title: Organ-specific proteomic analysis of drought-stressed soybean seedlings.
abstract: Changes in protein levels in drought-stressed soybean seedlings were analyzed using a proteomics approach. Three-day-old soybean seedlings were subjected to drought stress or treated with 10% polyethylene glycol (PEG) as osmotic stress. After treatment, the proteins were extracted from the leaf, hypocotyl, and root and separated using two-dimensional polyacrylamide gel electrophoresis. The root was the most drought-responsive organ, with the levels of 32, 13, and 12 proteins changing in response to drought stress, PEG treatment, and both, respectively. In the leaves of PEG-treated and drought-stressed seedlings, metabolism-related proteins increased and energy production- and protein synthesis-related proteins decreased. For 3 proteins present in all organs in drought-stressed plants, mRNA was differentially regulated: heat shock protein 70 and actin isoform B were upregulated, and methionine synthase was downregulated. mRNA expression patterns reflected those of protein levels, suggesting transcriptional regulation of these proteins. Western blot analysis confirmed the increase in ascorbate peroxidase in drought-stressed plants. The downregulation of mRNA and decreased protein levels of methionine synthase in the leaves, hypocotyl, and roots of drought-stressed plants, but not in other treatments, indicated that methionine synthase is a drought response protein. These results also suggest that the decreased methionine synthase in response to drought stress can impair the soybean seedling growth.
authors.affiliation: National Institute of Crop Science, Tsukuba 305-8518, Japan.
authors.forename: Payam Pour
authors.initials: PP
authors.lastname: Mohammadi
authors.forename: Ahmad
authors.initials: A
authors.lastname: Moieni
authors.forename: Susumu
authors.initials: S
authors.lastname: Hiraga
authors.forename: Setsuko
authors.initials: S
authors.lastname: Komatsu
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000235:genetics / Q000378:metabolism; D000199:Actins / Q000235:genetics / Q000378:metabolism; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D018546:Hypocotyl / Q000254:growth & development / Q000378:metabolism; D009997:Osmotic Pressure / Q000502:physiology; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D011092:Polyethylene Glycols / Q000494:pharmacology; D040901:Proteomics; D012333:RNA, Messenger / Q000378:metabolism; D036226:Seedlings / Q000378:metabolism; D013025:Glycine max / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; D018840:HSP70 Heat-Shock Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D011092:Polyethylene Glycols; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase