Screen of Genes Linked to High-Sugar Content in Stems by Comparative Genomics

One of the great advantages of the fully sequenced rice genome is to serve as a reference for other cereal genomes in particular for identifying genes linked to unique traits. A trait of great interest is reduced lignocellulose in the stem of related species in favor of fermentable sugars as a source of biofuels. While sugarcane is one of the most efficient biofuel crops, little is known about the underlying gene repertoire involved in it. Here, we take advantage of the natural variation of sweet and grain sorghum to uncover genes that are conserved in rice, sorghum, and sugarcane but differently expressed in sweet versus grain sorghum by using a microarray platform and the syntenous alignment of rice and sorghum genomic regions containing these genes. Indeed, enzymes involved in carbohydrate accumulation and those that reduce lignocellulose can be identified.