Photosynthetica 2015, 53(3):321-335 | DOI: 10.1007/s11099-015-0152-z

Chloroplast and photosystems: Impact of cadmium and iron deficiency

H. Bashir¹, M. I. Qureshi¹, M. M. Ibrahim^2,3, M. Iqbal^4,*

¹ Department of Biotechnology, Faculty of Natural Sciences, Jamia Millia Islamia, New Delhi, India

² Botany & Microbiology Department, Science College, King Saud University, Riyadh, Saudi Arabia

³ Botany & Microbiology Department, Faculty of Science, Alexandria University, Alexandria, Egypt

⁴ Department of Botany, Faculty of Science, Jamia Hamdard, New Delhi, India

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.

Keywords: grana; light-harvesting complex; photosynthesis; stroma; thylakoids

Received: January 1, 2014; Accepted: April 27, 2015; Published: September 1, 2015Show citation