Kiel Plant Center

KPC Mini Symposium April 2021

Apr 28, 2021 from 03:00 PM to 04:30 PM

This is an online event. For access details please email kielplantcenter@bot.uni-kiel.de

15:00
Welcome

Chair: Dr. Serhat Sezai Çiçek, Pharmaceutical Biology, Kiel University

15:10
Speaker: Dr. Sofia Filatova, Assistant Professor, Environmental archaeology group, Institute for prehistoric and protohistoric archaeology, Kiel University
Title: Cultivation and diversity of rye (Secale cereale L.) in Medieval and Early Modern Central Europe: Insights from historical plant material.

Rye (Secale cereale L.) is a secondary domesticate, considered to have originated as a weed in cultivated fields of wheat and barley during the Neolithic and to have acquired its domestication traits through Vavilovian mimicry. With the exception of early finds of domesticated rye in Neolithic and Bronze Age Anatolia, it only started to appear in significant amounts in the archaeological record of European settlements from the Iron Age onwards, thousands of years after it first developed traits of domestication. The long transition of rye from (tolerated) weed to cultivated crop has most likely contributed to the exceptionally high genetic diversity in landraces and modern varieties of rye. In the project “Genetic Variation in Ancestral Crops” we seek to explore the history of rye cultivation and diversification by combining archaeobotanical analyses and ancient DNA sequencing. Our material starting point are well-preserved harvests from medieval and Early Modern Wellerhölzer, which originate from half-timbered houses throughout Central Europe and have traditionally been used as insulation between floors. This contribution will focus on the first results of the analysis of plant remains from two Wellerhölzer from Germany. Based on a variety of characteristics of the plants extracted from the Wellerhölzer (e.g. growing heights, species composition, autecology) an insight is given into past weed ecology and cultivation practices of rye.

15:25: Questions

15:30
Speaker: Junior Professor Jennifer Selinski, Botanical Institute, Kiel University
Title: Maintenance of cytosolic redox homeostasis under adverse growth conditions

The redox state provides information on the metabolic status of a plant cell, which needs to be kept at steady state for optimal performance even under continuously changing environmental conditions and developmental requirements. Since major imbalances in the redox state can cause severe damage, plant cells possess different redox sensors such as proteins with reversibly oxidisable thiols which detect any deviation from redox homeostasis and activate poising mechanisms, thus avoiding the generation of excess reactive oxygen species (ROS). Malate dehydrogenases (MDHs) are present in various cell compartments and are involved in key metabolic pathways as well as protection. It is now well accepted that plants use malate valves (with MDH as key enzyme) to counterbalance metabolic imbalances and maintain redox-homeostasis in plant cells. While MDH isoforms of plastids, mitochondria and peroxisomes are well characterized, less is known about cytosolic MDHs. We could show recently that cytosolic MDH isoforms are differentially regulated on the post-translational level. Furthermore, localization studies under different redox conditions revealed that cytosolic MDHs translocate to the nucleus under oxidizing conditions linking energy metabolism to adaptive stress responses required for the maintenance of redox homeostasis. In this context, the possible role of cytosolic MDHs in the nucleus will be discussed.

15.45: Questions

15:50
Speaker: Dr. Elisabeth Kaltenegger, Junior Group Leader, Botanical Insitute, Kiel University 
Title: Defense de-escalation as answer to adapted herbivores

Plants produce a huge diversity of secondary metabolites. Many of them are involved in the defense against herbivores. An important driving force of the evolution of this huge diversity is the ongoing adaptation of the herbivore community to the plants defense compounds. With an increasing feeding pressure, selection will favor the biosynthesis of a modified or new compound. Adapted herbivores however often store the ingested defense compound for their own protection. Thereby, the plants former defense compound become an attractant. In this case, an alternative route to escape the feeding pressure of adapted specialists is to reduce the biosynthesis of the compound. To test such a scenario of de-escalation, pyrrolizidine alkaloids (PAs) in the Apocynaceae have proven to be an interesting model system. Apocynaceae show a striking interaction with milkweed and clearwing butterflies. The butterflies use PAs not only for their own defense, they also synthesize mating pheromones from PAs. However, only few extant Apocynaceae produce PAs. We hypothesize, that in the evolutionary past, PAs were widespread in Apocynaceae species but due to the interaction with the milkweed PAs were reduced. We tested this scenario of de-escalation by reconstruction the evolution of a key enzyme of PA biosynthesis.

16:05: Questions

16:10: Closing remarks

16:15: End

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