Analysis of Cytokinin Mutants and Regulation of Cytokinin Metabolic Genes Reveals Important Regulatory Roles of Cytokinins in Drought, Salt and Abscisic Acid Responses, and Abscisic Acid Biosynthesis

0365273 - ÚEB 2012 RIV US eng J - Journal Article
Nishiyama, R. - Watanabe, Y. - Werner, T. - Vaňková, Radomíra - Schmülling, T. - Tran, L. S. P. … Total 13 authors
Analysis of Cytokinin Mutants and Regulation of Cytokinin Metabolic Genes Reveals Important Regulatory Roles of Cytokinins in Drought, Salt and Abscisic Acid Responses, and Abscisic Acid Biosynthesis.
Plant Cell. Roč. 23, č. 6 (2011), s. 2169-2183. ISSN 1040-4651. E-ISSN 1532-298X
Institutional research plan: CEZ:AV0Z50380511
Keywords : TRANSGENIC TOBACCO PLANTS * WATER-STRESS * LEAF SENESCENCE
Subject RIV: ED - Physiology
Impact factor: 8.987, year: 2011

Functional analyses of CK-deficient AtCKX overexpressers or atipt mutant provided direct evidence that CKs negatively regulate salt and drought stress signalings. All of the AtCKX overexpressers and the atipt1 3 5 7 mutant with reduced levels of various CKs exhibited a strong stress tolerant phenotype that was associated with increased cell membrane integrity and stability rather than stomatal density and ABA-mediated stomatal closure. Expression of all AtIPT genes and the majority of the AtCKX genes was repressed by stress and ABA treatments. Additionally, while CK deficiency increased sensitivity to exogenous ABA, it caused down-regulation of key ABA biosynthetic genes, leading to a significant reduction in endogenous ABA levels in CK-deficient plants relative to wild-type. These data demonstrate the importance of the ABA/CK ratio and a vital CK-dependent homeostatic control of ABA metabolism, ABA sensing and response.
Permanent Link: http://hdl.handle.net/11104/0200556