Auxin response factor 2 (ARF2) plays a major role in regulating auxin-mediated leaf longevity
Open Access
- 17 February 2010
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Experimental Botany
- Vol. 61 (5), 1419-1430
- https://doi.org/10.1093/jxb/erq010
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.Keywords
This publication has 47 references indexed in Scilit:
- An Arabidopsis Mitogen-Activated Protein Kinase Cascade, MKK9-MPK6, Plays a Role in Leaf SenescencePlant Physiology, 2009
- Integration of auxin and brassinosteroid pathways by Auxin Response Factor 2Proceedings of the National Academy of Sciences of the United States of America, 2008
- FIONA1 Is Essential for Regulating Period Length in theArabidopsisCircadian ClockPlant Cell, 2008
- Leaf SenescenceAnnual Review of Plant Biology, 2007
- Transcription Analysis of Arabidopsis Membrane Transporters and Hormone Pathways during Developmental and Induced Leaf SenescencePlant Physiology, 2006
- Aux/IAA Proteins Contain a Potent Transcriptional Repression DomainPlant Cell, 2004
- The Roles of Auxin Response Factor Domains in Auxin-Responsive TranscriptionPlant Cell, 2003
- TheBLADE-ON-PETIOLE 1gene controls leaf pattern formation through the modulation of meristematic activity inArabidopsisDevelopment, 2003
- Last exit: senescence, abscission, and meristem arrest in Arabidopsis.Plant Cell, 1997
- AUXIN IN RELATION TO LEAF BLADE ABSCISSIONPlant Physiology, 1951