Accumulation of geranylgeranylated chlorophylls in the pigment-protein complexes of Arabidopsis thaliana acclimated to green light: effects on the organization of light-harvesting complex II and photosystem II functions

Abstract

Light quality significantly influences plant metabolism, growth and development. Recently, we have demonstrated that leaves of barley and other plant species grown under monochromatic green light (500–590 nm) accumulated a large pool of chlorophyll a (Chl a) intermediates with incomplete hydrogenation of their phytyl chains. In this work, we studied accumulation of these geranylgeranylated Chls a and b in pigment-protein complexes (PPCs) of Arabidopsis plants acclimated to green light and their structural–functional consequences on the photosynthetic apparatus. We found that geranylgeranylated Chls are present in all major PPCs, although their presence was more pronounced in light-harvesting complex II (LHCII) and less prominent in supercomplexes of photosystem II (PSII). Accumulation of geranylgeranylated Chls hampered the formation of PSII and PSI super- and megacomplexes in the thylakoid membranes as well as their assembly into chiral macrodomains; it also lowered the temperature stability of the PPCs, especially that of LHCII trimers, which led to their monomerization and an anomaly in the photoprotective mechanism of non-photochemical quenching. Role of geranylgeranylated Chls in adverse effects on photosynthetic apparatus of plants acclimated to green light is discussed.

Efficient Green Light Acclimation of the Green Algae Picochlorum sp. Triggering Geranylgeranylated Chlorophylls

“…Moreover, regarding pigments X2 and X4 the double bonds are at position P 14 -P 15 , respectively (see Figure 7 ), corresponding to the actual MH + ion [m/z] (see Table 4 ) from chlorophyll b esterified with THGG (X2) and chlorophyll a with THGG (X4). These results are in accordance to findings from purple photosynthetic bacteria (e.g., Rhodopseudomonas palustris ( Mizoguchi, Harada et al, 2006 ; Mizoguchi, Isaji et al, 2015 ), cyanobacterial mutants with an inactive of geranylgeranyl reductase gene (ChlP) ( Shpilyov, Zinchenko et al, 2005 ), diatoms ( Chaetoceros calcitrans ; ( Mizoguchi, Isaji et al, 2017 )) and higher plants exposed to green light ( Materová, Sobotka et al, 2017 ; Karlický, Materová et al, 2021 ). Chlorophylls esterified with DHGG could not be detected in this study.…”

“…However, the efficiency of photosynthesis was low. The accumulation of geranylgeranylated chlorophylls under green light was also observed for Arabidopsis thaliana in a study from 2021 ( Karlický, Materová et al, 2021 ). In this study, the comparative growth response of the eukaryotic green algae Picochlorum sp.…”

Effects of partial replacement of red by green light in the growth spectrum on photomorphogenesis and photosynthesis in tomato plants

“…The reason why RGB spectrum is less commonly used than RB is the fact that the fraction of incident light quanta successfully utilized by plants to drive electron transport is approximately 20% lower for G light than for B light (Sun et al 1998 ) and depends on the leaf’s internal structure and thickness, as well as the content of photosynthetic pigments (Falcioni et al 2017 ). Secondly, the weak absorption of leaf extracted chlorophylls a and b in the G light range contributes to the misconception that green light is only poorly absorbed by plant leaves, in contrast to blue and red light (Karlický et al 2021 ). Terashima et al ( 2009 ) demonstrated, however, that the addition of G light to the white (W) light with high photosynthetic photon flux density (PPFD) is more effective in driving photosynthesis than additional R or B light.…”

Chlorophylls: A Personal Snapshot

“…In green plants, it is generally phytol. Increasing amounts of the precursor, geranylgeraniol, are found in Arabidopsis thaliana after growth in green light [ 38 ]. The optical spectra of (B)Chls have been studied from the beginning.…”