C3-C4 intermediate photosynthesis in the Brassicaceae

The establishment of C4 photosynthesis requires considerable alterations in leaf architecture and biochemistry and evolves via intermediate states. The Brassicaceae family contains several species with a C3-C4 intermediate architecture and a limited CO2 concentration in the bundle sheath via a photorespiratory glycine pump.                       (click picture to enlange)

Diplotaxis tenuifolia

C3-C4 species can be distinguished so far by their CO2 compensation point and their bundle sheath anatomy. In the C4breed project we investigate the diversity of such glycine pump mechanisms in by parallel analysis of the genome, the anatomy and physiology in a large panel of species. The gained knowledge will help us to introduce a C3-C4 like phenotype into the C3 species Arabidopsis by a synthetic biology approach. (Researcher: Urte Schlüter)

For identification of C3-C4 photosynthesis specific regulators hybrids were created between the C3 species Moricandia moricandioides and the C3-C4 species M. arvensis and analysed for RNA sequencing. The exploration of possible cis-acting regulators could help in the identification of genes involved in the early steps of C4 photosynthesis evolution. (Reseracher: Meng-Ying Lin)

C3-C4 intermediate leaves differ from C3 leaves by alterations in metabolic balance between the mesophyll and bundle sheath cells. The shift of photorespiratory glycine decarboxylation to the bundle sheath causes changes in cell biochemistry, organelle distribution and metabolite transport between cells. In this multiplexed project we aim at elucidation of leaf cell fate control using optogenetic tools. (Researcher: Miguel Minambres Martin)


 

Molecular mechanisms of facultative Crassulacean Acid Metabolism (CAM)

CAM is one of the three modes of carbon assimilation and plants utilizing this   strategy   are   among   the   most   water-use   efficient   ones.   CAM engineering   was   therefore   proposed   as   a   strategy   towards   crop improvement. However, the molecular players of CAM regulation and the genomic blueprints thereof have not been fully deciphered, and this is where our project aims to contribute.

We have been working with   Talinum triangulare  in which CAM can be induced by exogenous abscisic acid (ABA) rapidly, making it a good experimental model to study CAM-related signalling events. Besides that, we search for additional CAM species to investigate, especially in the context of CAM evolution. We have been able to generate a couple of RNA-seq datasets and more work in the field of genomics is ongoing, namely transcriptome   and   genome   assemblies. Other   ‘omics’   data   include metabolite measurements (published and ongoing) and proteomic analysis (planned). Genome editing is another fast-developing field and its tools will enable functional studies to unravel the signalling cascade from ABA perception to CAM induction, thus elucidating the role of ABA receptors and regulatory proteins including transcription factors.

Researchers: Eva Maleckova, Vanessa Reichel-Deland


 

Maximising C4 photosynthesis in maize

Maize is an important C4 crop plant with high light, nitrogen and water use efficiency. In intensively managed maize cultures the photosynthetic performance is however still short of its theoretical maximum. In the Fullthrottle project we explore the natural photosynthetic diversity of maize lines in the field and the factors potentially lowering the efficiency of C4 photosynthesis.

Leaf Reflectance Spectrum

Measurements of photosynthetic performance are still laborious and time-consuming. The potential of leaf reflectance spectroscopy for regression model based estimation of different photosynthetically relevant parameters such as maximal assimilation, chlorophyll and nitrogen content is investigated. In the BMBF funded Fullthrottle project we collaborate with the Schön group at TUM, the Stitt and Fernie groups at MPIMP Golm, the Nikoloski group at University of Potsdam and the KWS.

Researchers Urte Schlüter, Alisandra Denton

Verantwortlich für den Inhalt: E-Mail sendenProf.Dr. Andreas Paul M. Weber