Fall 2017 Biology Seminar Series: Daniel Kliebenstein
Daniel Acuna-Hurtado will be bringing in guest speaker Daniel Kliebenstein from UC Davis. His talk title is "The Evolution of Complexity; Specialized Metabolism Suggests There was Never Simplicity."
His abstract is as follows:
"A central goal of systems biology is modelling how complex systems are regulated. One of the most complex systems in multi-cellular biology is metabolism which exists as a large non-cell autonomous network involving reactions in diverse cell types connected by the vascular system. This multi-cellular aspect complicates the ability to take regulatory models built on cell-autonomous systems and apply them to understand how metabolic pathways are controlled. We apply diverse genomics tools from genome wide association mapping to high-throughput Yeast-1-hybrid (Y1H) to expand our understanding of how plant metabolism is regulated.
A fundamental question we are addressing using secondary metabolites is to ask how many transcription factors can actually influence a metabolic pathway. Using a high-throughput Y1H approach, we have found that the aliphatic glucosinolate pathway likely has >100 TFs that control the accumulation of glucosinolates at a level consistent with dramatic field fitness consequences. These TFs predict key biotic and abiotic influences expected to modulate glucosinolate content in a complex environment. These inputs were also found using a novel genome wide association mapping approach. This is generating unexpected observations about how “secondary” metabolic pathways are as central in regulatory networks as primary systems.
One conundrum of modern systems biology theory is that it is built on an unstable hierarchical regulatory model that requires stabilization. In engineering, this stabilization is usually provided by feed-back regulation coming from the actual output. We are directly testing if defense compounds, aliphatic glucosinolates, have unidentified regulatory roles. Work will be presented showing that the end products of this pathway are actually key regulators of core physiological and transcriptional processes and that the plant must have a complement of structurally specific glucosinolate sensors.
Finally, we are directly testing if the aliphatic glucosinolates and associated genetic variation is adaptive in the field using multi-year field trials. This analysis is showing that this pathway is adaptive in all environments tested but that the optimal alleles change from year to year and location to location. This suggests that there is a high level of fluctuating selection and little local adaptation. This actually establishes a system in which maintaining genetic variation is actually the most fit solution."
For disability-related accommodations, including dietary accommodations, please visit www.ada.umb.edu two weeks prior to the event.