The Role of Selected Wavelengths of Light in the Activity of Photosystem II in Gloeobacter violaceus

Abstract

Gloeobacter violaceus is a cyanobacteria species with a lack of thylakoids, while photosynthetic antennas, i.e., phycobilisomes (PBSs), photosystem II (PSII), and I (PSI), are located in the cytoplasmic membrane. We verified the hypothesis that blue–red (BR) light supplemented with a far-red (FR), ultraviolet A (UVA), and green (G) light can affect the photosynthetic electron transport chain in PSII and explain the differences in the growth of the G. violaceus culture. The cyanobacteria were cultured under different light conditions. The largest increase in G. violaceus biomass was observed only under BR + FR and BR + G light. Moreover, the shape of the G. violaceus cells was modified by the spectrum with the addition of G light. Furthermore, it was found that both the spectral composition of light and age of the cyanobacterial culture affect the different content of phycobiliproteins in the photosynthetic antennas (PBS). Most likely, in cells grown under light conditions with the addition of FR and G light, the average antenna size increased due to the inactivation of some reaction centers in PSII. Moreover, the role of PSI and gloeorhodopsin as supplementary sources of metabolic energy in the G. violaceus growth is discussed.

PEG-induced physiological drought for screening winter wheat genotypes sensitivity – integrated biochemical and chlorophyll a fluorescence analysis

“…Since the IP phase depends on the efficiency of the PSI acceptor’s electron uptake and the number of available oxidized forms of NADP, the negative values ​​of the IP phase (the data of which are not presented in this paper but can be correlated to V I ) in genotypes of Cluster 4 corresponded to a larger number of oxidized forms of NADP (NADP+) molecules per active center. This was reflected in the lower need for reductants on the PSI acceptor side ( Ceppi et al., 2011 ; Pollastrini et al., 2014 ; Kula-Maximenko et al., 2021 ) and could be a compensatory mechanism for seedlings that have evolved in response to suboptimal environmental conditions.…”

“…Since the IP phase depends on the efficiency of the PSI acceptor's electron uptake and the number of available oxidized forms of NADP, the negative values of the IP phase (the data of which are not presented in this paper but can be correlated to V I ) in genotypes of Cluster 4 corresponded to a larger number of oxidized forms of NADP (NADP+) molecules per active center. This was reflected in the lower need for reductants on the PSI acceptor side (Ceppi et al, 2011;Pollastrini et al, 2014;Kula-Maximenko et al, 2021) and could be a compensatory mechanism for seedlings that have evolved in response to suboptimal environmental conditions. Since every change in the OJIP curve is reflected in the index of photosynthetic efficiency (PI TOT ) -an energy conversion from exciton to the reduction of the final electron acceptor in PSI (Zivcak et al, 2014;Kalaji et al, 2016;Kalaji et al, 2017;Tsimilli-Michael, 2020), PI TOT showed to be the most sensitive parameter of the JIP-test in detecting and comparing the intensity of stress effect among tested genotypes.…”

Photosynthetic Reactions: From Molecules to Function, and from Simple Models to Complex Systems

“…Kula-Maximenko et al investigated the growth of Gleobacter under blue–red light supplemented with a far-red, ultraviolet A, and green light. Interestingly, they found that the light composition influenced not only the overall yield of biomass production, but also the shape of the cells, as well as inducing changes in particular components of the light-dependent reaction chain [ 5 ]. At most, this influenced the content of the auxiliary antennae.…”