Plant Stress and Phenomics Group

Research topics

1, Investigation photosynthetic electron transport processes by biophysical measurements and in silico modelling

2, The role of singlet oxygen in photodamage of the photosynthetic apparatus

3, Cyanobacterial biosensors

4, Coral symbiosis

5, Plant- and algal phenomics, microfluidics

6, Metagenomic analysis of microbial communities in natural water bodies

Instruments

previous group members

Important Recent publications

Research topics

1, Investigation photosynthetic electron transport processes by biophysical measurements and in silico modelling

The initial, light-dependent events of photosynthesis, which serve as a basis for the biosphere on Earth, take place in pigment-protein complexes embedded in, or associated with, the thylakoid membrane. These complexes are Photosystem II (PSII), performing the splitting of water to electrons, protons and oxygen, Photosystem I (PSI), providing the reducing power for NADPH production, and cytochrome b₆f (cytb₆f) mediating electron transport between PSII and PSI. A further important, although not pigmented, complex is ATP-ase, which produces ATP, required for CO₂ fixation and other cellular process, by utilizing the proton gradient formed between the two sides of the thylakoid membrane. Investigation of electron transport processes, which take place in a wide time scale (10^-9 – 10¹ s) can be significantly simplified by using modelling approaches. Our goal is to develop an in silico model to describe the complete network of electron transport components which are part of or associated with the thylakoid embedded complexes. The model makes possible to perform virtual experiments to assess the kinetic changes in the whole timescale of electron transport components, which are not easily accessible by direct measurements, and can also be used for finding the optimal conditions for targeted measurements.

Network of electron transport components of the cyanobacterial thylakoid membrane

An important area of our research is the investigation of alternative electron transport processes, with special emphasis on cyclic electron flow (CEF) around PSI. A useful approach to study this process is the wave phenomenon of flash-induced Chl fluorescence relaxation which was discovered earlier by our group in cyanobacteria. Recently we have demonstrated that the fluorescence wave phenomenon is also present in other microalga species (green algae, dinoflagellates, etc.), and can be used the study various CEF pathways.

2, The role of singlet oxygen in photodamage of the photosynthetic apparatus

Although light is the primary driving force of photosynthesis light is also an important damaging agent of the photosynthetic apparatus, especially of PSII. Reactive oxygen species, especially singlet oxygen (¹O₂), play an important role in this so called photoinhibition process. Our aim in this field is the clarification of the mechanisms of photodamage, with special emphasis on the role of ¹O₂. Earlier we have developed a method for the detection ¹O₂ production rate in intact microalgal cells, which has proven very useful for studying the damaging role of ¹O₂. Our recent results show that besides its damaging effect ¹O₂ plays also an important role in inducing the expression of various genes in Synechocystis 6803 that are involved in photoprotection mechanisms, among other functions.

Detection of singlet oxygen by His-mediated oxygen uptake

3, Cianobakterial biosensors

Reliable and efficient detection of environmental pollutants, such heavy metals, is an important research target. The Synechocystis 6803 cyanobacterium contains several genes, whose protein products are involved in heavy metal homeostasis. Earlier we have constructed Synechocystis-based heavy metal bioreporter strains by using the fusion of heavy metal inducible promoters with the lux genes that code for the luciferase protein. These cells respond to the presence of heavy metal ions (e.g. Co²⁺, Ni⁺, Zn²⁺) with bioluminescence emission and can be used as biosensors after calibration. Our recent findings show that the sensitivity of the heavy metal bioreporter strains can be significantly increased by inactivation of genes that encode heavy metal efflux transporters and thereby make possible the detection of Co²⁺, Ni⁺, Zn²⁺ contamination levels within the limit limits of affecting human health.

By using a newly identified ¹O₂-responsive promoter we have recently constructed a ¹O₂ reporting Synechocystis strain, which makes possible direct monitoring of intracellular ¹O₂ levels under various conditions.

Luminescent Synechocystis bioreporter construct

4, Coral symbiosis

The dinoflagellate algae, Symbiodiniaceae, play a crucial role in coral symbiosis. The symbiotic association in corals between the cnidarian host (Anthozoa) and the photosynthetic algae, Symbiodiniaceae, is a delicately regulated mutualistic relationship, which however is critically threatened by global climate change. In our group, we investigate the photosynthetic processes of Symbiodiniaceae under various environmental stress conditions (heat, light, change in nutrient content). Furthermore, we investigate the role and function of certain components of the alternative electron transport processes in the symbiotic algae.

The corals of the Great Barrier Reef and the coral endosymbiont algae, Symbiodiniaceae (own photos)

5, Plant- and alga phenomics, microfluidics

A rapidly developing field of plant sciences is plant phenomics which allows precise monitoring of the development and physiological status of plants under controlled growth conditions by using the combination of various remote sensing and imaging methods. In our group we are developing and using (medium) high throughput plant phenotyping platforms for studying stress tolerance of various agriculturally important plants (e.g. wheat, tomato, potato, maize, etc.). An important area of our research is the development of affordable low cost phenotyping solutions.

 We have extended the phenotyping approach to unicellular microalgae by using the combination of imaging-based photosynthetic activity measurements and hyperspectral imaging.

Plant phenotyping platform

 An important area of algal phenomics is the combination of microfluidic systems with photosynthetic activity imaging. This powerful approach makes possible the investigation of photosynthetic activity and morphological characteristics at single cell level.

Morphological changes of a Symbiodinium cell trapped in a microfluidic chamber during enzymatic digestion of the cell wall (protoplastation).

6. Metagenomic analysis of microbial communities in natural water bodies

In our natural environment diverse organisms thrive together in close multifaceted connections in microbial consortia that respond to environmental stimuli and shape their overall traits jointly. On the other hand, environmental conditions such as availability of nutrients and light, the pH, and ionic strengths have fundamental effects on the composition of the communities. Hence, investigation of the distribution and abundance of the participating microbes and their combined gene repertoires in environmental samples may help us draw conclusions on changes in environmental conditions and facilitate practical applications of microbes.

Based on this approach we carry out metagenomic investigations of natural environmental samples. We have studied potential agricultural applications of bacterial consortia on leaves, antibiotic markers in natural water bodies under urban exposure, and the effects of global warming on the microbial communities of rivers, among others.

The most abundant microbial eukaryotic orders in four samples of two environmental sampling loci each

Instruments

Oxygen polarography: For measurements of oxygen production rate under continuous light and single turnover flash excitation.

DUAL-PAM measuring system: Parallel measurements of chlorophyll and NADPH fluorescence, as well as P700⁺ absorption changes.

Photon Systems Instruments (PSI) FL-3500: Variable Chl fluorescence measurements un continuous light and single turnover flash excitation.

Chlorophyll fluorescence imaging systems: Variable Chl fluorescence imaging from microscopic to macroscopic (15*15) cm scale

Microfluidic System: Single cell level monitoring of morphology and photosynthetic activity of microalgae.

Thermoluminescence: Photosynthetic activity measurements to study the functioning of Photosystem II in isolated membrane complexes, intact algae and plant leaves.

Plant phenotyping platforms: (i) Fully automatic (PSI) system for 100-400 middle sized plants. (ii) Home built semi-automatic system up to 200 middle sized plants. (iii) Home built low cost, Internet of Things (IoT) based system for small plants.

Membrane Inlet Mass Spectrometer (MIMS, PSI MS-GAS 100): Detection of low molecular mass (<100) volatile metabolites

Microalgae culturing: Photobioreactors, culturing incubators

PREVIOUS GROUP MEMBERS

Zsuzsanna Deák (PhD thesis 1993, https://doktori.bibl.u-szeged.hu/id/eprint/5542/1/1993_deak_zsuzsanna.pdf)

Cornelia Spetea (PhD thesis 1996, https://doktori.bibl.u-szeged.hu/id/eprint/4583/1/1996_cornelia_spetea.pdf)

Zoltán Máté (PhD thesis 2000, https://doktori.bibl.u-szeged.hu/id/eprint/4307/1/2000_mate_zoltan.pdf)

Cosmin Sicora (PhD thesis 2003, https://doktori.bibl.u-szeged.hu/id/eprint/149/1/2003_cosmin_ionel_sicora.pdf)

Otilia Silvia Cheregi (PhD thesis 2008, https://doktori.bibl.u-szeged.hu/id/eprint/1143/1/Thesis_on_CD.pdf)

Loredana Peca (PhD thesis 2009, https://doktori.bibl.u-szeged.hu/id/eprint/7487/1/2009_peca_loredana.pdf)

Krisztián Cser (PhD studies, 2005-2009)

Leyla Abasova (PhD thesis 2011, https://doktori.bibl.u-szeged.hu/id/eprint/1282/1/Dissertation.pdf)

Éva Kiss (PhD thesis 2012, https://doktori.bibl.u-szeged.hu/id/eprint/1664/1/Kiss_%C3%89va_disszert%C3%A1ci%C3%B3.pdf)

Csaba István Nagy (PhD thesis 2014, https://doktori.bibl.u-szeged.hu/id/eprint/2415/1/NCsabaPhD2014.pdf)

István Zoltán Vass (PhD thesis 2014, https://doktori.bibl.u-szeged.hu/id/eprint/2238/1/Vass_disszert%C3%A1ci%C3%B3.pdf)

Ateeq ur Rehman (PhD thesis 2016, https://doktori.bibl.u-szeged.hu/id/eprint/2987/2/PhD%20Thesis_Ateeq%20ur%20Rehman.pdf)

Kenny Paul (PhD thesis 2016, https://doktori.bibl.u-szeged.hu/id/eprint/2970/9/Kenny%20Paul-disszertacio.pdf)

Sandeesha Kodru (PhD thesis 2021, https://doktori.bibl.u-szeged.hu/id/eprint/11072/1/PhD%20THESIS%20SANDEESHA%202021116_final.pdf)

Faiza Bashir (PhD thesis 2021, https://doktori.bibl.u-szeged.hu/id/eprint/11071/2/thesis%20booklet%20Faiza%20Bashir.pdf)

Gábor Patyi (PhD thesis 2022, https://doktori.bibl.u-szeged.hu/id/eprint/11413/1/PG_PhD_diszertacio.pdf)

Important recent publications

Aslam SM, Vass I, Szabo M (2023) Characterization of the Flash-Induced Fluorescence Wave Phenomenon in the Coral Endosymbiont Algae, Symbiodiniaceae. International Journal of Molecular Sciences 24 (10). doi:10.3390/ijms24108712

Bashir F, Kovacs S, Abraham A, Nagy K, Ayaydin F, Valkony-Kelemen I, Ferenc G, Galajda P, Toth SZ, Sass L, Kos PB, Vass I, Szabo M (2022) Viable protoplast formation of the coral endosymbiont alga Symbiodinium spp. in a microfluidics platform. Lab on a Chip 22 (16):2986-2999. doi:10.1039/d2lc00130f

Patil PP, Vass I, Szabo M (2022) Characterization of the Wave Phenomenon in Flash-Induced Fluorescence Relaxation and Its Application to Study Cyclic Electron Pathways in Microalgae. International Journal of Molecular Sciences 23 (9). doi:10.3390/ijms23094927

Kondic-Spika A, Mikic S, Mirosavljevic M, Trkulja D, Jeromela AM, Rajkovic D, Radanovic A, Cvejic S, Glogovac S, Dodig D, Bozinovic S, Satovic Z, Lazarevic B, Simic D, Novoselovic D, Vass I, Pauk J, Miladinovic D (2022) Crop breeding for a changing climate in the Pannonian region: towards integration of modern phenotyping tools. Journal of Experimental Botany 73 (15):5089-5110. doi:10.1093/jxb/erac181

Bashir F, Rehman AU, Szabo M, Vass I (2021) Singlet oxygen damages the function of Photosystem II in isolated thylakoids and in the green alga Chlorella sorokiniana. Photosynthesis Research 149 (1-2):93-105. doi:10.1007/s11120-021-00841-3

Patyi G, Hodi B, Solymosi D, Vass I, Kos PB (2021) Increased sensitivity of heavy metal bioreporters in transporter deficient Synechocystis PCC6803 mutants. Plos One 16 (12). doi:10.1371/journal.pone.0261135

Rehman AU, Bashir F, Ayaydin F, Kota Z, Pali T, Vass I (2021) Proline is a quencher of singlet oxygen and superoxide both in in vitro systems and isolated thylakoids. Physiologia Plantarum 172 (1):7-18. doi:10.1111/ppl.13265

Kodru S, Rehman AU, Vass I (2020) Chloramphenicol enhances Photosystem II photodamage in intact cells of the cyanobacteriumSynechocystisPCC 6803. Photosynthesis Research 145 (3):227-235. doi:10.1007/s11120-020-00784-1

Patil PP, Vass I, Kodru S, Szabo M (2020) A multi-parametric screening platform for photosynthetic trait characterization of microalgae and cyanobacteria under inorganic carbon limitation. Plos One 15 (7). doi:10.1371/journal.pone.0236188