Yamaguchi, Mineo , Valliyodan, Babu , Zhang, Juan , LeNoble, Mary , Yu, Oliver , Nguyen, Henry , Sharp, Robert .
Proteomic analysis of the differential responses of elongation rate to water deficit within the soybean primary root growth zone.
Roots can continue elongation at low water potentials that completely inhibit shoot growth. Our research on root growth regulation takes advantage of a kinematic approach; in both maize and soybean primary roots results show that cell elongation under water deficits is maintained preferentially towards the apex. In the apical 4 mm (region 1) of soybean roots, elongation is maintained at well-watered rates under severe water deficits (water potential of -1.6 MPa), whereas in the 4-8 mm region (region 2), which exhibits maximum elongation in well-watered roots, elongation is progressively inhibited under water deficits. The objective of this study is to gain a comprehensive understanding of how protein composition changes in response to water deficits in the different regions. As an initial step, total soluble protein profiles were analyzed by 2DE and mass spectrometry. Twenty and 23 differentially expressed proteins were identified in regions 1 and 2, respectively; 17 were common to both regions. The functional roles of these proteins in stress response will be discussed. In particular, the identity of several up-regulated proteins indicates that protection from oxidative damage is likely to be of particular importance for the maintenance of elongation in region 1 under water deficits. These proteins include ferritin, which suppresses the generation of hydroxyl radicals by sequestering free iron, and several enzymes related to biosynthesis of isoflavonoids, which can serve as ROS scavengers. HPLC analysis confirmed a substantial increase of isoflavonoid content in region 1 of water-stressed compared to well-watered roots. (Supported by a grant from Monsanto/University of Missouri-Columbia.)
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1 - University of Missouri-Columbia, Division of Plant Sciences, 1-31 Agriculture Building, Columbia, MO, 65211, USA
2 - University of Missouri-Columbia, Division of Plant Sciences
3 - Donald Danforth Plant Science Center
reactive oxygen species
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM