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‘ happy on norflurazon ’ ( hon ) mutations implicate perturbance of plastid homeostasis with activating stress acclimatization and changing nuclear gene expression in norflurazon‐treated seedlings
Author(s) -
Saini Geetanjali,
Meskauskiene Rasa,
Pijacka Wioletta,
Roszak Pawel,
Sjögren Lars L. E.,
Clarke Adrian K.,
Straus Marco,
Apel Klaus
Publication year - 2011
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2010.04454.x
Subject(s) - plastid , mutant , biology , retrograde signaling , nuclear gene , microbiology and biotechnology , acclimatization , gene , nuclear localization sequence , gene expression , genetics , chloroplast , genome
Summary Various mutant screens have been undertaken to identify constituents involved in the transmission of signals from the plastid to the nucleus. Many of these screens have been performed using carotenoid‐deficient plants grown in the presence of norflurazon (NF), an inhibitor of phytoene desaturase. NF‐treated plants are bleached and suppress the expression of nuclear genes encoding chloroplast proteins. Several genomes uncoupled ( gun ) mutants have been isolated that de‐repress the expression of these nuclear genes. In the present study, a genetic screen has been established that circumvents severe photo‐oxidative stress in NF‐treated plants. Under these modified screening conditions, happy on norflurazon ( hon ) mutants have been identified that, like gun mutants, de‐repress expression of the Lhcb gene, encoding a light‐harvesting chlorophyll protein, but, in contrast to wild‐type and gun mutants, are green in the presence of NF. hon mutations disturb plastid protein homeostasis, thereby activating plastid signaling and inducing stress acclimatization. Rather than defining constituents of a retrograde signaling pathway specifically associated with the NF‐induced suppression of nuclear gene expression, as proposed for gun , hon mutations affect Lhcb expression more indirectly prior to initiation of plastid signaling in NF‐treated seedlings. They pre‐condition seedlings by inducing stress acclimatization, thereby attenuating the impact of a subsequent NF treatment.