis linkages aligned to one sorghum chromosome,except for LG8,which mapped to two sorghum chromosomes(4 and 7),presumably due to a chromosome fusion event prior to genome duplication.The data also revealed several other chromosome rearrangements relative to sorghum,including two paracentric inversions of sorghum syntenic chromosome 2 in LG3 and chromosome 6 in LG12 of Miscanthus.