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

作者：Bailey Mark; Srivastava Anjil; Conti Lucio; Nelis Stuart; Zhang Cunjin; Florance Hannah; Love Andrew; Milner Joel; Napier Richard; Grant Murray; Sadanandom Ari^*

来源：Journal of Experimental Botany, 2016, 67(1): 353-363.

DOI：10.1093/jxb/erv468

• Arabidopsis thaliana
• defence
• pathogen
• salicylic acid (SA)
• small ubiquitin-like modifier (SUMO)
• SUMO protease
• SUMOylation

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.

• 出版日期2016-1