UBC 18 mediates ERF 1 degradation under light–dark cycles

Summary Ethylene Response Factor 1 ( ERF 1 ) plays a crucial role in biotic and abiotic stress responses. Previous studies have shown that ERF 1 regulates stress‐responsive gene expression by binding to different cis ‐acting elements in response to various stress signals. ERF 1 was also reported to...

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Bibliographic Details
Published inThe New phytologist Vol. 213; no. 3; pp. 1156 - 1167
Main Authors Cheng, Mei‐Chun, Kuo, Wen‐Chieh, Wang, Yi‐Ming, Chen, Hsing‐Yu, Lin, Tsan‐Piao
Format Journal Article
LanguageEnglish
Published 01.02.2017
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Summary:Summary Ethylene Response Factor 1 ( ERF 1 ) plays a crucial role in biotic and abiotic stress responses. Previous studies have shown that ERF 1 regulates stress‐responsive gene expression by binding to different cis ‐acting elements in response to various stress signals. ERF 1 was also reported to be unstable in the dark, and it regulates hypocotyl elongation. Here, we elucidated the mechanism underlying degradation of ERF 1. Yeast two‐hybrid screening showed that UBIQUITIN ‐ CONJUGATING ENZYME 18 ( UBC 18) interacted with ERF 1. The interaction between ERF 1 and UBC 18 was verified using pull‐down assays and coimmunoprecipitation analyses. We then compared the ERF 1 protein abundance in the UBC 18 mutant and overexpression plants. Based on the results of protein degradation and in vivo ubiquitination assays, we proposed that UBC 18 mediates ERF 1 ubiquitination and degradation. ERF 1 was more stable in UBC 18 mutants and less stable in UBC 18 overexpression lines compared with that in wild‐type plants. ERF 1 was degraded by the 26S proteasome system via regulation of UBC 18 and promotes dark‐repression of downstream genes and proline accumulation. UBC 18 negatively regulated drought and salt stress responses by altering the abundance of ERF 1 and the expression of genes downstream of ERF 1.
ISSN:0028-646X
1469-8137
DOI:10.1111/nph.14272