In:
The Plant Cell, Oxford University Press (OUP), Vol. 23, No. 6 ( 2011-06-01), p. 2169-2183
Abstract:
Cytokinins (CKs) regulate plant growth and development via a complex network of CK signaling. Here, we perform functional analyses with CK-deficient plants to provide direct evidence that CKs negatively regulate salt and drought stress signaling. All CK-deficient plants with reduced levels of various CKs exhibited a strong stress-tolerant phenotype that was associated with increased cell membrane integrity and abscisic acid (ABA) hypersensitivity rather than stomatal density and ABA-mediated stomatal closure. Expression of the Arabidopsis thaliana ISOPENTENYL-TRANSFERASE genes involved in the biosynthesis of bioactive CKs and the majority of the Arabidopsis CYTOKININ OXIDASES/DEHYDROGENASES genes was repressed by stress and ABA treatments, leading to a decrease in biologically active CK contents. These results demonstrate a novel mechanism for survival under abiotic stress conditions via the homeostatic regulation of steady state CK levels. Additionally, under normal conditions, although CK deficiency increased the sensitivity of plants to exogenous ABA, it caused a downregulation of key ABA biosynthetic genes, leading to a significant reduction in endogenous ABA levels in CK-deficient plants relative to the wild type. Taken together, this study provides direct evidence that mutual regulation mechanisms exist between the CK and ABA metabolism and signals underlying different processes regulating plant adaptation to stressors as well as plant growth and development.
Type of Medium:
Online Resource
ISSN:
1532-298X
,
1040-4651
DOI:
10.1105/tpc.111.087395
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2011
detail.hit.zdb_id:
623171-8
detail.hit.zdb_id:
2004373-9
SSG:
12
Permalink