Background: Carnivory in plants has fascinated scientists since centuries. Darwin dedicated an entire book to this phenomenon. The fascination is twofold: first, carnivory is a strong deviation from the normal lifestyle of a plant that as photosynthetic organisms would not need to take lifes from other life forms to sustain their own life. Second, carnivory appears as a typical case of "non-reducible complexity" to use the terminology of the Creationists - it is a complex trait that would not convey any selective advantage, if one element would lack. Thus, carnivory is a typical example for macroevolution. Is there a rational explanation for its evolution? Interestingly, it is found in several, non-related clades of the Angiosperm, which indicates that it cannot be so difficult to evolve carnivory. The selective advantage is to scavenge reduced nitrogen (amino groups), which means that carnivory is found in habitats where organic nitrogen is limited, such as epiphytic plants, in moors, or in soil which had been leaked out by rain.
Task: The advantages in genomics have allowed to extend molecular approaches from a few model plants (Arabidopsis, rice, grapevine) on other, more exotic species. For instance, the genomes for several carnivorous plants have been established. This allows to compare their genomic innovations with other plants that are not carnivorous. A recent paper from the Hedrich group in Würzburg has analysed these innovations in details and show that carnivory is preceded by genome duplications, such that essential genes can acquire new functions (a case of "moonlighting"), because the essential function is still fulfilled by the other copy. They can define functional complexes needed for carnivory and show, how functions that are normally having a different context, are now recruited for the new complex of carnivory. One example are proteases that are needed to digest the insects and mobilise the amino acids from them. What are these proteases doing normally, before they had been recruited for carnivory? To find this out, you have to learn and practice working with protein databases and tools therein.
The slides for this task, along with a recorded lecture on this task are available on Ilias. Note: The lecture slides can be found on Ilias (log in with your KIT credentials, if you are outside the KIT, make sure that you are linked through vpn). Path: Fakultät für Chemie und Biowissenschaften - current semester - BIO_MA_FOR_1201_Plant_Evolution)
The paper is available through the KIT web:
Palfalvi et al. (2021) Genomes of the Venus Flytrap and Close Relatives Unveil the Roots of Plant Carnivory. Curr Biol, https://doi.org/10.1016/j.cub.2020.04.051