Calviño Torterolo, Martĺn. Comparative genomics of the stem transcriptome from grain and sweet sorghum. Retrieved from https://doi.org/doi:10.7282/T3K35S35
DescriptionThe current dissertation relates to comparative genomics of grain and sweet sorghum, in particular, to their stem’s transcriptome at the time of flowering, when soluble sugars accumulate more abundantly in the sweet sorghum cultivar Rio than in the grain sorghum cultivar BTx623. The accumulation of soluble sugars in the stem of sorghum is a valuable agronomic trait because their fermentation into ethanol is currently being used as source of biofuel. High soluble sugar content in stems is a trait also present in the closely related grass sugarcane. Thus, it is reasonable to assume that sweet sorghum and sugarcane may use the same gene products that leads to high soluble sugar content is stems. My dissertation consists of five chapters, the results of which are five publications as first author. In Chapter 1 I summarized the current status of sweet sorghum genomics and highlighted future research directions. My scientific contribution to the field was also mentioned. In Chapters 2 and 3 I described the first characterization of the stem’s transcriptome from grain and sweet sorghum cultivars using sugarcane Affymetrix arrays, and the use of this transcriptome data to develop molecular markers based on the differences in hybridization intensity from grain and sweet sorghum RNAs to the arrays. In Chapter 4, I described the first characterization of the small RNA component of the stem from grain sorghum BTx623 and sweet sorghum Rio cultivars, and from F2 plants derived from their cross that segregated for sugar content and flowering time. I was able to identify the microRNA family miR169, whose expression co-segregated with sugar content in stems. I also discovered nine new microRNAs in the sorghum genome. In Chapter 5 I described the genomic comparison of MIR169 gene clusters among five different grasses and identified five new MIR169 gene copies in the sorghum genome.