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Early transcriptional responses to mercury: a role for ethylene in mercury‐induced stress
Author(s) -
MonteroPalmero M. Belén,
MartínBarranco Amanda,
Escobar Carolina,
Hernández Luis E.
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12486
Subject(s) - ethylene , transcriptome , biochemistry , oxidase test , metabolism , oxidative stress , biology , nadph oxidase , chemistry , secondary metabolism , microbiology and biotechnology , botany , gene expression , enzyme , gene , biosynthesis , catalysis
Summary Understanding the cellular mechanisms of plant tolerance to mercury ( H g) is important for developing phytoremediation strategies of H g‐contaminated soils. The early responses of alfalfa ( M edicago sativa ) seedlings to H g were studied using transcriptomics analysis. A M edicago truncatula microarray was hybridized with high‐quality root RNA from M . sativa treated with 3 μM H g for 3, 6 and 24 h. The transcriptional pattern data were complementary to the measurements of root growth inhibition, lipid peroxidation, hydrogen peroxide ( H 2 O 2 ) accumulation and NADPH ‐oxidase activity as stress indexes. Of 559 differentially expressed genes ( DEG s), 91% were up‐regulated. The majority of DEG s were shared between the 3 and 6 h (60%) time points, including the ‘stress’, ‘secondary metabolism’ and ‘hormone metabolism’ functional categories. Genes from ethylene metabolism and signalling were highly represented, suggesting that this phytohormone may be relevant for metal perception and homeostasis. Ethylene‐insensitive alfalfa seedlings preincubated with the ethylene signalling inhibitor 1‐methylcyclopronene and A rabidopsis thaliana ein2‐5 mutants confirmed that ethylene participates in the early perception of H g stress. It modulates root growth inhibition, NADPH ‐oxidase activity and H g‐induced apoplastic H 2 O 2 accumulation. Therefore, ethylene signalling attenuation could be useful in future phytotechnological applications to ameliorate stress symptoms in H g‐polluted plants.