A chloroplast envelope membrane protein containing a putative LrgB domain related to the control of bacterial death and lysis is required for chloroplast development in Arabidopsis thaliana
Article first published online: 14 SEP 2011
© 2011 The Authors. New Phytologist © 2011 New Phytologist Trust
Volume 193, Issue 1, pages 81–95, January 2012
How to Cite
Yang, Y., Jin, H., Chen, Y., Lin, W., Wang, C., Chen, Z., Han, N., Bian, H., Zhu, M. and Wang, J. (2012), A chloroplast envelope membrane protein containing a putative LrgB domain related to the control of bacterial death and lysis is required for chloroplast development in Arabidopsis thaliana. New Phytologist, 193: 81–95. doi: 10.1111/j.1469-8137.2011.03867.x
- Issue published online: 2 DEC 2011
- Article first published online: 14 SEP 2011
- Received: 16 June 2011, Accepted: 10 August 2011
- carbon partitioning;
- chloroplast development;
- leaf senescence;
- LrgB domain;
- membrane permeability;
- starch metabolism
- •A protein encoded by At1g32080 was consistently identified in proteomic studies of Arabidopsis chloroplast envelope membranes, but its function remained unclear. The protein, designated AtLrgB, may have evolved from a gene fusion of lrgA and lrgB. In bacteria, two homologous operons, lrgAB and cidAB, participate in an emerging mechanism to control cell death and lysis.
- •We aim to characterize AtLrgB using reverse genetics and cell biological and biochemical analysis.
- •AtLrgB is expressed in leaves, but not in roots. T-DNA insertion mutation of AtLrgB produced plants with interveinal chlorotic and premature necrotic leaves. Overexpression of full-length AtLrgB (or its LrgA and LrgB domains, separately), under the control of CaMV 35S promoter, produced plants exhibiting veinal chlorosis and delayed greening. At the end of light period, the T-DNA mutant had high starch and low sucrose contents in leaves, while the 35S:AtLrgB plants had low starch and high sucrose contents. Metabolite profiling revealed that AtLrgB appeared not to directly transport triose phosphate or hexose phosphates. In yeast cells, AtLrgB could augment nystatin-induced membrane permeability.
- •Our work indicates that AtLrgB is a new player in chloroplast development, carbon partitioning and leaf senescence, although its molecular mechanism remains to be established.