Stability of small ubiquitin-like modifier (SUMO) proteases OVERLY TOLERANT TO SALT1 and -2 modulates salicylic acid signalling and SUMO1/2 conjugation in Arabidopsis thaliana.
Small ubiquitin-like modifier proteases 1 and 2 (SUMO1/2) have been linked to the regulation of salicylic acid (SA)-mediated defence signalling in Arabidopsis thaliana. In order to define the role of the SUMO proteases OVERLY TOLERANT TO SALT1 and -2 (OTS1/2) in defence and to provide insight into SUMO1/2-mediated regulation of SA signalling, we examined the status of SA-mediated defences in ots1/2 mutants. The ots1 ots2 double mutant displayed enhanced resistance to virulent Pseudomonas syringae and higher levels of SA compared with wild-type (WT) plants. Furthermore, ots1 ots2 mutants exhibited upregulated expression of the SA biosynthesis gene ICS1 in addition to enhanced SA-responsive ICS1 expression beyond that of WT. SA stimulated OTS1/2 degradation and promoted accumulation of SUMO1/2 conjugates. These results indicate that OTS1 and -2 act in a feedback loop in SA signalling and that de novo OTS1/2 synthesis works antagonistically to SA-promoted degradation, adjusting the abundance of OTS1/2 to moderate SA signalling. Accumulation of SUMO1/2 conjugates coincides with SA-promoted OTS degradation and may play a positive role in SA-mediated signalling in addition to its repressive roles reported elsewhere.
Biological & Biomedical Sciences, Durham University, Durham DH1 3LE, UK Present address: Plant proteolysis and signalling laboratory, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Mark
M
Bailey
Biological & Biomedical Sciences, Durham University, Durham DH1 3LE, UK.
Anjil
A
Srivastava
Biological & Biomedical Sciences, Durham University, Durham DH1 3LE, UK Department of BioSciences, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy.
Lucio
L
Conti
Biological & Biomedical Sciences, Durham University, Durham DH1 3LE, UK.
Stuart
S
Nelis
Biological & Biomedical Sciences, Durham University, Durham DH1 3LE, UK.
Cunjin
C
Zhang
Geoffrey Pope Building, Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
Hannah
H
Florance
Cell and Molecular Sciences, The James Hutton Institute, Dundee DD2 5DA, UK.
Andrew
A
Love
Plant Science Group, School of Life Sciences, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
Joel
J
Milner
School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7ES, UK.
Richard
R
Napier
Geoffrey Pope Building, Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
Murray
M
Grant
Biological & Biomedical Sciences, Durham University, Durham DH1 3LE, UK ari.sadanandom@durham.ac.uk.
Ari
A
Sadanandom
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D010935:Plant Diseases / Q000276:immunology; D057865:Plant Immunity; D044224:Pseudomonas syringae / Q000502:physiology*; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction
D029681:Arabidopsis Proteins; C477512:SUM1 protein, Arabidopsis; C477513:SUM2 protein, Arabidopsis; D003546:Cysteine Endopeptidases; C535127:OTS1 protein, Arabidopsis; C535128:OTS2 protein, Arabidopsis; D020156:Salicylic Acid
Arabidopsis thaliana; SUMO protease; SUMOylation.; defence; pathogen; salicylic acid (SA); small ubiquitin-like modifier (SUMO)