Leaf-variegated mutations and their responsible genes in Arabidopsis thaliana.

Sakamoto, Wataru

doi:10.1266/ggs.78.1

Cited by 102 publications

(108 citation statements)

References 82 publications

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“…Mutations in FtsH2, whose transcript and protein levels are the highest within the family, cause severe leaf variegation (Chen et al, 2000;Takechi et al, 2000). Mutations in FtsH5, whose transcript and protein levels are lower, lead only to slight variegation that disappears with development (Sakamoto et al, 2002;Sakamoto, 2003). Protein levels of FtsH1 and 8 are lower, and, in accordance, mutants of these are indistinguishable from wild-type plants.…”

Section: Discussionmentioning

confidence: 72%

Expression in Multigene Families. Analysis of Chloroplast and Mitochondrial Proteases

Sinvany-Villalobo

Davydov²,

Ben-Ari³

et al. 2004

Plant Physiology

119

107

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The proteolytic machinery of chloroplasts and mitochondria in Arabidopsis consists primarily of three families of ATPdependent proteases, Clp, Lon, and FtsH, and one family of ATP-independent proteases, DegP. However, the functional significance of the multiplicity of their genes is not clear. To test whether expression of specific isomers could be differently affected by growth conditions, we analyzed transcript abundance following short-term exposure to different environmental stimuli, using 70-mer oligonucleotide arrays. This analysis revealed variability in the response to high light and different temperatures within members of each family. Thirty out of the 41 tested genes were up-regulated in response to high light, including both chloroplast and mitochondrial isozymes, whereas only six and five genes responded to either high or low temperature, respectively. The extent of response was variable, ranging from 2-to 20-fold increase in the steady-state levels.Absolute transcript levels of the tested genes, compiled from one-channel arrays, were also variable. In general, transcripts encoding mitochondrial isozymes were accumulated to a lower level than chloroplastic ones. Within the FtsH family, transcript abundance of most genes correlated with the severity of mutant phenotypes in the relevant genes. This correlation was also evident at the protein level. Analysis of FtsH isozymes revealed that FtsH2 was the most abundant species, followed by FtsH5 and 8, with FtsH1 being accumulated to only 10% of FtsH2 level. These results suggest that, unlike previous expectations, the relative importance of different chloroplast protease isozymes, evidenced by mutant phenotypes at least in the FtsH family, is determined by their abundance, and not necessarily by different specific functions or specialized expression under certain conditions.The proteolytic machinery of chloroplasts and mitochondria is essential for controlling the quality and turnover of these organelles' proteins and, thus, is important for their proper function. In Arabidopsis, the proteolytic machinery of chloroplasts consists primarily of three families of ATP-dependent proteases, Clp, Lon, and FtsH, and one family of ATPindependent proteases, DegP (for review, see Adam and Clarke, 2002;Sokolenko et al., 2002). Homologous enzymes are found also in mitochondria (Sarria et al., 1998;Adam et al., 2001;Halperin et al., 2001b;Kolodziejczak et al., 2002). All these families have well-characterized homologs in Escherichia coli (for review, see Clarke, 1999;Adam, 2000). Clp is a Ser protease that separates its two essential functions in two different polypeptides: a small subunit, ClpP, containing the proteolytic active site, and a larger regulatory ATPase subunit, either ClpA or ClpX (for review, see Gottesman, 1996). Lon protease is an ATPdependent Ser protease in which the catalytic and ATPase domains reside in a single polypeptide (for review, see Gottesman, 1996). FtsH is the only essential ATP-dependent protease in E. coli. It is a membranebound metall...

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Section: Discussionmentioning

confidence: 72%

Expression in Multigene Families. Analysis of Chloroplast and Mitochondrial Proteases

Sinvany-Villalobo

Davydov²,

Ben-Ari³

et al. 2004

Plant Physiology

119

107

View full text Add to dashboard Cite

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“…Numerous genetic mutations are shown to alter chloroplast functions, many producing variegation phenotypes (Sakamoto, 2003;Yu et al, 2007). Yet, no association has been reported of these mutations with similar, developmental reprogramming, implying that a specificity of function rather than a general organellar perturbation conditions the msh1 changes.…”

Section: Discussionmentioning

confidence: 99%

The Chloroplast Triggers Developmental Reprogramming When MUTS HOMOLOG1 Is Suppressed in Plants

Santamaria

Virdi

et al. 2012

Plant Physiology

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Multicellular eukaryotes demonstrate nongenetic, heritable phenotypic versatility in their adaptation to environmental changes. This inclusive inheritance is composed of interacting epigenetic, maternal, and environmental factors. Yet-unidentified maternal effects can have a pronounced influence on plant phenotypic adaptation to changing environmental conditions. To explore the control of phenotypy in higher plants, we examined the effect of a single plant nuclear gene on the expression and transmission of phenotypic variability in Arabidopsis (Arabidopsis thaliana). MutS HOMOLOG1 (MSH1) is a plant-specific nuclear gene product that functions in both mitochondria and plastids to maintain genome stability. RNA interference suppression of the gene elicits strikingly similar programmed changes in plant growth pattern in six different plant species, changes subsequently heritable independent of the RNA interference transgene. The altered phenotypes reflect multiple pathways that are known to participate in adaptation, including altered phytohormone effects for dwarfed growth and reduced internode elongation, enhanced branching, reduced stomatal density, altered leaf morphology, delayed flowering, and extended juvenility, with conversion to perennial growth pattern in short days. Some of these effects are partially reversed with the application of gibberellic acid. Genetic hemicomplementation experiments show that this phenotypic plasticity derives from changes in chloroplast state. Our results suggest that suppression of MSH1, which occurs under several forms of abiotic stress, triggers a plastidial response process that involves nongenetic inheritance.

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“…The deletion of ftsH is lethal in E. coli (Tomoyasu et al, 1993) and causes a severe growth defect in Bacillus subtilis (Deuerling et al, 1997). Similarly, leaf variegation appears as a typical phenotype of FtsH deficiency in higher plants (Sakamoto, 2003). The loss of VAR1 or VAR2 is accompanied by a decline in PSII activity when plants are exposed to high light (Bailey et al, 2002;Sakamoto et al, 2002).…”

Section: Leaf Variegation and Inactivation Of The Ftsh Gene Familymentioning

confidence: 99%

“…Mutations in FtsHs have been shown to correlate with leaf variegation (Sakamoto, 2003). A genetic screen of leaf-variegated mutants in Arabidopsis identified a category of nuclear recessive mutants, yellow variegated ( var1 and var2 ), in which chloroplast development and maintenance are impaired (Martínez-Zapater, 1993;Chen et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Coordinated Regulation and Complex Formation of YELLOW VARIEGATED1 and YELLOW VARIEGATED2, Chloroplastic FtsH Metalloproteases Involved in the Repair Cycle of Photosystem II in Arabidopsis Thylakoid Membranes

et al. 2003

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Arabidopsis YELLOW VARIEGATED1 ( VAR1 ) and VAR2 are separate loci that encode similar chloroplast FtsH proteases. To date, FtsH is the best-characterized protease in thylakoid membranes involved in the turnover of photosynthetic protein complexes. It comprises a protein family that is encoded by 12 different nuclear genes in Arabidopsis. We show here that nine FtsH proteins are located in the chloroplasts. Mutations in either VAR1 or VAR2 cause typical leaf variegation and sensitivity to photoinhibition. By contrast, none of these phenotypes was observed in T-DNA insertion mutants in other ftsH genes ( ftsh1 , ftsh6 , and ftsh8 ) closely related to VAR1 and VAR2 . This finding suggests that VAR1 and VAR2 play a predominant role in the photosystem II repair cycle in thylakoid membranes. By generating VAR1-and VAR2-specific antibodies, we found that loss of either VAR1 or VAR2 results in the decreased accumulation of the other. Thus, the genetic nonredundancy between VAR1 and VAR2 could be attributed to their coordinated regulation at the protein level. These observations led us to examine whether VAR1 and VAR2 form a complex. Sucrose density gradient and gel filtration analyses revealed a complex of ‫ف‬ 400 to 450 kD, probably representing a hexamer. Furthermore, VAR1 and VAR2 were shown to coprecipitate by immunoprecipitation using VAR1-and VAR2-specific antibodies. The majority of VAR1 appears to exist as heterocomplexes with VAR2, whereas VAR2 may be present as homocomplexes as well. Based on these results, we conclude that VAR1 and VAR2 are the major components of an FtsH complex involved in the repair of photodamaged proteins in thylakoid membranes.

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Leaf-variegated mutations and their responsible genes in Arabidopsis thaliana.

Cited by 102 publications

References 82 publications

Expression in Multigene Families. Analysis of Chloroplast and Mitochondrial Proteases

Expression in Multigene Families. Analysis of Chloroplast and Mitochondrial Proteases

The Chloroplast Triggers Developmental Reprogramming When MUTS HOMOLOG1 Is Suppressed in Plants

Coordinated Regulation and Complex Formation of YELLOW VARIEGATED1 and YELLOW VARIEGATED2, Chloroplastic FtsH Metalloproteases Involved in the Repair Cycle of Photosystem II in Arabidopsis Thylakoid Membranes

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