Bashir, Anbreen , Leverich, Wesley J. .
Fitness Responses to Water-Deficit Stress in GM Rice, Oryza rufipogon, and F1 plants.
As part of a broader collaborative study to measure and assess the effects of possible gene flow between cultivated rice and its wild progenitor (Oryza rufipogon), we have been studying the relative fitnesses of genetically modified rice cultivars, the wild ancestor of cultivated rice, O. rufipogon, and their F1 hybrids. The GM rice lines in our studies contain a LEA (late embryogenesis abundant) protein, HVA1 with a strong constitutive promoter, rice act 1(Actin 1). These lines, from David Ho's lab, exhibit increased tolerance to water-deficit stress. In earlier studies, we estimated relative fitnesses of 4 GM rice lines, O. rufipogon, and 4 F1 hybrid lines. The study reported here examines the relative response to water-deficit stress challenge in these same lines. Beginning on the tenth day following planting, water was withheld for 5 days; after two days of watering, water was again withheld for 5 days. Plants were then maintained with normal amounts of water for the remainder of the study. Fitness responses to the water-deficit stress treatment will be assessed by measuring number of leaves, number of tillers, day of first flowering, number of panicles, reproductive biomass, final plant height, and total plant biomass. We will assess the variation between unstressed and water-deficit stressed treatment, as well as differences between GM lines, wild rice, and F1 lines. Preliminary data suggest that more tillers may be produced under water-deficit stress. Also, initiation of flowering in F1 plants is delayed relative to both GM and O. rufipogon parental lines. The data suggest that there may be fitness differences among the treatment groups in response to water-deficit stress.
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1 - Saint Louis University, Department of Biology, 3507 Laclede Avenue, St Louis, Missouri, 63103-2010, USA
Presentation Type: Poster
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM