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A Clade-Specific Arabidopsis Gene Connects Primary Metabolism and Senescence.

Jones DC, Zheng W, Huang S, Du C, Zhao X, Yennamalli RM, Sen TZ, Nettleton D, Wurtele ES, Li L - Front Plant Sci (2016)

Bottom Line: In contrast, under experimentally induced senescence, SAQR expression increases in vasculature of cotyledons but not in true leaves.In SAQR KO line, the transcript level of the dirigent-like disease resistance gene (AT1G22900) is increased, while that of the Early Light Induced Protein 1 gene (ELIP1, AT3G22840) is decreased.Taken together, these data indicate that SAQR may function in the QQS network, playing a role in integration of primary metabolism with adaptation to internal and environmental changes, specifically those that affect the process of senescence.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Development and Cell Biology, Iowa State University, Ames IA, USA.

ABSTRACT
Nearly immobile, plants have evolved new components to be able to respond to changing environments. One example is Qua Quine Starch (QQS, AT3G30720), an Arabidopsis thaliana-specific orphan gene that integrates primary metabolism with adaptation to environment changes. SAQR (Senescence-Associated and QQS-Related, AT1G64360), is unique to a clade within the family Brassicaceae; as such, the gene may have arisen about 20 million years ago. SAQR is up-regulated in QQS RNAi mutant and in the apx1 mutant under light-induced oxidative stress. SAQR plays a role in carbon allocation: overexpression lines of SAQR have significantly decreased starch content; conversely, in a saqr T-DNA knockout (KO) line, starch accumulation is increased. Meta-analysis of public microarray data indicates that SAQR expression is correlated with expression of a subset of genes involved in senescence, defense, and stress responses. SAQR promoter::GUS expression analysis reveals that SAQR expression increases after leaf expansion and photosynthetic capacity have peaked, just prior to visible natural senescence. SAQR is expressed predominantly within leaf and cotyledon vasculature, increasing in intensity as natural senescence continues, and then decreasing prior to death. In contrast, under experimentally induced senescence, SAQR expression increases in vasculature of cotyledons but not in true leaves. In SAQR KO line, the transcript level of the dirigent-like disease resistance gene (AT1G22900) is increased, while that of the Early Light Induced Protein 1 gene (ELIP1, AT3G22840) is decreased. Taken together, these data indicate that SAQR may function in the QQS network, playing a role in integration of primary metabolism with adaptation to internal and environmental changes, specifically those that affect the process of senescence.

No MeSH data available.


Related in: MedlinePlus

Senescence-Associated and QQS-Related (SAQR) gene and predicted protein.(A)SAQR has homologs in a monophyletic group within family Brassicaceae. Blast searches of the NCBI database show three genera contain a SAQR homolog: Arabidopsis, Capsella, and Boechera. Blue font, genomes containing an SAQR homolog. Underlined names, species with sequenced genomes. Green lines, the monophyletic group containing SAQR. Simplified tree structure adapted from Koch and Kiefer (2005), Clauss and Koch (2006), Schranz et al. (2006), Windsor et al. (2006). (B)SAQR gene model, as determined by 5′ and 3′ RACE. Black boxes, 5′ and 3′ UTR; lined gray box, coding region; black line, intron; gray line, non-transcribed region. Constructs used to make the SAQR promoter-GUS and SAQR-OE lines are pictured in relation to the gene model. The BAR, 35S, and GUS/GFP reporter are not to scale. Nucleotide positions numbered in relation to the ATG start codon of SAQR. (C) Structural models of the SAQR protein predicted using I-TASSER. Helices are colored red; sheets, yellow; loops, green. Image made using PyMol (DeLano and Bromberg, 2002).
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Figure 1: Senescence-Associated and QQS-Related (SAQR) gene and predicted protein.(A)SAQR has homologs in a monophyletic group within family Brassicaceae. Blast searches of the NCBI database show three genera contain a SAQR homolog: Arabidopsis, Capsella, and Boechera. Blue font, genomes containing an SAQR homolog. Underlined names, species with sequenced genomes. Green lines, the monophyletic group containing SAQR. Simplified tree structure adapted from Koch and Kiefer (2005), Clauss and Koch (2006), Schranz et al. (2006), Windsor et al. (2006). (B)SAQR gene model, as determined by 5′ and 3′ RACE. Black boxes, 5′ and 3′ UTR; lined gray box, coding region; black line, intron; gray line, non-transcribed region. Constructs used to make the SAQR promoter-GUS and SAQR-OE lines are pictured in relation to the gene model. The BAR, 35S, and GUS/GFP reporter are not to scale. Nucleotide positions numbered in relation to the ATG start codon of SAQR. (C) Structural models of the SAQR protein predicted using I-TASSER. Helices are colored red; sheets, yellow; loops, green. Image made using PyMol (DeLano and Bromberg, 2002).

Mentions: The six species that possess a SAQR homolog belong to a lineage of organisms that separated from the lineage containing the Brassica and Eutrema genera about 20 million years ago (MYA; Clauss and Koch, 2006; Domazet-Lošo et al., 2007; Arendsee et al., 2014). The monophyletic group that contains these six species also includes the genera Turritis, Olimarabidopsis, Halimolobus, and Crucihimalaya (Figure 1A). It is possible that these genera also contain a SAQR homolog, but full genomes of members of these genera were not publicly available as of June 12, 2016.


A Clade-Specific Arabidopsis Gene Connects Primary Metabolism and Senescence.

Jones DC, Zheng W, Huang S, Du C, Zhao X, Yennamalli RM, Sen TZ, Nettleton D, Wurtele ES, Li L - Front Plant Sci (2016)

Senescence-Associated and QQS-Related (SAQR) gene and predicted protein.(A)SAQR has homologs in a monophyletic group within family Brassicaceae. Blast searches of the NCBI database show three genera contain a SAQR homolog: Arabidopsis, Capsella, and Boechera. Blue font, genomes containing an SAQR homolog. Underlined names, species with sequenced genomes. Green lines, the monophyletic group containing SAQR. Simplified tree structure adapted from Koch and Kiefer (2005), Clauss and Koch (2006), Schranz et al. (2006), Windsor et al. (2006). (B)SAQR gene model, as determined by 5′ and 3′ RACE. Black boxes, 5′ and 3′ UTR; lined gray box, coding region; black line, intron; gray line, non-transcribed region. Constructs used to make the SAQR promoter-GUS and SAQR-OE lines are pictured in relation to the gene model. The BAR, 35S, and GUS/GFP reporter are not to scale. Nucleotide positions numbered in relation to the ATG start codon of SAQR. (C) Structural models of the SAQR protein predicted using I-TASSER. Helices are colored red; sheets, yellow; loops, green. Image made using PyMol (DeLano and Bromberg, 2002).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4940393&req=5

Figure 1: Senescence-Associated and QQS-Related (SAQR) gene and predicted protein.(A)SAQR has homologs in a monophyletic group within family Brassicaceae. Blast searches of the NCBI database show three genera contain a SAQR homolog: Arabidopsis, Capsella, and Boechera. Blue font, genomes containing an SAQR homolog. Underlined names, species with sequenced genomes. Green lines, the monophyletic group containing SAQR. Simplified tree structure adapted from Koch and Kiefer (2005), Clauss and Koch (2006), Schranz et al. (2006), Windsor et al. (2006). (B)SAQR gene model, as determined by 5′ and 3′ RACE. Black boxes, 5′ and 3′ UTR; lined gray box, coding region; black line, intron; gray line, non-transcribed region. Constructs used to make the SAQR promoter-GUS and SAQR-OE lines are pictured in relation to the gene model. The BAR, 35S, and GUS/GFP reporter are not to scale. Nucleotide positions numbered in relation to the ATG start codon of SAQR. (C) Structural models of the SAQR protein predicted using I-TASSER. Helices are colored red; sheets, yellow; loops, green. Image made using PyMol (DeLano and Bromberg, 2002).
Mentions: The six species that possess a SAQR homolog belong to a lineage of organisms that separated from the lineage containing the Brassica and Eutrema genera about 20 million years ago (MYA; Clauss and Koch, 2006; Domazet-Lošo et al., 2007; Arendsee et al., 2014). The monophyletic group that contains these six species also includes the genera Turritis, Olimarabidopsis, Halimolobus, and Crucihimalaya (Figure 1A). It is possible that these genera also contain a SAQR homolog, but full genomes of members of these genera were not publicly available as of June 12, 2016.

Bottom Line: In contrast, under experimentally induced senescence, SAQR expression increases in vasculature of cotyledons but not in true leaves.In SAQR KO line, the transcript level of the dirigent-like disease resistance gene (AT1G22900) is increased, while that of the Early Light Induced Protein 1 gene (ELIP1, AT3G22840) is decreased.Taken together, these data indicate that SAQR may function in the QQS network, playing a role in integration of primary metabolism with adaptation to internal and environmental changes, specifically those that affect the process of senescence.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Development and Cell Biology, Iowa State University, Ames IA, USA.

ABSTRACT
Nearly immobile, plants have evolved new components to be able to respond to changing environments. One example is Qua Quine Starch (QQS, AT3G30720), an Arabidopsis thaliana-specific orphan gene that integrates primary metabolism with adaptation to environment changes. SAQR (Senescence-Associated and QQS-Related, AT1G64360), is unique to a clade within the family Brassicaceae; as such, the gene may have arisen about 20 million years ago. SAQR is up-regulated in QQS RNAi mutant and in the apx1 mutant under light-induced oxidative stress. SAQR plays a role in carbon allocation: overexpression lines of SAQR have significantly decreased starch content; conversely, in a saqr T-DNA knockout (KO) line, starch accumulation is increased. Meta-analysis of public microarray data indicates that SAQR expression is correlated with expression of a subset of genes involved in senescence, defense, and stress responses. SAQR promoter::GUS expression analysis reveals that SAQR expression increases after leaf expansion and photosynthetic capacity have peaked, just prior to visible natural senescence. SAQR is expressed predominantly within leaf and cotyledon vasculature, increasing in intensity as natural senescence continues, and then decreasing prior to death. In contrast, under experimentally induced senescence, SAQR expression increases in vasculature of cotyledons but not in true leaves. In SAQR KO line, the transcript level of the dirigent-like disease resistance gene (AT1G22900) is increased, while that of the Early Light Induced Protein 1 gene (ELIP1, AT3G22840) is decreased. Taken together, these data indicate that SAQR may function in the QQS network, playing a role in integration of primary metabolism with adaptation to internal and environmental changes, specifically those that affect the process of senescence.

No MeSH data available.


Related in: MedlinePlus