The immutans (im) variegation mutant of Arabidopsis has green and white-sectored leaves due to the absence of fully functional plastid terminal oxidase (PTOX), a plastoquinol oxidase in thylakoid membranes. PTOX appears to be at the nexus of a growing number of biochemical pathways in the plastid, including carotenoid biosynthesis, PSI cyclic electron flow, and chlororespiration. During the early steps of chloroplast biogenesis, PTOX serves as an alternate electron sink and is a prime determinant of the redox poise of the developing photosynthetic apparatus. Whereas a lack of PTOX causes the formation of photooxidized plastids in the white sectors of im, compensating mechanisms allow the green sectors to escape the effects of the mutation. This manuscript provides an update on PTOX, the mechanism of im variegation, and findings about im compensatory mechanisms.
Keywords: IMMUTANS, PTOX, variegation, chloroplast, photosynthesis, carotenoids, chloroplast biogenesis, retrograde signaling
Citation: Foudree A, Putarjunan A, Kambakam S, Nolan T, Fussell J, Pogorelko G and Rodermel S (2012) The mechanism of variegation in immutans provides insight into chloroplast biogenesis. Front. Plant Sci. 3:260. doi: 10.3389/fpls.2012.00260
Received: 21 September 2012; Accepted: 06 November 2012;
Published online: 27 November 2012.
Edited by:Tatjana Kleine, Ludwig-Maximilians-Universität München, Germany
Copyright: © 2012 Foudree, Putarjunan, Kambakam, Nolan, Fussell, Pogorelko and Rodermel. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in other forums, provided the original authors and source are credited and subject to any copyright notices concerning any third-party graphics etc.
*Correspondence: Steve Rodermel, Department of Genetics, Development, and Cell Biology, Iowa State University, 457 Bessey Hall, Ames, IA 50011, USA. e-mail: firstname.lastname@example.org