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Thylakoid membrane oxidoreductase LTO1 / At VKOR is involved in ABA‐mediated response to osmotic stress in Arabidopsis
Author(s) -
Lu Ying,
Peng JunJie,
Yu ZhiBo,
Du JiaJia,
Xu JiaNing,
Wang XiaoYun
Publication year - 2015
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/ppl.12268
Subject(s) - abscisic acid , mutant , osmotic shock , arabidopsis , complementation , biochemistry , microbiology and biotechnology , wild type , biology , thylakoid , chemistry , gene , chloroplast
Arabidopsis lumen thiol oxidoreductase 1 ( LTO1 ) – the At 4g35760 gene product – was previously found to be related to reactive oxygen species ( ROS ) accumulation. Here, we show that ROS accumulated in a mutant Arabidopsis line ( lto1‐2 , mutant of LTO1/AtVKOR ) under osmotic stress at a higher level than that observed in wild‐type and transgenic complemented plants of the lto1‐2 mutant (lto1‐ 2C , transgenic complemented plants of lto1‐2 ). Because ROS accumulation in osmotic stress is triggered by abscisic acid ( ABA ), an ABA ‐responsive gene, Annexin 1 ( AnnAt1 ), was selected to study the response. Osmotic stress or exogenous ABA can significantly upregulate the transcription of AnnAt1 in wild‐type and lto1‐ 2C plants. Only a slight change in the transcriptional abundance of AnnAt1 was observed under osmotic stress in the lto1‐2 mutant, but exogenous ABA application could increase the expression of AnnAt1 , which suggested that exogenous ABA had a partial complementation role. Because the transcription of AnnAt1 is regulated by ABRE (ABA‐responsive elements) binding proteins ( AREBs )/ABRE binding factors ( ABFs ), the expression of AREBs / ABFs was also analyzed. The transcription of AREBs / ABFs in the lto1‐2 mutant was not induced by osmotic stress but was significantly upregulated by exogenous ABA , which significantly differs from the wild‐type and lto1‐ 2C plant responses. Similarly, the expression of another ABA ‐responsive gene, RD29B (responsive to desiccation stress gene 29B), in the lto1‐2 mutant was also upregulated by exogenous ABA . The partial complementation of mutants by ABA indicated that the ABA signal transduction pathway was not significantly affected in the lto1‐2 mutant. Taken together, these results suggest that LTO1 is involved in ABA ‐mediated response to osmotic stress, possibly by affecting the biosynthesis of endogenous ABA .