Open AccessCytokinin‐mediated source/sink modifications improve drought tolerance and increase grain yield in rice under water‐stress
Author(s) -
Peleg Zvi,
Reguera Maria,
Tumimbang Ellen,
Walia Harkamal,
Blumwald Eduardo
Publication year - 2011
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/j.1467-7652.2010.00584.x
Subject(s) - biology , genetically modified rice , oryza sativa , brassinosteroid , cytokinin , genetically modified crops , transgene , drought tolerance , abiotic stress , gene , botany , agronomy , microbiology and biotechnology , arabidopsis , auxin , genetics , mutant
Summary 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).