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Winter wheat genotypes under different levels of nitrogen and water stress: Changes in grain protein composition

Quantification of Bt Delta-endotoxins in leaf tissues of tropical Bt maize populations

Author: Saint Pierre, C.
Author: Peterson, C.J.
Author: Ross, A.S.
Author: Ohm, J.B.
Author: Verhoeven, M.C.
Author: Larson, M.
Author: Hoefer, B.
Author: Murenga, M.
Author: Danson, J.
Author: Mugo, S.
Author: Githiri, S.M.
Author: Wanjala, B.
Year: 2008
Year: 2012
ISSN: 0733-5210
URI: http://hdl.handle.net/10883/3195
Abstract: Hard white winter wheat with superior and consistent quality is preferable for Asian markets. This study investigated the combined influences of moisture deficit during grain-fill and N management on protein quality, dough rheological properties, and protein molecular weight distributions in soft and hard winter wheats. Genotypes were grown under an irrigation gradient and two N-fertilization levels. Grain polyphenol oxidase (PPO) activity, SDS sedimentation, and Mixograph analyses were evaluated. Flour protein composition was characterized using SE-HPLC. Moisture stress during grain-fill increased flour protein content. N fertilization increased flour protein content. No significant correlation was found between flour protein and PPO. Changes in protein composition were related to general increases in protein content, regardless if the result of reduced irrigation or increased fertilization rate. The percentage of monomeric proteins increased more than the polymeric proteins as flour protein increased. Similarly, SDS sedimentation volume increased as a function of protein content. As expected, subunit GluD1 5+10 was associated with larger sedimentation volume and higher dough strength in genotypes as compared to those with subunit GluD1 2+12. Biplot analyses showed that genotypes of similar protein quality and composition responded similarly to N and irrigation treatments.
Abstract: In Kenya, stem borers destroy an estimated 13.5% of farmers' annual maize harvest. Maize transformed using Bacillus thuringiensis (Bt) derived genes controls stem borers without negative effects to humans, livestock or the environment. The effectiveness and sustainability of Bt transgenic technology in the control of stem borers depends on the levels of concentration of the Bt ä-endotoxins in plant tissues. Kenya introduced Bt maize events to test the efficacy of Bt maize in controlling stem borers, and to develop high-yielding and locally adapted Bt maize germplasm for farmers. The objective of this study was to assess under greenhouse conditions the concentration levels of Bt ä-endotoxins in the leaf tissues of the parents, the F1, and the F2:3 populations of tropical maize, as a measure of stability and sustainability. Kenya introduced Bt maize events to test the efficacy of Bt maize in controlling stem borers, and to develop high-yielding and locally adapted Bt maize germplasm for farmers. The objective of this study was to assess under greenhouse conditions the concentration levels of Bt ä-endotoxins in the leaf tissues of the parents, the F1, and the F2:3 populations of tropical maize, as a measure of stability and sustainability. Two public Bt maize lines (Event 216 and Event 223) containing the cry1Ab::ubi gene were crossed with two non-Bt maize inbred lines, CML144 and CML159, to assess how the concentrations of Bt ä-endotoxins are transmitted from parents to F1 and to F2 generations. The mean concentration of Bt ä-endotoxins (ìg/g) was 4.93 and 4.63 in Events 216 and 223 respectively. As expected, F1 generations of all the crosses had similar concentrations of Bt ä-endotoxins. However, the F2 generations showed a spread of concentrations. These findings may imply that genotypes with a higher mean concentration of Bt ä-endotoxins also have a lower level of plant damage traits expressed. In addition, these observations indicate that the cry1Ab gene was dominant and was inherited following the Mendelian segregation and that Events 216 and 223 could be utilized as reliable sources of resistance to stem borers in maize breeding programmes.
Language: English
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Type: Article
Country focus: Kenya
Region: Global
Region: Eastern Africa
Pages: 407-416
Pages: 11181-11186
Issue: 3
Issue: 51
Journal: Journal of Cereal Science
Journal: African Journal of Biotechnology
Volume: 47
Volume: 11
DOI: 10.1016/j.jcs.2007.05.007
DOI: 10.5897/AJB11.3433
Keywords: Hard white wheat
Keywords: Grain protein
Keywords: SE-HPLC
Keywords: Stress
Keywords: Bt maize
Keywords: stem borers
Keywords: Bt delta-endotoxins
Keywords: enzyme-linked immunosorbent assay (ELISA)
Keywords: Dot Blot Analysis
Keywords: Cry1Ab
Publisher URI: http://www.sciencedirect.com/science/article/pii/S0733521007000902
Access Level: Restricted Access


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  • Maize
    Maize breeding, phytopathology, entomology, physiology, quality, and biotech

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