Limits...
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

Accumulation of SAQR (AT1G64360) mRNA.(A)SAQR expression across 956 developmental stages, environmental treatments and genetic mutations. (B)SAQR expression in leaves at different development stages. (B) Represents data within the blue square in (A). Samples were taken from leaf number #2-#12 in 17-DAI plants (the lower numbered leaves are older; Schmid et al., 2005). Leaf #7 of 17-DAI plants is divided into: 7P, proximal half, 7D distal half, and 7Pt, petiole; the distal part of the leaf contains the oldest tissue. CL, cauline leaf of 21-DAI plants; SL, senescent rosette leaf of 21-DAI plants; IN1, internode 1; IN2, internode 2. Each point on the X-axis represents SAQR expression in a given tissue sample. The Y-axis represents the normalized expression level for the SAQR gene, mean expression level for all genes across the chip is normalized to 100, as indicated by the black arrow. mRNA transcriptome profiling dataset “At956-2008” is visualized using MetaOmGraph software (http://www.metnetdb.org).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4940393&req=5

Figure 2: Accumulation of SAQR (AT1G64360) mRNA.(A)SAQR expression across 956 developmental stages, environmental treatments and genetic mutations. (B)SAQR expression in leaves at different development stages. (B) Represents data within the blue square in (A). Samples were taken from leaf number #2-#12 in 17-DAI plants (the lower numbered leaves are older; Schmid et al., 2005). Leaf #7 of 17-DAI plants is divided into: 7P, proximal half, 7D distal half, and 7Pt, petiole; the distal part of the leaf contains the oldest tissue. CL, cauline leaf of 21-DAI plants; SL, senescent rosette leaf of 21-DAI plants; IN1, internode 1; IN2, internode 2. Each point on the X-axis represents SAQR expression in a given tissue sample. The Y-axis represents the normalized expression level for the SAQR gene, mean expression level for all genes across the chip is normalized to 100, as indicated by the black arrow. mRNA transcriptome profiling dataset “At956-2008” is visualized using MetaOmGraph software (http://www.metnetdb.org).

Mentions: Our microarray experiment revealed that the SAQR transcript accumulates to >2-fold greater levels in QQS RNAi mutant compared to WT control plants, which indicates that SAQR transcript accumulation is negatively influenced by QQS. We evaluated global SAQR expression (Figure 2A) using MetaOmGraphenumfont 2 and a large public microarray dataset “At956-2008” (Li et al., 2007, 2009; Mentzen and Wurtele, 2008). Under standard growth conditions in WT plants, as shown in Figure 2A, SAQR expression is highest in fully expanded leaves, at the base of the mature inflorescence, in senescing leaves, and cauline leaves. Expression is moderate within the hypocotyl and the plant rosette prior to flowering. SAQR accumulation is below detection limits in the roots, developing fruits, and very young seedlings and seeds.


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)

Accumulation of SAQR (AT1G64360) mRNA.(A)SAQR expression across 956 developmental stages, environmental treatments and genetic mutations. (B)SAQR expression in leaves at different development stages. (B) Represents data within the blue square in (A). Samples were taken from leaf number #2-#12 in 17-DAI plants (the lower numbered leaves are older; Schmid et al., 2005). Leaf #7 of 17-DAI plants is divided into: 7P, proximal half, 7D distal half, and 7Pt, petiole; the distal part of the leaf contains the oldest tissue. CL, cauline leaf of 21-DAI plants; SL, senescent rosette leaf of 21-DAI plants; IN1, internode 1; IN2, internode 2. Each point on the X-axis represents SAQR expression in a given tissue sample. The Y-axis represents the normalized expression level for the SAQR gene, mean expression level for all genes across the chip is normalized to 100, as indicated by the black arrow. mRNA transcriptome profiling dataset “At956-2008” is visualized using MetaOmGraph software (http://www.metnetdb.org).
© Copyright Policy
Related In: Results  -  Collection

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

Figure 2: Accumulation of SAQR (AT1G64360) mRNA.(A)SAQR expression across 956 developmental stages, environmental treatments and genetic mutations. (B)SAQR expression in leaves at different development stages. (B) Represents data within the blue square in (A). Samples were taken from leaf number #2-#12 in 17-DAI plants (the lower numbered leaves are older; Schmid et al., 2005). Leaf #7 of 17-DAI plants is divided into: 7P, proximal half, 7D distal half, and 7Pt, petiole; the distal part of the leaf contains the oldest tissue. CL, cauline leaf of 21-DAI plants; SL, senescent rosette leaf of 21-DAI plants; IN1, internode 1; IN2, internode 2. Each point on the X-axis represents SAQR expression in a given tissue sample. The Y-axis represents the normalized expression level for the SAQR gene, mean expression level for all genes across the chip is normalized to 100, as indicated by the black arrow. mRNA transcriptome profiling dataset “At956-2008” is visualized using MetaOmGraph software (http://www.metnetdb.org).
Mentions: Our microarray experiment revealed that the SAQR transcript accumulates to >2-fold greater levels in QQS RNAi mutant compared to WT control plants, which indicates that SAQR transcript accumulation is negatively influenced by QQS. We evaluated global SAQR expression (Figure 2A) using MetaOmGraphenumfont 2 and a large public microarray dataset “At956-2008” (Li et al., 2007, 2009; Mentzen and Wurtele, 2008). Under standard growth conditions in WT plants, as shown in Figure 2A, SAQR expression is highest in fully expanded leaves, at the base of the mature inflorescence, in senescing leaves, and cauline leaves. Expression is moderate within the hypocotyl and the plant rosette prior to flowering. SAQR accumulation is below detection limits in the roots, developing fruits, and very young seedlings and seeds.

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