Improvement of abiotic stress tolerance and calcium-deficiency disorder resistance of tomato plants

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Show simple item record Wu, Qingyu 2012-07-16T16:24:45Z 2012-07-16T16:24:45Z 2012-07-16
dc.description.abstract Plants are continuously exposed to numerous abiotic stresses, which adversely affect plant growth, development, and yield. Plants have developed different signaling pathways to cope with abiotic stresses, and some of the pathways converge to help plants tolerate simultaneous stresses. Here, we report ectopic expression of an Arabidopsis glutaredoxin AtGRXS17 that confers tolerance to multiple abiotic stresses in tomato plants. In yeast assays, AtGRXS17 co-localized with yeast ScGrx3 in the nucleus and suppressed the sensitivity of yeast grx3grx4 double mutants to oxidative stress and heat shock. In plants, GFP-AtGRXS17 fusion proteins initially localized in the cytoplasm but migrated to the nucleus during heat stress. Ectopic expression of AtGRXS17 in tomato plants minimized photo-oxidation of chlorophyll and reduced oxidative damage of cell membrane systems under heat stress. Furthermore, expression of the heat shock transcription factor (HSF) and heat shock protein (HSP) genes was up-regulated in AtGRXS17-expressing tomato plants during heat stress when compared to wild-type controls. Under cold, drought, and oxidative stress conditions, AtGRXS17-expressing tomato plants also displayed more vigorous growth and less physiological damage than those of the wild-type control plants. Quantitative real-time PCR (qRT-PCR) analysis indicated that expression of AtGRXS17 alters multiple stress defense signaling pathways, including the Abscisic Acid (ABA) and C-Repeat Binding Factors (CBF) pathways. The results revealed a conserved function for a glutaredoxin protein in abiotic stress adaptation, and manipulation of AtGRXS17 may be a useful approach to improve crop stress tolerance and understand plant signaling under abiotic stress conditions. Deregulated expression of an Arabidopsis H[superscript]+/Ca[superscript]2[superscript]+ antiporter (sCAX1) in agricultural crops increases total calcium (Ca[superscript]2[superscript]+) but may result in yield loses due to calcium-deficiency like symptoms. Here we demonstrate that co-expression of a maize calreticulin (CRT, a Ca[superscript]2[superscript]+ binding protein located at endoplasmic reticulum) in sCAX1-expressing plants mitigated these adverse effects while maintaining enhanced Ca[superscript]2[superscript]+ content. Co-expression of CRT and sCAX1 could alleviate the hypersensitivity to ion imbalance in tobacco plants. Furthermore, blossom-end rot (BER) in tomato may be linked to changes in CAX activity and enhanced CRT expression mitigated BER in sCAX1 expressing lines. These findings suggest that co-expressing Ca[superscript]2[superscript]+ transporters and binding protein at different intracellular compartments can alter the content and distribution of calcium within the plant matrix. en_US
dc.description.sponsorship Kansas State University AES project (NAHF381121), HI Green System, United States Department of Agriculture Agriculture and Food Research Initiative (#2010-65108-20538), and National Horticultural Research Inistitute Rural Development Administration-Kansas State University Cooperative Research Project en_US
dc.language.iso en_US en_US
dc.publisher Kansas State University en
dc.subject GRX en_US
dc.subject Genetic engineering en_US
dc.subject ROS en_US
dc.subject Abiotic stress en_US
dc.title Improvement of abiotic stress tolerance and calcium-deficiency disorder resistance of tomato plants en_US
dc.type Dissertation en_US Doctor of Philosophy en_US
dc.description.level Doctoral en_US
dc.description.department Department of Horticulture, Forestry, and Recreation Resources en_US
dc.description.advisor Sunghun Park en_US
dc.subject.umi Biology, Plant Physiology (0817) en_US
dc.subject.umi Horticulture (0471) en_US 2012 en_US August en_US

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