Surabhi, Giridara-Kumar , Sanjay, Kumar , Dan, DeLaughter , Katie, Clowers , Alam, Nausheen , Loretta, Johnson , Shah, Jyoti .
Environmental and ecological controls on gene expression of root processes in prairie plants.
Grasslands cover 1/3 of the US. Tall grass prairie is amongst the most productive. Thus, we must understand how grasses respond to perturbations in limiting factors such as nitrogen (N) and water. Despite the contribution of roots to productivity, the response of roots to stress has largely been ignored. We propose genomic approaches to identify genes that are differentially expressed in the roots of the dominant big bluestem (Andropogon gerardii) in response to N. Our objectives are to conduct genome-wide expression analyses in field-grown plants in experimental plots at Konza Prairie and correlate gene expression with growth, ecological response, and metabolites. We took advantage of genomics resources available for Zea mays, a close relative of big bluestem. We used Iowa State’s Zea EST spotted array for cross-species hybridization with big bluestem root cDNA. 60% of big bluestem cDNA hybridized to the 19,200 Zea mays features. We identified 570 genes that showed statistically significant hybridization. Of the 570 genes, 140 were significantly up-regulated and 186 were down-regulated (2-fold or more) in response to high N. Genes that were down-regulated include transcription factors (5.8%), signaling genes (4.3%) and regulatory genes 14-3-3 (3.6%). 14-3-3 helps to regulate carbohydrate and N metabolism. Genes that were up-regulated in response to high N include transcription factors, those involved in defense/ stress responses and in growth regulation (e.g. putative auxin-regulated protein). Several other genes (root hair less1 and transporters) were also up-regulated. Detailed functional categorization of differentially expressed genes in relation to root and shoot ecological and physiological responses to N and water are underway.
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1 - Kansas State University, Division of Biology, Ackert Hall, Rm 309, Manhattan, KS, 66506, USA
2 - Kansas State University, Division of Biology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM