evolution; leaf senescence; seed maturation; pathway diversity; chlorophyll breakdown; phyllobilin
Aubry Sylvain, Fankhauser Niklaus, Ovinnikov Serguei, Pružinská Adriana, Stirnemann Marina, Zienkiewicz Krzysztof, Herrfurth Cornelia, Feussner Ivo, Hörtensteiner Stefan (2020), Pheophorbide a May Regulate Jasmonate Signaling during Dark-Induced Senescence, in Plant Physiology
, 182(2), 776-791.
Hu Xueyun, Jia Ting, Hörtensteiner Stefan, Tanaka Ayumi, Tanaka Ryouichi (2020), Subcellular localization of chlorophyllase2 reveals it is not involved in chlorophyll degradation during senescence in Arabidopsis thaliana, in Plant Science
, 290, 110314-110314.
Xie Zuokun, Wu Shengdong, Chen Junyi, Zhu Xiaoyu, Zhou Xin, Hörtensteiner Stefan, Ren Guodong, Kuai Benke (2019), The C-terminal cysteine-rich motif of NYE1/SGR1 is indispensable for its function in chlorophyll degradation in Arabidopsis, in Plant Molecular Biology
, 101(3), 257-268.
Süssenbacher Iris, Menghini Damian, Scherzer Gerhard, Salinger Kathrin, Erhart Theresia, Moser Simone, Vergeiner Clemens, Hörtensteiner Stefan, Kräutler Bernhard (2019), Cryptic chlorophyll breakdown in non-senescent green Arabidopsis thaliana leaves, in Photosynthesis Research
, 142(1), 69-85.
Moles Tommaso Michele, de Brito Francisco Rita, Mariotti Lorenzo, Pompeiano Antonio, Lupini Antonio, Incrocci Luca, Carmassi Giulia, Scartazza Andrea, Pistelli Laura, Guglielminetti Lorenzo, Pardossi Alberto, Sunseri Francesco, Hörtensteiner Stefan, Santelia Diana (2019), Salinity in Autumn-Winter Season and Fruit Quality of Tomato Landraces, in Frontiers in Plant Science
, 10, 1078.
Durgud Meriem, Gupta Saurabh, Ivanov Ivan, Omidbakhshfard M. Amin, Benina Maria, Alseekh Saleh, Staykov Nikola, Hauenstein Mareike, Dijkwel Paul P., Hörtensteiner Stefan, Toneva Valentina, Brotman Yariv, Fernie Alisdair R., Mueller-Roeber Bernd, Gechev Tsanko S. (2018), Molecular Mechanisms Preventing Senescence in Response to Prolonged Darkness in a Desiccation-Tolerant Plant, in Plant Physiology
, 177(3), 1319-1338.
Guyer Luzia, Salinger Kathrin, Krügel Undine, Hörtensteiner Stefan (2018), Catalytic and structural properties of pheophytinase, the phytol esterase involved in chlorophyll breakdown, in Journal of Experimental Botany
, 69(4), 879-889.
Kuai Benke, Chen Junyi, Hörtensteiner Stefan (2018), The biochemistry and molecular biology of chlorophyll breakdown, in Journal of Experimental Botany
, 69(4), 751-767.
Das Aditi, Guyer Luzia, Hörtensteiner Stefan (2018), Chlorophyll and Chlorophyll Catabolite Analysis by HPLC, Springer New York, New York, NY, 223-235.
Christ Bastien, Hochstrasser Ramon, Guyer Luzia, Francisco Rita, Aubry Sylvain, Hörtensteiner Stefan, Weng Jing-Ke (2017), Non-specific activities of the major herbicide-resistance gene BAR, in Nature Plants
, 3(12), 937-945.
Hauenstein Mareike, Hörtensteiner Stefan (2017), Isolation and Detection of the Chlorophyll Catabolite Hydroxylating Activity from Capsicum annuum Chromoplasts, in BIO-PROTOCOL
, 7(18), e2561.
The so-called PAO/phyllobilin pathway of chlorophyll breakdown consists of two parts. First, chlorophyll is converted to a primary fluorescent chlorophyll catabolite (pFCC) with PHEOPHORBIDE A OXYGENASE (PAO) as the key enzyme. In the second part, pFCC is modified by different enzymes to ultimately produce a species-specific variety of final chlorophyll degradation products, so-called phyllobilins, which accumulate in the vacuole of senescent cells. Phyllobilins have been identified from more than twenty angiosperm species, mostly in senescent leaves. Accordingly, it has been considered that the PAO/phyllobilin pathway is highly conserved within higher plants. Even though almost all enzymatic steps of the first part of the PAO/phyllobilin pathway have been elucidated in the past, there are open questions regarding (i) the conservation of the pathway in different tissues within a given species, (ii) the degree of pathway diversity among different angiosperm species, including the molecular identity of several phyllobilin-modifying enzymes, and (iii) the evolutionary origin and phylogenetic distribution and diversity of the enzymes of the pathway. This proposal aims to address some of these aspects by answering the following questions:- How can tissue-specific differences in phyllobilin formation be explained?- How diverse is the occurrence of phyllobilins within photosynthetic organisms?- How widely distributed and how similar are the enzymes that catalyze PAO/phyllobilin pathway reactions?- What is the molecular identity of so far unknown activities within the pathway?To answer these questions, a variety of molecular, biochemical and analytical methods will be used. These include (i) analysis of enzyme activities, (ii) classical protein purification, (iii) production of transgenic plants by classical T-DNA- and CRISPR/Cas9-based methods and their analysis, (iv) phyllobilin analysis by liquid chromatography-mass spectrometry, (v) genome-wide association studies and (vi) bioinformatics- and proteomics-based identification of candidate proteins.Breakdown of chlorophyll is a physiological process that has a broad impact for daily life; among other aspects it is relevant for the food industry, for example the shelf life of leafy vegetables and fruits, and for the amenity sector, for example turf grass systems. With this in mind, it seems surprising that the mechanism of chlorophyll breakdown so far mainly focused on a few angiosperm model species. This proposal aims to get a better picture about the extent of existence and variability of the PAO/phyllobilin pathway within the lineage of oxygenic photosynthetic organisms and about its evolutionary origin.