Alexandra Bianca Maimann

Alexandra Bianca Maimann

PhD Student

Current research

Plants produce a wide spectrum of specialized metabolites, also known as secondary metabolites, which play an important role in the interaction between the plant and its environment. One of the most extensively studied class of plant secondary metabolites are the cyanogenic glucosides (CNglcs).CNglcs are amino acid derived chemical defence compounds found in many plant species. Their biosynthesis involves two cytochrome P450 enzymes and one or two UDP-glucosyltransferases. Upon tissue damage CNglcs are hydrolyzed by a specific β-glucosidase, resulting in the release of toxic hydrogen cyanide (HCN).

In the first half of my PhD I was working on the elucidation of the CNglcs pathway in the model legume Phaseolus lunatus (Lima bean) and its genomic organisation.

My group reported the independent evolution of the biosynthetic pathways for cyanogenic glucosides, and their genomic organization in a gene cluster in Cassava (Manihot esculenta), Sorghum bicolor, and  Lotus japonicus. Biosynthetic gene clusters are increasingly recognized in plant chemical defence and consist of non-homologous genes of the pathway that are co-localized in the same genomic region. To determine the evolutionary dynamics of biosynthetic gene clusters, we further investigated the pathway for CNglcs within the legume plant family.

In the second half of my PhD I am working on the characterization of the degradation pathway of cyanogenic glucosides in sweet and bitter almonds (Prunus dulcis) during germination. This goal will be achieved by doing LC-MS/MS analysis in seed tissue during different developmental stages, Transcriptomics, RT-qPCR, Protein assays of the identified genes that were differentially expressed.

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