Comparative Genome Relationship Between Agrostis Stolonifera and Brachypodium Distachyon.

Understanding of grass genome structure and evolution has been advanced through comparative genomics research during the last couple of decades. Rice (Ehrhartoideae) has been considered the most attractive system for comparative grass genomics due to its genome size and available genome sequences yet its value, as a model plant for temperate cereals, forage, and turfgrass is in question. Most cool-season forage and turf grasses belonging to the Pooideae subfamily within the grass family are underrepresented species. Among them, creeping bentgrass (Agrostis stolonifera, allotetraploid 2n=4x=28) is one of the most important species widely used on golf courses due to its low mowing tolerance and aggressive stoloniferous growth habit. Recently domesticated, polyploid creeping bentgrass can add to the understanding of grass evolution and domestication. One approach to accomplish a better understanding of evolution and speciation of this species is the use of comparative genomics. The whole genome of Brachypodium distachyon in the Pooideae subfamily was recently sequenced and is proposed as a model plant for these studies. Comparative analysis of 8,470 publically available A. stolonifera EST (AgEST) sequences and 163 physically mapped EST-RFLP markers with Brachypodium genome was performed. As many as 856 AgEST were orthologous to the Brachypodium genome and 59% of the mapped EST-RFLP showed synteny between Brachypodium chromosomes and Agrostis linkage groups. Insights from comparative genomics with Brachypodium will be useful for genetic improvement of Agrostis spp. and provide a better understanding of the evolution of the Pooideae subfamily species.