SIZ1 Small Ubiquitin-Like Modifier E3 Ligase Facilitates Basal Thermotolerance in Arabidopsis Independent of Salicylic Acid

• Published in: Plant physiology (Bethesda) 2006-12, Vol.142 (4), p.1548-1558
• Main Authors: Yoo, Chan Yul, Miura, Kenji, Jin, Jing Bo, Lee, Jiyoung, Park, Hyeong Cheol, Salt, David E, Yun, Dae-Jin, Bressan, Ray A, Hasegawa, Paul M
• Format: Article
• Language: English
• Subjects: Arabidopsis - drug effects; Arabidopsis - metabolism; Arabidopsis - physiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis Proteins - physiology; Arabidopsis thaliana; Biological and medical sciences; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Environmental Stress and Adaptation to Stress; Fundamental and applied biological sciences. Psychology; Gene expression regulation; Gene Expression Regulation, Plant; Genes; Genes. Genome; Heat; Heat Shock Transcription Factors; Heat tolerance; Heat-Shock Proteins - metabolism; High temperature; Ligases - genetics; Ligases - metabolism; Ligases - physiology; Metazoa; Molecular and cellular biology; Molecular genetics; Mutation; Plants; Regulon - physiology; Salicylic Acid - metabolism; Seedlings; Shock heating; Small Ubiquitin-Related Modifier Proteins - genetics; Small Ubiquitin-Related Modifier Proteins - metabolism; Small Ubiquitin-Related Modifier Proteins - physiology; Temperature; Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Transcriptional regulatory elements; Ubiquitin-Protein Ligases - genetics; Ubiquitin-Protein Ligases - metabolism; Ubiquitin-Protein Ligases - physiology
• ISSN: 0032-0889; 1532-2548; 1532-2548
• DOI: 10.1104/pp.106.088831

Small ubiquitin-like modifier (SUMO) conjugation/deconjugation to heat shock transcription factors regulates DNA binding of the peptides and activation of heat shock protein gene expression that modulates thermal adaptation in metazoans. SIZ1 is a SUMO E3 ligase that facilitates SUMO conjugation to substrate target proteins (sumoylation) in Arabidopsis (Arabidopsis thaliana). siz1 T-DNA insertional mutations (siz1-2 and siz1-3; Miura et al., 2005) cause basal, but not acquired, thermosensitivity that occurs in conjunction with hyperaccumulation of salicylic acid (SA). NahG encodes a salicylate hydroxylase, and expression in siz1-2 seedlings reduces endogenous SA accumulation to that of wild-type levels and further increases thermosensitivity. High temperature induces SUMO1/2 conjugation to peptides in wild type but to a substantially lesser degree in siz1 mutants. However, heat shock-induced expression of genes, including heat shock proteins, ascorbate peroxidase 1 and 2, is similar in siz1 and wild-type seedlings. Together, these results indicate that SIZ1 and, by inference, sumoylation facilitate basal thermotolerance through processes that are SA independent.