|Guo, Peiguo - OKLAHOMA STATE UNIV.|
|Carver, Brett F. - OKLAHOMA STATE UNIV.|
|Li, Ronghua - OKLAHOMA STATE UNIV.|
|Bernardo, Amy - OKLAHOMA STATE UNIV.|
|Baum, Michael - ICARDA SYRIA|
Submitted to: Molecular Genetics and Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 7, 2006
Publication Date: October 10, 2006
Citation: Guo, P., Bai, G., Carver, B., Li, R., Bernardo, A., Baum, M. 2006. Transcriptional analysis between two wheat near-isogenic lines contrasting in aluminum (al) tolerance under al stress. Molecular Genetics and Genomics. 277:1-12. Interpretive Summary: Aluminum toxicity is a common problem in wheat grown on soils with low pH. To understand the mechanisms of aluminum (Al) tolerance and identify genes responsible for Al tolerance in wheat, gene expression levels were compared in Al-stressed roots of wheat lines Chisholm-T (Al-tolerant) and Chisholm-S (Al-sensitive). These two lines have a similar genetic background and differ mainly in aluminum tolerance. Fifty-seven genes were found to be highly expressed in only one line, but not the other. Twenty-eight genes including genes for aluminum-activated malate transporter-1, ent-kaurenoic acid oxidase-1, B-glucosidase, lectin, histidine kinase, and phospoenolpyruvate carboxylase were expressed more abundantly in Chisholm-T. The results suggest that Al tolerance may be mediated by several genes with different functions. This information may be useful for increasing Al tolerance and protecting root growth under Al stress.
Technical Abstract: To understand the mechanisms of aluminum (Al) tolerance and identify genes responsible for Al tolerance in wheat (Triticum aestivum L.), suppression subtractive hybridization (SSH) libraries were constructed from Al-stressed roots for two wheat near- isogenic lines (NILs), Chisholm-T (Al-tolerant) and Chisholm-S (Al-sensitive). A total of 1628 cDNA clones representing 1065 putative genes from the libraries were spotted on glass slides. Relative expression levels of those genes were compared between Chisholm-T and Chisholm-S at seven time points of Al stress: 15 min, 1 h, 3 h, 6 h, 1 d, 3 d and 7 d. Fifty-seven genes were differentially expressed for at least one time point of Al treatment. Among them, 28 genes including genes for aluminum-activated malate transporter-1, ent-kaurenoic acid oxidase-1, B-glucosidase, lectin, histidine kinase, and phospoenolpyruvate carboxylase showed more abundant transcripts in Chisholm-T and therefore may facilitate Al tolerance. In addition, a set of genes related to senescence and starvation of nitrogen, iron and sulfur, such as copper chaperone homolog, nitrogen regulatory gene-2, yellow stripe-1, and methylthioribose kinase, was highly expressed in Chisholm-S under Al stress. The results suggest that Al tolerance may be co-regulated by multiple genes with diverse functions, and those genes abundantly expressed in Chisholm-T may play important roles in enhancing Al tolerance and protecting root growth under Al stress. The highly expressed genes in Chisholm-S under Al stress may be symptomatic of root growth repression and restricted uptake of essential nutrient elements, leading to root senescence.