Chloroplast NADH Dehydrogenase-Like Complex as Part of Cyclic Electron Transport around Photosystem I in C3 and C4 Plants

Abstract The review is devoted to the analysis of the chloroplast NADH dehydrogenase-like complex (NDH complex), which is involved in the cyclic electron transport (CET) of photosystem I (PSI), in plants with different types of photosynthetic metabolism. NDH mediated CET PSI is associated with the mechanism of resistance and antioxidant protection, and also plays an important role in the functioning of different types of carbon-concentrating mechanism (CCM) (C2 (C3–C4), C4-NAD, C4-NADP). The chloroplast NDH complex is an Fd-dependent plastoquinone reductase, consists of at least 29 subunits, which are organized in 5 subcomplexes (M, A, E, B and L) and can form supercomplexes with one or two PSI. Bioinformatic analysis of plastid ndh genes in 20 species of Chenopodiaceae with different types of photosynthesis showed the greatest differences between species in the nucleotide sequences of ndhF, ndhD, ndhH and ndhK genes (encoded the subunits of M and A subcomplexes, which form the membrane and hydrophilic arms of the NDH complex). The formation of separate clusters of species with C3 photosynthesis and with СCM (C4 and C3–C4) is shown only for ndhF subunit. Comparison of the ndhF amino acid sequence showed the greatest differences in the region of 1–2 loops (which associate with the PnsB2 and PnsB3 subunits) and the H-helix (necessary for stabilization of the membrane arm of the complex). In general, the review presents an analysis of literary data and results of own studies regarding the structure, localization, functioning and regulation of the chloroplast NDH complex in C3 and C4 species. The possibilities of ndh genes use for phylogenetic analysis and characterization of the type of photosynthetic metabolism are discussed.