Location: Sunflower and Plant Biology ResearchTitle: Auxin and ABA act as central regulators of developmental networks associated with paradormancy in Canada thistle (Cirsium arvense)) Author
Submitted to: Functional and Integrative Genomics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/25/2012
Publication Date: 9/1/2012
Citation: Anderson, J.V., Dogramaci, M., Horvath, D.P., Foley, M.E., Chao, W.S., Suttle, J.C., Thimmapuram, J., Hernandez, A.G., Ali, S., Mikel, M.A. 2012. Auxin and ABA act as central regulators of developmental networks associated with paradormancy in Canada thistle (Cirsium arvense). Functional and Integrative Genomics. 12(3):515-531. Interpretive Summary: Farmers, ranchers, and land managers are required by law to control noxious perennial weeds, and existing control measures are often expensive or impracticable, especially in organic production systems. Perennial weeds such as Canada thistle spread and persist, in part, because they reproduce vegetatively from hundreds of buds on the root system. Paradormancy or quiescence of root bud on intact plants prevents growth and is a key reason for poor control by conventional measures. To assist in development of more effective and next generation weed management strategies, we focused on elucidating global patterns of gene expression involved in the maintenance and release of paradormancy in root buds of Canada thistle. Using next generation DNA sequencing technologies, we identified about 13,000 genes. Data analyses highlighted the role of many genes in interconnected plant hormone signalling networks as well as other critical plant growth processes. This research sets the stage to examine the role of plant hormones like abscisic acid, gibberellic acid, and auxin in paradormancy maintenance and release.
Technical Abstract: Dormancy in underground vegetative buds of Canada thistle, an herbaceous perennial weed, allows escape from current control methods and contributes to its invasive nature. In this study, ~65% of root sections obtained from greenhouse propagated Canada thistle produced new vegetative shoots by 14 d post-sectioning. RNA samples obtained from sectioned roots incubated 0, 24, 48, and 72 h at 25oC under 16:8 h light:dark conditions were used to construct four MID-tagged cDNA libraries. Analysis of in silico data obtained using 454 pyrosequencing technologies identified molecular networks associated with paradormancy release in underground vegetative buds of Canada thistle. Sequencing of two replicate plates produced ~2.5 million ESTs with an average read length of 362 bases. These ESTs assembled into 67358 unique sequences (21777 contigs & 45581 singlets) and annotation against the arabidopsis database identified 15232 unigenes. Gene Set Enrichment Analysis (GSEA) indicated that putative Arabidopsis homologues involved in mitochondrial transport, protein ubiquination, hormone signalling (ABA, JA, SA), and stress response were among the over-represented (p<0.05) and rapidly down-regulated transcripts in sectioned roots, while cell redox homeostasis, hormone signalling (ethylene, GA), photosynthetic processes, DNA replication and transcription, methionine salvage, TCA and glycoxylate cycle were over-represented among the many up-regulated transcripts during paradormancy release. A model based on our data suggests that ABA synthesis/signaling is a key regulator of paradormancy in underground adventitious buds of Canada thistle and is regulated through the response of FUS3 to polar auxin transport. The model further proposes that GA signaling, through interactions with ABA/FUS3 is required for induction of cell division and vegetative outgrowth.