Mechanisms of magnesium amelioration of aluminum toxicity in soybean at the gene expression level.
Micromolar concentration of magnesium (Mg) in culture solution is known to ameliorate aluminum (Al) toxicity in soybean and other leguminous species. To advance the understanding of this phenomenon at the level of gene expression in soybean, we undertook a comparative transcriptome analysis using DNA microarrays and Al-tolerant and Al-sensitive genotypes treated with Al ions alone or Al plus Mg ions. We observed a more rapid alteration of transcription for Al-tolerant than Al-sensitive soybean after introduction of Mg into Al-containing medium, but at 72 h, far more genes were altered (both upregulated and downregulated) in the Al-sensitive line, reflecting the known greater saving effect of Mg for Al-sensitive than Al-tolerant lines. Mg appears to ameliorate Al toxicity in the sensitive genotype by the dual mechanisms of (i) specifically increasing the expression level of several genes that are upregulated in the Al-treated, Al-tolerant genotype in the absence of Mg and (ii) possibly saving energy by decreasing expression of most genes relative to expression under Al stress. Mg-mediated reduction in gene expression also appears to be an important mechanism of Mg protection of the Al-tolerant genotype.
Department of Natural Resources and Environmental Sciences, Alabama A&M University, Normal, AL 35762, USA.
Dechassa
D
Duressa
Khairy M
KM
Soliman
Dongquan
D
Chen
D000535:Aluminum / Q000633:toxicity*; D016000:Cluster Analysis; D004351:Drug Resistance / Q000187:drug effects / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000502:physiology; D008274:Magnesium / Q000494:pharmacology*; D046228:Microarray Analysis; D010935:Plant Diseases / Q000139:chemically induced / Q000235:genetics / Q000517:prevention & control; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013025:Glycine max / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors; D054928:Validation Studies as Topic
D000535:Aluminum; D008274:Magnesium