Auxin response factor 2 (ARF2) plays a major role in regulating auxin-mediated leaf longevity.
J Exp Bot
; 61(5): 1419-30, 2010 Mar.
Article
en En
| MEDLINE
| ID: mdl-20164142
ABSTRACT
Auxin regulates a variety of physiological and developmental processes in plants. Although auxin acts as a suppressor of leaf senescence, its exact role in this respect has not been clearly defined, aside from circumstantial evidence. It was found here that ARF2 functions in the auxin-mediated control of Arabidopsis leaf longevity, as discovered by screening EMS mutant pools for a delayed leaf senescence phenotype. Two allelic mutations, ore14-1 and 14-2, caused a highly significant delay in all senescence parameters examined, including chlorophyll content, the photochemical efficiency of photosystem II, membrane ion leakage, and the expression of senescence-associated genes. A delay of senescence symptoms was also observed under various senescence-accelerating conditions, where detached leaves were treated with darkness, phytohormones, or oxidative stress. These results indicate that the gene defined by these mutations might be a key regulatory genetic component controlling functional leaf senescence. Map-based cloning of ORE14 revealed that it encodes ARF2, a member of the auxin response factor (ARF) protein family, which modulates early auxin-induced gene expression in plants. The ore14/arf2 mutation also conferred an increased sensitivity to exogenous auxin in hypocotyl growth inhibition, thereby demonstrating that ARF2 is a repressor of auxin signalling. Therefore, the ore14/arf2 lesion appears to cause reduced repression of auxin signalling with increased auxin sensitivity, leading to delayed senescence. Altogether, our data suggest that ARF2 positively regulates leaf senescence in Arabidopsis.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Proteínas Represoras
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Senescencia Celular
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Arabidopsis
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Hojas de la Planta
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Proteínas de Arabidopsis
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Ácidos Indolacéticos
Idioma:
En
Revista:
J Exp Bot
Asunto de la revista:
BOTANICA
Año:
2010
Tipo del documento:
Article