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The resemblance and disparity of gene expression in dormant and non-dormant seeds and crown buds of leafy spurge (Euphorbia esula).

Chao WS, Doğramaci M, Anderson JV, Foley ME, Horvath DP - BMC Plant Biol. (2014)

Bottom Line: Thus, we compared various phases of dormancy between seeds and buds to identify common genes and molecular processes, which should provide new insights about common regulators of dormancy.Cluster analysis of expression profiles for 201 selected genes indicated bud and seed samples clustered separately.Combined results indicate that common molecular mechanisms associated with dormancy transitions of buds and seeds involve processes associated with ABA and auxin signaling and transport, cell cycle, and AP2/ERF transcription factors or their up-stream regulators.

View Article: PubMed Central - PubMed

Affiliation: USDA-Agricultural Research Service, Biosciences Research Lab, Sunflower and Plant Biology Research Unit, 1605 Albrecht Boulevard N, Fargo 58102, ND, USA. wun.chao@ars.usda.gov.

ABSTRACT

Background: Leafy spurge (Euphorbia esula L.) is a herbaceous perennial weed and dormancy in both buds and seeds is an important survival mechanism. Bud dormancy in leafy spurge exhibits three well-defined phases of para-, endo- and ecodormancy; however, seed dormancy for leafy spurge is classified as physiological dormancy that requires after-ripening and alternating temperature for maximal germination. Overlaps in transcriptome profiles between different phases of bud and seed dormancy have not been determined. Thus, we compared various phases of dormancy between seeds and buds to identify common genes and molecular processes, which should provide new insights about common regulators of dormancy.

Results: Cluster analysis of expression profiles for 201 selected genes indicated bud and seed samples clustered separately. Direct comparisons between buds and seeds are additionally complicated since seeds incubated at a constant temperature of 20°C for 21 days (21d C) could be considered paradormant (Para) because seeds may be inhibited by endosperm-generated signals, or ecodormant (Eco) because seeds germinate after being subjected to alternating temperature of 20:30°C. Since direct comparisons in gene expression between buds and seeds were problematic, we instead examined commonalities in differentially-expressed genes associated with different phases of dormancy. Comparison between buds and seeds ('Para to Endo buds' and '21d C to 1d C seeds'), using endodormant buds (Endo) and dormant seeds (1d C) as common baselines, identified transcripts associated with cell cycle (HisH4), stress response/transcription factors (ICE2, ERFB4/ABR1), ABA and auxin response (ABA1, ARF1, IAA7, TFL1), carbohydrate/protein degradation (GAPDH_1), and transport (ABCB2). Comparison of transcript abundance for the 'Eco to Endo buds' and '21d C to 1d C seeds' identified transcripts associated with ABA response (ATEM6), auxin response (ARF1), and cell cycle (HisH4). These results indicate that the physiological state of 21d C seeds is more analogous to paradormant buds than that of ecodormant buds.

Conclusion: Combined results indicate that common molecular mechanisms associated with dormancy transitions of buds and seeds involve processes associated with ABA and auxin signaling and transport, cell cycle, and AP2/ERF transcription factors or their up-stream regulators.

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Treatments abbreviations and seed status for qRT-PCR analysis.
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Fig3: Treatments abbreviations and seed status for qRT-PCR analysis.

Mentions: Cluster analysis on the expression profiles of 201 genes (Additional file 1: Table S1) indicated that buds and seeds fell into two main groups (Figure 1). One group contained all bud samples (Figure 2); Eco, Endo, Para, and 2d-growth (after paradormancy release). The second group contained all seed samples (Figure 3); 1d C (dormant), 21d C + 2d A (germinating), and 21d C (germination competent but inhibited by environmental or physiological signals). Even though buds and seeds clustered separately (Figure 1), it is possible that common physiological processes associated with dormancy states exist between them. For example, although 2d-growth and 21d C + 2d A both contained growing meristems, this similarity did not make these two samples cluster together.Figure 1


The resemblance and disparity of gene expression in dormant and non-dormant seeds and crown buds of leafy spurge (Euphorbia esula).

Chao WS, Doğramaci M, Anderson JV, Foley ME, Horvath DP - BMC Plant Biol. (2014)

Treatments abbreviations and seed status for qRT-PCR analysis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4256794&req=5

Fig3: Treatments abbreviations and seed status for qRT-PCR analysis.
Mentions: Cluster analysis on the expression profiles of 201 genes (Additional file 1: Table S1) indicated that buds and seeds fell into two main groups (Figure 1). One group contained all bud samples (Figure 2); Eco, Endo, Para, and 2d-growth (after paradormancy release). The second group contained all seed samples (Figure 3); 1d C (dormant), 21d C + 2d A (germinating), and 21d C (germination competent but inhibited by environmental or physiological signals). Even though buds and seeds clustered separately (Figure 1), it is possible that common physiological processes associated with dormancy states exist between them. For example, although 2d-growth and 21d C + 2d A both contained growing meristems, this similarity did not make these two samples cluster together.Figure 1

Bottom Line: Thus, we compared various phases of dormancy between seeds and buds to identify common genes and molecular processes, which should provide new insights about common regulators of dormancy.Cluster analysis of expression profiles for 201 selected genes indicated bud and seed samples clustered separately.Combined results indicate that common molecular mechanisms associated with dormancy transitions of buds and seeds involve processes associated with ABA and auxin signaling and transport, cell cycle, and AP2/ERF transcription factors or their up-stream regulators.

View Article: PubMed Central - PubMed

Affiliation: USDA-Agricultural Research Service, Biosciences Research Lab, Sunflower and Plant Biology Research Unit, 1605 Albrecht Boulevard N, Fargo 58102, ND, USA. wun.chao@ars.usda.gov.

ABSTRACT

Background: Leafy spurge (Euphorbia esula L.) is a herbaceous perennial weed and dormancy in both buds and seeds is an important survival mechanism. Bud dormancy in leafy spurge exhibits three well-defined phases of para-, endo- and ecodormancy; however, seed dormancy for leafy spurge is classified as physiological dormancy that requires after-ripening and alternating temperature for maximal germination. Overlaps in transcriptome profiles between different phases of bud and seed dormancy have not been determined. Thus, we compared various phases of dormancy between seeds and buds to identify common genes and molecular processes, which should provide new insights about common regulators of dormancy.

Results: Cluster analysis of expression profiles for 201 selected genes indicated bud and seed samples clustered separately. Direct comparisons between buds and seeds are additionally complicated since seeds incubated at a constant temperature of 20°C for 21 days (21d C) could be considered paradormant (Para) because seeds may be inhibited by endosperm-generated signals, or ecodormant (Eco) because seeds germinate after being subjected to alternating temperature of 20:30°C. Since direct comparisons in gene expression between buds and seeds were problematic, we instead examined commonalities in differentially-expressed genes associated with different phases of dormancy. Comparison between buds and seeds ('Para to Endo buds' and '21d C to 1d C seeds'), using endodormant buds (Endo) and dormant seeds (1d C) as common baselines, identified transcripts associated with cell cycle (HisH4), stress response/transcription factors (ICE2, ERFB4/ABR1), ABA and auxin response (ABA1, ARF1, IAA7, TFL1), carbohydrate/protein degradation (GAPDH_1), and transport (ABCB2). Comparison of transcript abundance for the 'Eco to Endo buds' and '21d C to 1d C seeds' identified transcripts associated with ABA response (ATEM6), auxin response (ARF1), and cell cycle (HisH4). These results indicate that the physiological state of 21d C seeds is more analogous to paradormant buds than that of ecodormant buds.

Conclusion: Combined results indicate that common molecular mechanisms associated with dormancy transitions of buds and seeds involve processes associated with ABA and auxin signaling and transport, cell cycle, and AP2/ERF transcription factors or their up-stream regulators.

Show MeSH
Related in: MedlinePlus