title: NORE1/SAUL1 integrates temperature-dependent defense programs involving SGT1b and PAD4 pathways and leaf senescence in Arabidopsis.
abstract: Leaf senescence is not only primarily governed by developmental age but also influenced by various internal and external factors. Although some genes that control leaf senescence have been identified, the detailed regulatory mechanisms underlying integration of diverse senescence-associated signals into the senescence programs remain to be elucidated. To dissect the regulatory pathways involved in leaf senescence, we isolated the not oresara1-1 (nore1-1) mutant showing accelerated leaf senescence phenotypes from an EMS-mutagenized Arabidopsis thaliana population. We found that altered transcriptional programs in defense response-related processes were associated with the accelerated leaf senescence phenotypes observed in nore1-1 through microarray analysis. The nore1-1 mutation activated defense program, leading to enhanced disease resistance. Intriguingly, high ambient temperature effectively suppresses the early senescence and death phenotypes of nore1-1. The gene responsible for the phenotypes of nore1-1 contains a missense mutation in SENESCENCE-ASSOCIATED E3 UBIQUITIN LIGASE 1 (SAUL1), which was reported as a negative regulator of premature senescence in the light intensity- and PHYTOALEXIN DEFICIENT 4 (PAD4)-dependent manner. Through extensive double mutant analyses, we recently identified suppressor of the G2 Allele of SKP1b (SGT1b), one of the positive regulators for disease resistance conferred by many resistance (R) proteins, as a downstream signaling component in NORE1-mediated senescence and cell death pathways. In conclusion, NORE1/SAUL1 is a key factor integrating signals from temperature-dependent defense programs and leaf senescence in Arabidopsis. These findings provide a new insight that plants might utilize defense response program in regulating leaf senescence process, possibly through recruiting the related genes during the evolution of the leaf senescence program.
authors.affiliation: Department of Life Sciences, POSTECH, Pohang, 37673, Republic of Korea.
authors.forename: Il Hwan
authors.initials: IH
authors.lastname: Lee
authors.affiliation: Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea.
authors.forename: In Chul
authors.initials: IC
authors.lastname: Lee
authors.affiliation: Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea.
authors.forename: Jeongsik
authors.initials: J
authors.lastname: Kim
authors.affiliation: Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea.
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA.
authors.forename: Eui-Hwan
authors.initials: EH
authors.lastname: Chung
authors.affiliation: Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea.
authors.forename: Hyo Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang, 37673, Republic of Korea.
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Department of Bioscience, Chungnam National University, Daejeon, 34134, Republic of Korea.
authors.forename: Yong Min
authors.initials: YM
authors.lastname: Kim
authors.affiliation: Department of Bioscience, Chungnam National University, Daejeon, 34134, Republic of Korea.
authors.forename: Sin Kyu
authors.initials: SK
authors.lastname: Kang
authors.affiliation: Center for Plant Aging Research, Institute for Basic Science (IBS), Daegu, 42988, Republic of Korea. nam@dgist.ac.kr.|Department of New Biology, DGIST, Daegu, 42988, Republic of Korea. nam@dgist.ac.kr.
authors.forename: Hong Gil
authors.initials: HG
authors.lastname: Nam
authors.affiliation: Department of New Biology, DGIST, Daegu, 42988, Republic of Korea. hrwoo@dgist.ac.kr.
authors.forename: Hye Ryun
authors.initials: HR
authors.lastname: Woo
authors.affiliation: Department of New Biology, DGIST, Daegu, 42988, Republic of Korea. polim@dgist.ac.kr.
authors.forename: Pyung Ok
authors.initials: PO
authors.lastname: Lim
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000276:immunology / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D016923:Cell Death; D002874:Chromosome Mapping; D060467:Disease Resistance; D008027:Light; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000502:physiology / Q000528:radiation effects; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction; D013696:Temperature; D013997:Time Factors; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; C452192:SGT1b protein, Arabidopsis; C576658:SAUL1 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; D002265:Carboxylic Ester Hydrolases; C400766:PAD4 protein, Arabidopsis; D020156:Salicylic Acid