Cytokinin-mediated source/sink modifications improve drought tolerance and increase grain yield in rice under water-stress.
Plant Biotechnol J, 2011/9;9(7):747-58.
Peleg Z[1], Reguera M, Tumimbang E, Walia H, Blumwald E
Affiliations
PMID: 21284800DOI: 10.1111/j.1467-7652.2010.00584.x
Impact factor: 13.263
Abstract
Drought is the major environmental factor limiting crop productivity worldwide. We hypothesized that it is possible to enhance drought tolerance by delaying stress-induced senescence through the stress-induced synthesis of cytokinins in crop-plants. We generated transgenic rice (Oryza sativa) plants expressing an isopentenyltransferase (IPT) gene driven by P(SARK) , a stress- and maturation-induced promoter. Plants were tested for drought tolerance at two yield-sensitive developmental stages: pre- and post-anthesis. Under both treatments, the transgenic rice plants exhibited delayed response to stress with significantly higher grain yield (GY) when compared to wild-type plants. Gene expression analysis revealed a significant shift in expression of hormone-associated genes in the transgenic plants. During water-stress (WS), P(SARK)::IPT plants displayed increased expression of brassinosteroid-related genes and repression of jasmonate-related genes. Changes in hormone homeostasis were associated with resource(s) mobilization during stress. The transgenic plants displayed differential expression of genes encoding enzymes associated with hormone synthesis and hormone-regulated pathways. These changes and associated hormonal crosstalk resulted in the modification of source/sink relationships and a stronger sink capacity of the P(SARK)::IPT plants during WS. As a result, the transgenic plants had higher GY with improved quality (nutrients and starch content).
MeSH terms
Alkyl and Aryl Transferases; Biomass; Chlorophyll; Cytokinins; Dehydration; Droughts; Edible Grain; Gene Expression Profiling; Gene Expression Regulation, Plant; Homeostasis; Oryza; Plant Growth Regulators; Plant Leaves; Plant Proteins; Plants, Genetically Modified; Promoter Regions, Genetic; Seedlings; Starch; Sucrose; Time Factors
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