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Plant Physiol. 2017 Dec;175(4):1878-1892. doi: 10.1104/pp.17.01319. Epub 2017 Oct 31.

The E3 Ligase TaSAP5 Alters Drought Stress Responses by Promoting the Degradation of DRIP Proteins.

Author information

1
State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, People's Republic of China.
2
State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing 100193, People's Republic of China qxsun@cau.edu.cn yingyin@cau.edu.cn.

Abstract

In Arabidopsis (Arabidopsis thaliana) plants growing under normal conditions, DEHYDRATION-RESPONSIVE ELEMENT BINDING PROTEIN2A (DREB2A) is present at low levels because it is ubiquitinated and destabilized by DREB2A INTERACTING PROTEIN1 (DRIP1) and DRIP2 through 26S proteasome-mediated proteolysis. Drought stress counteracts the ubiquitination and proteolysis of DREB2A, thus allowing the accumulation of sufficient amounts of DREB2A protein to activate downstream gene expression. The mechanisms leading to drought stress-mediated DREB2A accumulation are still unclear. Here, we report that the wheat (Triticum aestivum) TaSAP5 protein, which contains an A20/AN1 domain, acts as an E3 ubiquitin ligase to mediate DRIP degradation and thus increase DREB2A protein levels. Drought induces TaSAP5 expression in wheat, and TaSAP5 overexpression in Arabidopsis and wheat seedlings increased their drought tolerance, as measured by survival rate and grain yield under severe drought stress. TaSAP5 can interact with and ubiquitinate TaDRIP, as well as AtDRIP1 and AtDRIP2, leading to their subsequent degradation through the 26S proteasome pathway. Consistent with this, TaSAP5 overexpression enhances DRIP degradation and increases the levels of DREB2A protein and its downstream targets. These results suggest that TaSAP5 acts to link drought with DREB2A accumulation and illustrate the molecular mechanisms involved in this process.

PMID:
29089392
PMCID:
PMC5717742
DOI:
10.1104/pp.17.01319
[Indexed for MEDLINE]
Free PMC Article

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