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Arabidopsis STAY-GREEN2 Is a Negative Regulator of Chlorophyll Degradation during Leaf Senescence

Cited 59 time in Web of Science Cited 62 time in Scopus
Authors
Sakuraba, Yasuhito; Park, So-Yon ; Kim, Ye-Sol ; Wang, Seung-Hyun; Yoo, Soo-Cheul; Hörtensteiner, Stefan; Paek, Nam-Chon
Issue Date
2014-08
Publisher
Oxford University Press
Citation
Molecular Plant, Vol.7 No.8, pp. 1288-1302
Keywords
농수해양Arabidopsis thalianastay-greenSGR1SGR2chlorophyll degradationleaf senescenceabiotic stress
Abstract
Chlorophyll (Chl) degradation causes leaf yellowing during senescence or under stress conditions. For Chl breakdown, STAY-GREEN1 (SGR1) interacts with Chl catabolic enzymes (CCEs) and light-harvesting complex II (LHCII) at the thylakoid membrane, possibly to allow metabolic channeling of potentially phototoxic Chl breakdown intermediates. Among these Chl catabolic components, SGR1 acts as a key regulator of leaf yellowing. In addition to SGR1 (At4g22920), the Arabidopsis thaliana genome contains an additional homolog, SGR2 (At4g11910), whose biological function remains elusive. Under senescence-inducing conditions, SGR2 expression is highly up-regulated, similar to SGR1 expression. Here we show that SGR2 function counteracts SGR1 activity in leaf Chl degradation; SGR2-overexpressing plants stayed green and the sgr2-1 knockout mutant exhibited early leaf yellowing under age-, dark-, and stress-induced senescence conditions. Like SGR1, SGR2 interacted with LHCII, but in contrast to SGR1, SGR2 interactions with CCEs were very limited. Furthermore, SGR1 and SGR2 formed homo- or heterodimers, strongly suggesting a role for SGR2 in negatively regulating Chl degradation by possibly interfering with the proposed CCE-recruiting function of SGR1. Our data indicate an antagonistic evolution of the functions of SGR1 and SGR2 in Arabidopsis to balance Chl catabolism in chloroplasts with the dismantling and remobilizing of other cellular components in senescing leaf cells.
ISSN
1674-2052
Language
English
URI
https://hdl.handle.net/10371/92815
DOI
https://doi.org/10.1093/mp/ssu045
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College of Agriculture and Life Sciences (농업생명과학대학)Dept. of Plant Science (식물생산과학부)Journal Papers (저널논문_식물생산과학부)
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