Chloroplast and photosystems: Impact of cadmium and iron deficiency

Abstract

Chloroplasts utilize photons from solar radiation to synthesize energy-rich molecules of ATPs and NADPHs, which are further used in active cellular processes. Multiprotein complexes (MPCs), including photosystems (PSII and PSI), and the cellular architecture responsible for generation of the proton motive force and the subsequent photophosphorylation, mediate the task of ATP and NADPH synthesis. Both photosystems and other multiprotein assemblies are embedded in thylakoid membranes. Advances in techniques used to study structural biology, biophysics, and comparative genomics and proteomics have enabled us to gain insights of structure, function, and localization of each individual component of the photosynthetic apparatus. An efficient coordination among MPCs is essential for normal functioning of photosynthesis, but there are various stressors that might directly or indirectly interact with photosynthetic components and processes. Cadmium is one of the toxic heavy metals that interact with photosynthetic components and damage photosystems and other MPCs in thylakoids. In plants, iron deficiency shows similar symptoms as those caused by Cd. Our article provides a general overview of chloroplast structure and a critical account of Cd-induced changes in photosystems and other MPCs in thylakoids, and suggests the possible mechanisms involved in mediating these changes. The connection between Cd-induced Fe-deficiency and the elevated Cd toxicity under the Fe-deficient condition was also discussed. inner membrane of chloroplast; TOC -translocons at outer membrane of chloroplast; BNP -blue native PAGE; SDS -sodium dodecylsulfate; PAGE -polyacrylamide gel electrophoresis; pmf -proton motive force; PMF -peptide mass fingerprinting; iTRAQ -isobaric tag for relative and absolute quantitation; CP -chloroplast.

Candidate Genes for Yellow Leaf Color in Common Wheat (Triticum aestivum L.) and Major Related Metabolic Pathways according to Transcriptome Profiling

“…Yellow leaf color formation is related to chloroplast development, where chloroplasts comprise the chloroplast membrane, thylakoid, and matrix, which are the main sites for photosynthesis. In higher plants, the multi-subunit pigment–protein complexes (i.e., photosystem (PS)I, PSII, light harvesting complexes, cytochrome b6/f, and ATP synthase) are embedded in the highly folded thylakoid membrane where they are responsible for light absorption and energy transfer [ 71 , 72 ]. The photosynthetic light reaction occurs in the thylakoid in chloroplasts, and thus we suggest that changes in gene expression might have been related to thylakoid development and photosynthesis in the two progeny of Ygm .…”

Changes in Conyza canadensis (L.) cronquist leaf anatomy under caprylic acid stress

“…Photons can be utilized by chloroplasts from solar radiation to synthesize energyrich molecules such as ATPs and NADPHs, which are further utilized in active cellular processes. Various stressors might be directly or indirectly interacted with photosynthetic components and processes such as heavy metals (Bashir, 2015;Muhammad et al, 2016) and drought (Keshav & Vanlerberghe, 2017). Mitochondria in mesophyll cells also suffered injury under caprylic acid treatments.…”

Integrated physiological and transcriptomic analyses responses to altitude stress in oat (Avena sativa L.)

“…Chloroplasts are the main sites for photosynthesis which are comprised of membranes, thylakoid system, and stroma with functional units in it. In higher plants, the multi-subunit pigment-protein complexes (i.e., photosystem (PS) I, PSII, light harvesting complexes, cytochrome b6/f, and ATP synthase) are embedded in the highly folded thylakoid membrane where they are responsible for light absorption and energy transfer [36]. Strong radiation in high-altitude environments might have been related to thylakoid development and photosynthesis at the two different altitudes.…”