Mutations in ABO1/ELO2, a subunit of holo-Elongator, increase abscisic acid sensitivity and drought tolerance in Arabidopsis thaliana.
The phytohormone abscisic acid (ABA) plays an important role in modulating plant growth, development, and stress responses. In a genetic screen for mutants with altered drought stress responses, we identified an ABA-overly sensitive mutant, the abo1 mutant, which showed a drought-resistant phenotype. The abo1 mutation enhances ABA-induced stomatal closing and increases ABA sensitivity in inhibiting seedling growth. abo1 mutants are more resistant to oxidative stress than the wild type and show reduced levels of transcripts of several stress- or ABA-responsive genes. Interestingly, the mutation also differentially modulates the development and growth of adjacent guard cells. Map-based cloning identified ABO1 as a new allele of ELO2, which encodes a homolog of Saccharomyces cerevisiae Iki3/Elp1/Tot1 and human IkappaB kinase-associated protein. Iki3/Elp1/Tot1 is the largest subunit of Elongator, a multifunctional complex with roles in transcription elongation, secretion, and tRNA modification. Ecotopic expression of plant ABO1/ELO2 in a tot1/elp1Delta yeast Elongator mutant complements resistance to zymocin, a yeast killer toxin complex, indicating that ABO1/ELO2 substitutes for the toxin-relevant function of yeast Elongator subunit Tot1/Elp1. Our results uncover crucial roles for ABO1/ELO2 in modulating ABA and drought responses in Arabidopsis thaliana.
Chen
Zhizhong
Z
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100094, People's Republic of China.
Zhang
Hairong
H
Jablonowski
Daniel
D
Zhou
Xiaofeng
X
Ren
Xiaozhi
X
Hong
Xuhui
X
Schaffrath
Raffael
R
Zhu
Jian-Kang
JK
Gong
Zhizhong
Z
D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000033:anatomy & histology / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004190:Disasters; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D005816:Genetic Complementation Test; D018525:Germination / Q000187:drug effects; D051548:Histone Acetyltransferases / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D018384:Oxidative Stress / Q000187:drug effects; D010445:Peptide Elongation Factors / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development; D012639:Seeds / Q000187:drug effects; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins; D010445:Peptide Elongation Factors; D021122:Protein Subunits; D012333:RNA, Messenger; D029701:Saccharomyces cerevisiae Proteins; D000040:Abscisic Acid; D051548:Histone Acetyltransferases; C479559:IKI3 protein, S cerevisiae