Study was conducted to evaluate in vitro digestibility of native warm-season grasses. Three grasses were used: big bluestem (Andropogon gerardii Vitman), little bluestem (Schizachyrium scoparium Nash), and indiangrass (Sorghastrum nutans Nash). There were no differences in NDF, ADF, FAT and OM of the three grass species. However, DM, hemicellulose and CP were slightly different in the three grass species. Also, the frequency nested in cutting effects was determined. In vitro dry matter disappearance of big bluestem, little bluestem and indiangrass was evaluated to determine rate of disappearance. The 100 % indiangrass revealed the greatest rate of disappearance for IVDMD and 100 % little bluestem grass the least, respectively. However, that of other proportion mixtures of treatments and 100 % big bluestem grass were in between. There were no differences in in vitro neutral detergent fiber disappearances among treatments.

As características físico-químicas da parede celular constituem um grande gargalo na obtenção dos açúcares fermentáveis a partir dos polissacarídeos de parede celular presentes na biomassa, fato conhecido como recalcitrância da biomassa vegetal. A utilização da biomassa na produção de biocombustíveis requer um melhor entendimento sobre os mecanismos que permeiam os processos de deposição de parede celular e metabolismo de lignina. Nesse contexto, a maior parte do conhecimento foi gerado em espécies eudicotiledôneas, havendo uma significativa lacuna para gramíneas, apesar do seu grande potencial para acúmulo de biomassa. Portanto, há uma necessidade de se estabelecer ferramentas-modelos que permitam elucidar características exclusivas da parede celular secundária de gramíneas C4, cujo conhecimento não pode ser extrapolado a partir de eudicotiledôneas. O presente trabalho propôs estabelecer um sistema de células em suspensão como ferramenta-modelo em estudos sobre parede celular secundária em gramíneas C4. Para tal, três espécies foram inclusas: Sorghum bicolor, Setaria viridis e cana-de-açúcar. Devido às características recalcitrantes do sorgo, apenas as suspensões celulares de S. viridis e cana-de-açúcar foram estabelecidas. Subsequentemente, estas culturas foram utilizadas na tentativa de se desenvolver duas aplicações para o estudo de parede secundária: i) culturas xilogênicas, em que as células em suspensão são induzidas a se transdiferenciar em elementos traqueais; e ii) sistema de protoplastos para ensaios de transativação para testar o potencial papel de fatores de transcrição na regulação transcricional da deposição de parede celular. Somente as culturas de cana-de-açúcar responderam aos tratamentos testados para indução da transdiferenciação de elementos traqueais, baseados em protocolos estabelecidos para outras gramíneas. Análises de expressão gênica por RT-qPCR foram utilizadas para caracterizar a variação da expressão de genes-alvo durante este processo. Ademais, as paredes celulares das células em suspensão de cana-de-açúcar foram digeridas com um coquetel de hidrolases para a produção de protoplastos. A cultura de células em suspensão de cana-de-açúcar e suas aplicações aqui estabelecidas poderão ser utilizadas na elucidação de aspectos únicos do processo de deposição de parede celular secundária em gramíneas C4 / The physicochemical features of the cell wall represent a major bottleneck for the processing of cell wall polysaccharides present in biomass into fermentable sugars, a fact known as plant biomass recalcitrance. Biofuels production from biomass requires a better understanding on the molecular mechanisms underlying secondary cell wall deposition and lignin metabolism. In this context, most of the current knowledge has been generated in eudicots species, whereas significantly less is known for grasses, despite of their great potential for biomass accumulation. Therefore, the development of tools that allow the discovery of specific aspects of C4 grasses secondary cell walls is of great interest, because this knowledge cannot be extrapolated from data generated for eudicots. In the present work, we aimed to develop suspension cell cultures as a tool for the study of secondary cell wall metabolism in C4 grasses. For this purpose, three species were employed: Sorghum bicolor, Setaria viridis and sugarcane. Because of the recalcitrant nature of sorghum, only suspensions cells of S. viridis and sugarcane were successfully established. Subsequently, these cultures were used in an attempt to develop two applications to study secondary cell walls: i) xylogenic cultures, in which the suspension cells are induced to transdifferentiate into tracheary elements; and ii) a protoplast system to be used in transactivation assays to test the potential role of transcriptional factors in the regulation of secondary wall deposition. Only the suspension cultures of sugarcane showed a positive response to the tested treatments for the induction of tracheary elements formation, which were based on modifications of previous protocols established for other grasses. Gene expression analysis by RT-qPCR was used to characterize the variation of the expression of target genes during this process. Moreover, the cell walls of sugarcane suspension cells were digested with a cocktail of hydrolases to produce protoplasts, which were used in transactivation assays between transcriptional factors known to be involved in secondary cell wall deposition and their putative target genes, as a proof-of-concept. The sugarcane suspension cells and their applications established in this work might be used to further elucidate unique aspects of secondary cell wall deposition in C4 grasses

Temperate Midwestern oak savannas are considered imperiled ecosystems with < 1 % remaining since the time of European settlement and are identified as critical areas for preservation. Restoration of Midwestern oak savannas is challenging due to the lack of accurate historical data, few intact remnants remaining to study, and lack of restoration ecology studies. A plant trait-based approach was used to evaluate the ability of six C3 and three C4 native bunchgrasses to restore functionality to a remnant savanna–woodland of the Bluegrass Region of Kentucky. The response and effect framework was used to assess the response of the nine native grasses according to the habitat filters of interannual precipitation, inter- vs. intra-specific competition, and simulated grazing. The effect traits associated with plant-soil nitrogen and carbon cycling were also assessed. The response traits of interannual competition and inter- vs. intra-specific competition along with the effect traits plant-soil nitrogen and carbon cycling were measured in a monoculture experiment conducted at Griffith Woods WMA. The simulated grazing or clipping experiment was conducted over three months in a heated greenhouse experiment. Four of the C3 species were of the genus Elymus which had significant differences in life history traits compared to the other species and made them particularly well adapted to the Bluegrass Savanna-Woodland. The Elymus species were not well adapted to the most intense clipping treatment. For the other two C3 species, C. latifolium would be a better competitor than D. clandestinum under normal conditions. D. clandestinum had the most number of plastic traits and was the only species to exhibit all three grazing strategies. Comparing the C4 species, T. flavus and P. anceps grew well in the monoculture but A. virginicus did not. The life history traits of A. virginicus does not make this species a good candidate for restoration at this site. The three C4 species were well adapted to clipping. The results of this study suggest that the C3 species, particularly the Elymus, are well adapted to the eutrophic mesic conditions of the Bluegrass Savanna-Woodland, and that the C4 species are better adapted to disturbance.

As características físico-químicas da parede celular constituem um grande gargalo na obtenção dos açúcares fermentáveis a partir dos polissacarídeos de parede celular presentes na biomassa, fato conhecido como recalcitrância da biomassa vegetal. A utilização da biomassa na produção de biocombustíveis requer um melhor entendimento sobre os mecanismos que permeiam os processos de deposição de parede celular e metabolismo de lignina. Nesse contexto, a maior parte do conhecimento foi gerado em espécies eudicotiledôneas, havendo uma significativa lacuna para gramíneas, apesar do seu grande potencial para acúmulo de biomassa. Portanto, há uma necessidade de se estabelecer ferramentas-modelos que permitam elucidar características exclusivas da parede celular secundária de gramíneas C4, cujo conhecimento não pode ser extrapolado a partir de eudicotiledôneas. O presente trabalho propôs estabelecer um sistema de células em suspensão como ferramenta-modelo em estudos sobre parede celular secundária em gramíneas C4. Para tal, três espécies foram inclusas: Sorghum bicolor, Setaria viridis e cana-de-açúcar. Devido às características recalcitrantes do sorgo, apenas as suspensões celulares de S. viridis e cana-de-açúcar foram estabelecidas. Subsequentemente, estas culturas foram utilizadas na tentativa de se desenvolver duas aplicações para o estudo de parede secundária: i) culturas xilogênicas, em que as células em suspensão são induzidas a se transdiferenciar em elementos traqueais; e ii) sistema de protoplastos para ensaios de transativação para testar o potencial papel de fatores de transcrição na regulação transcricional da deposição de parede celular. Somente as culturas de cana-de-açúcar responderam aos tratamentos testados para indução da transdiferenciação de elementos traqueais, baseados em protocolos estabelecidos para outras gramíneas. Análises de expressão gênica por RT-qPCR foram utilizadas para caracterizar a variação da expressão de genes-alvo durante este processo. Ademais, as paredes celulares das células em suspensão de cana-de-açúcar foram digeridas com um coquetel de hidrolases para a produção de protoplastos. A cultura de células em suspensão de cana-de-açúcar e suas aplicações aqui estabelecidas poderão ser utilizadas na elucidação de aspectos únicos do processo de deposição de parede celular secundária em gramíneas C4 / The physicochemical features of the cell wall represent a major bottleneck for the processing of cell wall polysaccharides present in biomass into fermentable sugars, a fact known as plant biomass recalcitrance. Biofuels production from biomass requires a better understanding on the molecular mechanisms underlying secondary cell wall deposition and lignin metabolism. In this context, most of the current knowledge has been generated in eudicots species, whereas significantly less is known for grasses, despite of their great potential for biomass accumulation. Therefore, the development of tools that allow the discovery of specific aspects of C4 grasses secondary cell walls is of great interest, because this knowledge cannot be extrapolated from data generated for eudicots. In the present work, we aimed to develop suspension cell cultures as a tool for the study of secondary cell wall metabolism in C4 grasses. For this purpose, three species were employed: Sorghum bicolor, Setaria viridis and sugarcane. Because of the recalcitrant nature of sorghum, only suspensions cells of S. viridis and sugarcane were successfully established. Subsequently, these cultures were used in an attempt to develop two applications to study secondary cell walls: i) xylogenic cultures, in which the suspension cells are induced to transdifferentiate into tracheary elements; and ii) a protoplast system to be used in transactivation assays to test the potential role of transcriptional factors in the regulation of secondary wall deposition. Only the suspension cultures of sugarcane showed a positive response to the tested treatments for the induction of tracheary elements formation, which were based on modifications of previous protocols established for other grasses. Gene expression analysis by RT-qPCR was used to characterize the variation of the expression of target genes during this process. Moreover, the cell walls of sugarcane suspension cells were digested with a cocktail of hydrolases to produce protoplasts, which were used in transactivation assays between transcriptional factors known to be involved in secondary cell wall deposition and their putative target genes, as a proof-of-concept. The sugarcane suspension cells and their applications established in this work might be used to further elucidate unique aspects of secondary cell wall deposition in C4 grasses