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Sulfate availability affects ABA levels and germination response to ABA and salt stress in A rabidopsis thaliana
Author(s) -
Cao MinJie,
Wang Zhen,
Zhao Qing,
Mao JieLi,
Speiser Anna,
Wirtz Markus,
Hell Rüdiger,
Zhu JianKang,
Xiang ChengBin
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12407
Subject(s) - abscisic acid , biochemistry , sulfur metabolism , cysteine , arabidopsis , nitrate reductase , biosynthesis , chemistry , arabidopsis thaliana , mutant , metabolism , ectopic expression , abiotic stress , wild type , jasmonic acid , microbiology and biotechnology , enzyme , biology , salicylic acid , gene
Summary Sulfur‐containing compounds play a critical role in the response of plants to abiotic stress factors including drought. The phytohormone abscisic acid ( ABA ) is the key regulator of responses to drought and high‐salt stress. However, our knowledge about interaction of S‐metabolism and ABA biosynthesis is scarce. Here we report that sulfate supply affects synthesis and steady‐state levels of ABA in Arabidopsis wild‐type seedlings. By using different mutants of the sulfate uptake and reduction pathway, we confirmed the impact of sulfate supply on steady‐state ABA content in Arabidopsis and demonstrated that this impact was due to cysteine availability. Loss of the chloroplast sulfate transporter3;1 function ( sultr3;1 ) resulted in significantly decreased aldehyde oxidase ( AO ) activity and ABA levels in seedlings and seeds. These mutant phenotypes could be reverted by exogenous application of cysteine or ectopic expression of SULTR 3;1. In addition the sultr3;1 mutant showed a decrease of xanthine dehydrogenase activity, but not of nitrate reductase, strongly indicating that in seedlings cysteine availability limits activity of the molybdenum co‐factor sulfurase, ABA 3, which requires cysteine as the S‐donor for sulfuration. Transcription of ABA 3 and NCED 3, encoding another key enzyme of the ABA biosynthesis pathway, was regulated by S‐supply in wild‐type seedlings. In contrast, ABA up‐regulated the transcript level of SULTR 3;1 and other S‐metabolism‐related genes. Our results provide evidence for a significant co‐regulation of S‐metabolism and ABA biosynthesis that operates to ensure sufficient cysteine for AO maturation and highlights the importance of sulfur for stress tolerance of plants.