Project description:Switchgrass (Panicum virgatum) has been developed into a model lignocellulosic bioenergy crop. Downregulation of caffeic acid O-methyltransferase (COMT), a key enzyme in lignin biosynthesis, led to altered lignification and increased biofuel yield in switchgrass. Methylenetetrahydrofolate reductase (MTHFR) mediated C1 metabolism provides methyl units consumed by COMT. It was predicted that co-silencing of MTHFR and COMT would have a more significant impact on lignification than either of the single genes. However, our results showed that strong downregulation of MTHFR in a COMT-deficient background led to altered plant growth and development, but no significant change in lignin content or composition was found when compared with COMT plants. Another unexpected finding is that the double MTHFR/COMT downregulated plants showed a novel lesion-mimic leaf phenotype. Molecular analyses revealed that the lesion-mimic phenotype was caused by the synergistic effect of MTHFR and COMT genes, with MTHFR playing a predominant role. Microarray analysis showed significant induction of genes involved in oxidative and defenserelated processes. The results demonstrated the lack of additive effects of MTHFR and COMT on lignification. Furthermore, this research revealed an unexpected role of the two genes in the modulation of lesion-mimic cell death as well as their synergetic effects on agronomic performance.
Project description:Sequencing the metatranscriptome can provide information about the response of organisms to varying environmental conditions. We present a methodology for obtaining random whole-community mRNA from a complex microbial assemblage using Pyrosequencing. The metatranscriptome had, with minimum contamination by ribosomal RNA, significant coverage of abundant transcripts, and included significantly more potentially novel proteins than in the metagenome. Keywords: metatranscriptome, mesocosm, ocean acidification
Project description:The rumen harbors a complex mixture of archaea, bacteria, protozoa and fungi that efficiently breakdown plant biomass and its complex dietary carbohydrates into soluble sugars that can be fermented and subsequently converted into metabolites and nutrients utilized by the host animal. While rumen bacteria populations have been well documented, only a fraction of the rumen eukarya are taxonomically and functionally characterized, despite the recognition that they contribute to the cellulolytic phenotype of the rumen fauna. To investigate how anaerobic fungi actively engage in digestion of recalcitrant fiber that is resistant to the initial stages of rumination, we resolved genome-centric metaproteome and metatranscriptome datasets generated from switchgrass samples incubated in nylon bags within the rumen of cannulated dairy cows for 48 hours.