Research Article
Senescence-Inducible Expression of Isopentenyl Transferase Extends Leaf Life, Increases Drought Stress Resistance and Alters Cytokinin Metabolism in Cassava
Article first published online: 12 MAY 2010
DOI: 10.1111/j.1744-7909.2010.00956.x
© 2010 Institute of Botany, Chinese Academy of Sciences
Additional Information
How to Cite
Zhang, P., Wang, W.-Q., Zhang, G.-L., Kaminek, M., Dobrev, P., Xu, J. and Gruissem, W. (2010), Senescence-Inducible Expression of Isopentenyl Transferase Extends Leaf Life, Increases Drought Stress Resistance and Alters Cytokinin Metabolism in Cassava. Journal of Integrative Plant Biology, 52: 653–669. doi: 10.1111/j.1744-7909.2010.00956.x
Publication History
- Issue published online: 24 JUN 2010
- Article first published online: 12 MAY 2010
- Received 24 Sept. 2009 Accepted 21 Mar. 2010
Abstract
Cassava (Manihot esculenta Crantz) sheds its leaves during growth, especially within the tropical dry season. With the production of SAG12-IPT transgenic cassava we want to test the level of leaf retention and altered cytokinin metabolism of transgenic plants via the autoregulatory senescence inhibition system. After confirmation of transgene expression by molecular analysis and phenotype examination in greenhouse plants, two transgenic plant lines, 529-28 and 529-48, were chosen for further investigation. Detached mature leaves of 529-28 plants retained high levels of chlorophyll compared with wild-type leaves after dark-induced senescence treatment. Line 529-28 showed significant drought tolerance as indicated by stay-green capacity after drought stress treatment. Field experiments proved that leaf senescence syndrome was significantly delayed in 529-28 plants in comparison with wild-type and 529-48 plants. Physiological and agronomical characterizations of these plants also revealed that the induced expression of IPT had effects on photosynthesis, sugar allocation and nitrogen partitioning. Importantly, the 529-28 plants accumulated a high level of trans-zeatin-type cytokinins particularly of corresponding storage O-glucosides to maintain cytokinin homeostasis. Our study proves the feasibility of prolonging the leaf life of woody cassava and also sheds light on the control of cytokinin homeostasis in cassava leaves.

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