Cytokinin-mediated source/sink modifications improve drought tolerance and increase grain yield in rice under water-stress

Zvi Peleg, Maria Reguera, Ellen Tumimbang, Harkamal Walia, Eduardo Blumwald

Research output: Contribution to journalArticlepeer-review

276 Scopus citations

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).

Original languageEnglish (US)
Pages (from-to)747-758
Number of pages12
JournalPlant Biotechnology Journal
Volume9
Issue number7
DOIs
StatePublished - Sep 2011

Keywords

  • Brassinosteroids
  • Cytokinin
  • Drought tolerance
  • Isopentenyltransferase
  • Source/sink balance
  • Starch
  • Sugar metabolism
  • water-deficit

ASJC Scopus subject areas

  • Biotechnology
  • Agronomy and Crop Science
  • Plant Science

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